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Journal of Materials Sciences & Technology
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2001, Vol.17 No.01
Online: 2001-01-28
Research Articles
 
Research Articles
1 T.A. Popovich, O.V. Arestov, A.A.Popovich, A.S. Kuchma
MÖssbauer Study of Mechanical Alloying Fe-Ti and Fe-Ti-N Alloys
Mossbauer spectrometry was used to study the peculiarity of formation of nonequilibrium phase in Fe-Ti and Fe-Ti-N systems by mechanical alloying. Mossbauer spectra of powders show the formation of nonequilibrium crystalline phase and intermetallic compounds during a mechanical alloying process depending on the alloy composition and the milling time.
2001 Vol. 17 (01): 1-2 [Abstract] ( 355 ) [HTML 1KB] [PDF 637KB] ( 365 )
3 Junbao ZHANG, Tingquan LEI, Guangwu WEN, Yu ZHOU
Synthesis and Ceramic Conversion of Polysiloxazane to Silicon Oxynitride
Amorphous silicon oxynitride powders have been obtained by pyrolysis of polysiloxazane in a stream of anhydrous NH3 at the temperature up to 1000℃. The polysiloxazane is fabricated from ammonolysis of chloropolysiloxane that is produced by the hydrolysis of silicon tetrachloride. The conversion of polysiloxazane to silicon oxynitride and the structural features of the final powders have also been studied by infrared spectra, elemental composition and X-ray diffraction analysis and SEM observation.
2001 Vol. 17 (01): 3-4 [Abstract] ( 413 ) [HTML 1KB] [PDF 112KB] ( 415 )
5 K.H.Wu, JL.Ma
Effects of Ta Addition on Microstructure and Transformation Behavior of Ni-Ti Alloys
The effect of adding Ta on the changes of microstructure and M-s temperature of a dual-phase shape memory alloy with compositions of (Ni51Ti49)(1-x)Ta-x and Ni50Ti50-yTay, were systematically studied. An optical microscope, SEM, X-ray diffraction and DSC were utilized in this work. The evolution of the microstructure as a function of Ta content was characterized. The variation of the Ni/Ti ratio in the NiTi phase plays an important role in the change of the M-s temperatures due to the addition of Ta. A pseudobinary NiTi-Ta phase diagram was proposed based on these results.
2001 Vol. 17 (01): 5-6 [Abstract] ( 365 ) [HTML 1KB] [PDF 231KB] ( 395 )
7 Dianran YAN, Jining HE, XiangZhi LI, Yangai LIU, Yu ZHOU, Dechang JIA
Corrosion Resistance of Plasma Sprayed Ceramic Composite Coatings on Q235 Substrate
The corrosion resistance of SiO2/A12O3, TiO2/Al2O3 and (SiO2+TiO2)/Al2O3 ceramic composite coatings on Q235 substrate fabricated by means of plasma spraying was investigated. The results show that A12O3+13 wt pct TiO2 ceramic coating has the highest density, the lowest connected porosity and the best corrosion resistance. The corrosion mechanism of Q235 with ceramic coating has also been studied.
2001 Vol. 17 (01): 7-8 [Abstract] ( 413 ) [HTML 1KB] [PDF 182KB] ( 384 )
9 Jingpei XIE, Yaomin ZHU, Yanpei SONG, Xiaoying WANG, Qu, e CHEN
Damping Property of Supersaturated ZnA127Ce Alloy during Natural Aging
The microstructures and damping property of supersaturated ZnA127Ce alloy during natural aging have been investigated. H-800 TEM was mainly used to research the microstructures. The relationship between microstructure and damping property was primarily studied. The results showed that solution plus natural aging was the best heat treatment, which could improve the damping property. Both continuous precipitation and cellular reaction occurred during the aging. Continuous precipitation follows the sequence: β→spherical GP zones→elliptical GP zones→intermediate phase R→η. The cellular reaction can be written as follows: β→α+η+ε.
2001 Vol. 17 (01): 9-10 [Abstract] ( 357 ) [HTML 1KB] [PDF 138KB] ( 330 )
11 Xuexi ZHANG, Dezun WANG, Dongyan DING, Congkai YAO
Numerical Simulation of Unidirectional Infiltration of Silicon Carbide Preforms
Mathematical model of unidirectional infiltration was set up and metal infiltration velocity and temperature fields of the metal, preform, and composites were calculated using the finite difference method. The metal infiltration velocity has a close relationship with infiltration time. It is very large after the infiltration begins in a few seconds, then the velocity keeps almost constant. The temperature field of the composite proves that metal matrix composites (MMCs) after unidirectional pressure infiltration can solidify from the entrance of the preform to the infiltration front, which is useful for obtaining the MMCs with low porosity and high properties.
2001 Vol. 17 (01): 11-12 [Abstract] ( 396 ) [HTML 1KB] [PDF 106KB] ( 350 )
13 Liming WANG, Xianglong MENG, Wei CAI, Liancheng ZHAO
Two-way Shape Memory Effect in a Ti-Ni-Nb Shape Memory Alloy with Wide Hysteresis
A two-way shape memory effect (TWSM E) in the Ti46.3Ni44.7Nb9 alloy has been systematically investigated by means of bending test and transmission electron microscopy (TEM) observations. Based on the analysis of the microstructure after training, the mechanism of TWSME in the Ti46.3 Ni44.7Nb9 alloy has been discussed.
2001 Vol. 17 (01): 13-14 [Abstract] ( 362 ) [HTML 1KB] [PDF 162KB] ( 365 )
15 Mingwei LI, Jingchuan ZHU, Zhongda YIN, Xiaoqiang LI, Zuyan LIU, Jae-Ho Jeon
Synthesis of MoSi2 by Mechanical Alloying
The microstructure evolution of mechanical alloyed Mo-66.7%Si powder using the high-energy ball mill has been studied by X-ray diffraction and scanning electron microscopy. The results showed that MoSi2 can be synthesized by MA of Mo-66.7%Si powder mixtures. Cold welding behavior between Mo and Si powders plays an important role in the preparation of MoSi2 by the MA.
2001 Vol. 17 (01): 15-16 [Abstract] ( 390 ) [HTML 1KB] [PDF 210KB] ( 362 )
17 Baoyan ZHANG, Xiaogbao CHEN. Ping LI, Xiaosu YI
Toughness and Hot/Wet Properties of a Novel Modified BMI/Carbon Fiber Composite
The toughness and hot/wet properties of a novel modified bismaleimide (BMI) 5428/carbon fiber composite was investigated. Results indicate that the prepared BMI/T700 composite owns high toughness, excellent hot/wet properties and mechanical properties. The compression strength after impact (CAI) of 5428/T700 composite is 260 MPa, and the results of hot/wet test show that the long-term service temperature of 5428/T700 composite can maintain at 170 ℃.
2001 Vol. 17 (01): 17-18 [Abstract] ( 449 ) [HTML 1KB] [PDF 101KB] ( 516 )
19 J.C Huang
Recent Achievements in Developing Low Temperature and High Strain Rate Superplastic Materials
This paper is to briefly outline our recent activities in developing low temperature or high strain rate superplastic materials, including aircraft-used and general-purpose Al- and Mg-base alloys or composites, as well as Ti3AI base intermetallic alloys. The processing routes applied included the thermomechanical treatment, equal channel angular pressing and other extrusion or forging methods.
2001 Vol. 17 (01): 19-20 [Abstract] ( 343 ) [HTML 1KB] [PDF 222KB] ( 322 )
21 Mingyi ZHENG, Kun WU, Congkai YAO
Microstructure and Mechanical Behavior of Squeeze Cast SiCw/AZ91 Magnesium Matrix Composites
The interfacial microstructure and tensile properties of the squeeze cast SiCw/AZ91 Mg composites were characterized. There exist uniform, line and discrete MgO particles at the interface between SiC whisker and magnesium in the composites using acid aluminum phosphate binder. The interfacial reaction products MgO are beneficial to interfacial bonding between SiCw and the Mg matrix. resulting in an improvement of the mechanical properties of the composite.
2001 Vol. 17 (01): 21-22 [Abstract] ( 356 ) [HTML 1KB] [PDF 192KB] ( 365 )
23 Ye PAN, Guoxiong SUN
Sb-Mn Alloy in-situ Composites and Magnetic Properties
The microstructures and magnetic properties of two in-situ composites, directionally solidified Sb-9.5%Mn and Sb-50%Mn alloys, were investigated. The aligned ferromagnetic compound MuSb or Mn2Sb was embedded in Sb or Mn matrix with varying Mn content. The magnetization curves and thermal magnetic Curves were examined along solidification direction, which reveals the magnetic behaviors of the composites.
2001 Vol. 17 (01): 23-24 [Abstract] ( 351 ) [HTML 1KB] [PDF 181KB] ( 371 )
25 Wen WANG, Yu ZHOU, Sheng CHEN, Feng Y, Dechang JIA
Preparation of Strontium Bismuth Tantalum (SBT) Fine Powder by Sol-Gel Process Using Bismuth Subnitrate as Bismuth Source
Strontium bismuth tantalum (SBT) fine power was prepared by Sol-Gel method. Pentaethoxy tantalum, strontium acetate and bismuth subnitrate were used as raw materials, and were dissolved in proper order in ethylene glycol to form transparent sol. The mixed precursor was dried at 80℃ and annealed at 800℃ for 1 h. Crystallized nanometer sized SBT fine powder was obtained and characterized by XRD.
2001 Vol. 17 (01): 25-26 [Abstract] ( 366 ) [HTML 1KB] [PDF 87KB] ( 373 )
27 Eun-Kyung Lee, Hwan-Wook Ra, Kyo-Han Kim, Inn-Kyu Kang
Effect of Cross-linking Agent on Barbituric Acid-initiated Resin
To improve the tensile bond strength of denim bonding agents, the adhesion between denim and MMA resin was investigated by applying initiator systems containing 1-cyclohexyl-5-ethyl barbituric acid (CEB), copper acetyl acetonate (CAA), quaternary ammonium chloride (QAC). cupric ion, with the addition of TEGDMA, and pretreatment solution for denim, and an HEMA primer. The effects of a cross-linking agent on barbituric acid-initiated denim bonding resin were examined by measuring degree of conversion, molecular weight, hardness of bonding resin, and tensile bond strengths.
2001 Vol. 17 (01): 27-28 [Abstract] ( 451 ) [HTML 1KB] [PDF 125KB] ( 389 )
29 L.P. Wang, B. Y Tang, X.B. Tian, YX.Leng, Q. YZhang, P.K.Chu
Principle and Process Window of Cerium Dioxide Thin Film Fabrication with Dual Plasma Deposition
Cerium dioxide, CeO2, is a potentially superior material in a myriad of areas, and many methods have been proposed to deposit single crystal CeO2 thin films. A novel fabrication technique utilizing dual plasma generated by metal vacuum arc (MEVVA) and radio frequency (RF) is discussed in this paper. We have recently conducted a systematic investigation to determine the optimal process window to deposit CeO2 thin films'on Si(100) substrates. The X-ray diffraction results show the existence of CeO2(100) in the as-deposited sample
2001 Vol. 17 (01): 29-30 [Abstract] ( 386 ) [HTML 1KB] [PDF 129KB] ( 321 )
31 Yujin WANG, Yu ZHOU, Guiming SONG, Tingquan LEI
Elevated Temperature Strength of TiCp/W Composites
The elevated temperature mechanical properties of TiCp/W composites produced using powder metallurgical technique were investigated. Results show that with increasing temperature, the strength of TiCp/W composites increases gradually and reaches its maximum value at 1000℃, which is much higher than that at room temperature. The strengthening mechanisms at high temperature are attributed to dislocation strengthening and load transfer between matrix and particles.
2001 Vol. 17 (01): 31-32 [Abstract] ( 325 ) [HTML 1KB] [PDF 241KB] ( 294 )
33 Kyo-Han Kim, X.L.Zhu, Won-Woo Son, Yong-Soo Jeong
Formation and Morphology of Anodic Oxide Films of Ti
The morphology and structure of the oxide films of Ti in H3PO4 were investigated by galvanos tatic anodization, SEM and XRD. The oxide film grew from some pores in the grooves to layered microdomains as increasing anodizing voltage. The crystallinity of the oxide films decreased with the increase of the concentration of the electrolyte. The model has been proposed for the growth of the oxide films by two steps, i.e. by uniform thickening and by local deposition.
2001 Vol. 17 (01): 33-34 [Abstract] ( 385 ) [HTML 1KB] [PDF 186KB] ( 344 )
35 Congqin NING, Qingchang MENG, Yu ZHOU, Haitao LIU
Microstructure of Bioglass/Hydroxynpatite Coatings on Ti Substrate
Composite coatings of bioglass and hydroxyapatite (briefly named HA/BG) with different hydroxyapatite contents on titanium substrate were successfully fabricated. The fabricated coatings are characterized by rough and poriform surface.The densities of the coatings decrease with the increase of HA content. There is a transition layer with a 5 μm thickness between the BG coating and the substrate. During heat-treatment, hydroxyapatite crystals with hexastyle shape have precipitated from the BG.
2001 Vol. 17 (01): 35-36 [Abstract] ( 348 ) [HTML 1KB] [PDF 293KB] ( 346 )
37 Zhentao YU, Lian ZHOU, Haichen GU, Ju DENG
In-situ SEM Observation of Monotonic and Cyclic Deformed Structure in Ti-2A1-2.5Zr Alloy
The SEM observation in situ of monotonic and cyclic deformed structure in Ti-ZA1-2.5Zr alloy was performed. The regularity of slippage, crack nucleation, propagation and the typical dislocation configuration were also investigated. The twin and twist play an important role in maintaining homogeneous deformation in the final plastic deformation stage.
2001 Vol. 17 (01): 37-38 [Abstract] ( 362 ) [HTML 1KB] [PDF 278KB] ( 357 )
39 Jinghua YIN, Meicheng LI, Yufeng ZHENG, Zhong WANG, Wei CAI, Peilin WANG, Peilin WANG
Effect of Annealing Temperature on the Formation of Silicides and the Surface Morphologies of PtSi Films
The effect of annealing temperature on the formation of the PtSi phase. distribution of silicides and the surface morphologies of silicides films is investigated by XPS. AFM. It is shown that the phase sequences of the films change from Pt-Pt2Si-PtSi-Si to Pt+Pt2Si+PtSi-PtSi-Si or Pt+Pt2Si+PtSi-PtSi-st with an increase of annealing temperature and the reason for the formation of mixed layers is discussed.
2001 Vol. 17 (01): 39-40 [Abstract] ( 363 ) [HTML 1KB] [PDF 204KB] ( 331 )
41 X.B. Tian, L.P. Wang, D. T.K.Kwok, B. Y Tang, P.K.Chu
Capacitance of High-Voltage Coaxial Cable in Plasma Immersion Ion Implantation
Plasma immersion ion implantation (PIII) is an excellent technique for the surf see modification of complex-shaped components. Owing to pulsed operation mode of the high voltage and large slew rate, the capacitance on the high-voltage coaxial cable can be detrimental to the process and cannot be ignored. In fact, a significant portion of the rise-time/fall-time of the implantation voltage pulse and big initial current can be attributed to the coaxial cable.
2001 Vol. 17 (01): 41-42 [Abstract] ( 359 ) [HTML 1KB] [PDF 88KB] ( 510 )
43 Lin YANG, Zhentao YU, Ju DENG
Quick-homogeneous Corrosion of Ti-2A1-2.5Zr Alloy in High-temperature and High-pressure Water Steam
The corrosion behavior of Ti-2A1-2.5Zr alloy with 5 alloy contents and 5 surface states were studied in water steam at 400℃, 10.3 MPa for 72 h. The weight-increments of all samples are under 4 mg/dm2, better than Zr and Zr-alloy. α-Ti is oxidized into anatase-type TiO2 preferentially. The corrosion resistance is improved by adding Al element or pre-oxidizing treatment, the latter is more effective relatively.
2001 Vol. 17 (01): 43-44 [Abstract] ( 366 ) [HTML 1KB] [PDF 186KB] ( 364 )
45 D.Y.Li, X.Ma
Variations in Wear Resistance of a Novel Triboalloy Pseudoelastic TiNi Alloy-with Respect to its Pseudoelasticity and Hardness
It has recently been found that TiNt shape memory alloy has another attractive property, high resistance to wear. The wear resistance of this alloy benefits from its pseudoelasticity (PE). It has, however, been noticed that other mechanical properties also affect the wear resistance, especially the hardness. Research was conducted to investigate the correlation between the wear resistance and both the PE and hardness. It has been demonstrated that when the PE is high, lower hardness leads to higher wear resistance.
2001 Vol. 17 (01): 45-46 [Abstract] ( 365 ) [HTML 1KB] [PDF 176KB] ( 348 )
47 S. Chtchegolikhina
Investigation of Sintered Maraging Steels
Processing of five grades of sintered maraging steels containing 13% Cr, 9% Ni, 1% Ti and different quantities of Mo, Co is described. Variations of ageing temperatures and ageing holding times had resulted in choosing optimum regime of ageing f T=550℃, T=2.5 h. It allowed to receive mechanical properties of these steels like to them for compact steels, UTS=1200 MPa, EL=5.3%, RA=7%, and Charpy impact =1445 kJ/m2. X-ray analysis had shown phases Fe7Mo6, Fe2Mo in steels containing Co and decreasing of the period of α-phase lattice in these steels after ageing.
2001 Vol. 17 (01): 47-48 [Abstract] ( 377 ) [HTML 1KB] [PDF 72KB] ( 327 )
49 Qingfu CHEN, Liancheng ZHAO, R.Stalmans, J. Van Humbeeck
Influence of Isothermal Treatment on Superelastic Behavior of Cu-13.8Al-4.0Ni(mass fraction) Single Crystals
The superelastic behaviors of different isothermal treated Cu-13.SAl-4.ONi (mass fraction) single crystals were studied by applying tensile stress along <001> of the β phase. The different isothermal specimens have different superelastic behavior due to the change of the ratio of stress-induced γ1’and β’. The superelasticity ofγ1 phase tends to that of g, phase with cycling. Typical stabilization of stress-induced martensite above Ap results in residual deformation. Due to the reverse transformation of γ1’, there is a deviation of pseudo-yield stress form linear relation with temperature at relatively low stress.
2001 Vol. 17 (01): 49-50 [Abstract] ( 400 ) [HTML 1KB] [PDF 137KB] ( 270 )
51 Z.Wang, K.Dohda
Fatigue Behavior of Cemented Carbide Die in Cold Forging of Steel
The fatigue behavior of cemented carbide die under service load in the multistage cold forging of steel was investigated. It was found that the fatigue cracks do not initiate at the stress concentration position and the crack initiation position can be classified to three types. The crack initiation position can be predicted by FEM only when the plastic deformation of the die is considered.
2001 Vol. 17 (01): 51-52 [Abstract] ( 383 ) [HTML 1KB] [PDF 210KB] ( 463 )
53 Guangiiang YUAN, Yang ZHOU, Daming CHEN, Bangsheng LI
Preparation of Silicon Carbide with High Properties
In order to prepare silicon carbide with high properties, three kinds of SiC powders A, B, and C with different composition and two kinds of additives, which were Y2O3-A12O3 system and Y2O3-La2O3 system, were used in this experiment. The properties of hot-pressed SiC ceramics were measured. With the same additives, different SiC powder resulted in different properties. On the other hand, with the same SiC powder, increasing the amount of the additive Y2O3Al2O3 improved properties of SiC ceramics at room temperature, and increasing the amount of the additive Y2O3-La2O3 improved property SiC ceramics elevated temperature. In addition, the microstructure of SiC ceramics was studied by scanning electron microscopy.
2001 Vol. 17 (01): 53-54 [Abstract] ( 374 ) [HTML 1KB] [PDF 260KB] ( 335 )
55 Irina N.Mutilina
Development of Production Technology of Castle Composite Materials
The application of mechanical and chemical syntheses in an high-energy vibration mill of the FESTU makes easy the process of the introduction of reinforced powders in castle composite materials on the Al basis. The obtained reinforced phases of Al-Ti-C composition have high specific Surface due to peculiarities of explosive mechanical and chemical syntheses. It increases the uniformity of their distribution in a matrix melt during the mixing process and also increases properties of castle composite materials
2001 Vol. 17 (01): 55-56 [Abstract] ( 336 ) [HTML 1KB] [PDF 101KB] ( 288 )
57 Haitao FANG, Jingchuan ZHU, Zhongda YIN, Jae-Ho Jeon, Yoo-Dong Hahn
Preparation and Microstructure of a Si-Mo Fused Slurry Coating on Carbon/Carbon Composites for Oxidation Protection
A coating of composition Si-40Mo (wt pct) was prepared by fused slurry coating method on the two-dimensional carbon/carbon (2D-C/C) composite to improve oxidation resistance. In the procedure of the fabrication, pure St slurry inner layer in the pre-coating was necessary to apply because of infiltration of liquid Si into the substrate during the sintering. The coating consists of Si continuous phase and MoSi2 particles. In addition, the infiltration of Si into the substrate and the SiC reaction layer between the coating and the C/C composite were observed. Oxidation resistance and the thermal shock resistance of the Si-Mo fused sluury coating were quite excellent at 1730℃
2001 Vol. 17 (01): 57-58 [Abstract] ( 360 ) [HTML 1KB] [PDF 125KB] ( 388 )
59 M.D.Starostenkov, G.M.Poletayev, D.M.Starostenkov
Structure of Interphase Boundaries in Bimetallic Thin Films
The structural transformation in thin films of bimetals in the dependence on temperature and concentration of vacancies was investigated. The system Ni-Al structural transformation was realized by computer design according to the mechanism of self-sustained high-temperature synthesis. Structural transformation is characterized by the presence of dislocations, clusters of point defects and germs of intermetallic phases near interphase boundaries.
2001 Vol. 17 (01): 59-60 [Abstract] ( 362 ) [HTML 1KB] [PDF 123KB] ( 268 )
61 Gaohui WU, Bofeng LUAN, Longtao JIANG, Dougli SUN
Effect of Thermal Cycling Treatment on Microstructure and Mechanical Properties of AlNp/2024A1 Composite
The A1NP/2024 composite with a high volume fraction (50%) was fabricated by squeeze casting. Its mechanical properties were investigated by tensile tests at ambient temperature and the microstructure was observed by a transmission electron microscope (TEM). It was indicated that after six thermal cooling cycles treatment the AIN/2024Al composite exhibited higher elastic limit (ac.ol), tensile strength (UTS) and elastic modulus (E). TEM observation showed that there was higher dislocation density both in the matrix and the particle. Δ’ phase is the mainly precipitate
2001 Vol. 17 (01): 61-62 [Abstract] ( 405 ) [HTML 1KB] [PDF 246KB] ( 355 )
63 A.A.Popovich, V P.Reva, T.A.Popovich, O.V Arestov
Kinetics and Structure of Refractory Compounds and Alloys Obtained by Mechanical Alloying
Refractory compounds are material with interesting properties for structural applications. However, the processing of Such material is a great challenge because of their high melting temperature and limited ductility. Mechanical alloying is a novel technique of producing refractory compounds with specific properties. Kinetical and structural peculiarities of refractory compounds and alloys obtained by mechanical alloying are discussed.
2001 Vol. 17 (01): 63-64 [Abstract] ( 360 ) [HTML 1KB] [PDF 113KB] ( 289 )
65 Weifang ZHANG, Niansheng XI, Chunhu TAO, Jiecai HAN, Shanyi DU
Microstructure and Resisting Thermal Shock Behaviors of TiC-Al2O3/Fe Functionally Graded Materials Prepared by SHS/PHIP
The microstructure and composition of TiC-A12O3/Fe functionally graded materials (FGM) prepared by self-propagating high temperature synthesis and pseudo-hot isostatic pressing (SHS/ PHIP) were studied, and the resisting thermal shock behaviors were analyzed. The results show that TiC-A12O3/Fe FGM has graded composition distribution. No cross-section crack through the layers was found in the tests of thermal shock and fatigue.
2001 Vol. 17 (01): 65-66 [Abstract] ( 362 ) [HTML 1KB] [PDF 200KB] ( 343 )
67 Daming XU, Guangju SI, Geying AN, QingChun LI
Numerical Simulation of Transport Phenomena in Solidification of Multicomponent Ingot Using a Continuum Model
A continuum model proposed for dendrite solidification of multicomponent alloys, with any partial solid back diffusion, was used to numerically simulate the macroscopic solidification transport phenomena and macrosegregations in an upwards directionally solidified plain carbon steel ingot. The computational results of each macroscopic field of the physical variables involved in the solidification process at a middle solidification stage were presented.
2001 Vol. 17 (01): 67-68 [Abstract] ( 366 ) [HTML 1KB] [PDF 146KB] ( 323 )
69 Geying AN, Xun SUN, Junqing WANG
Turbulent Fluid Flow and Heat Transfer Calculation in Mold Filling and Solidification Processes of Castings
Based on the time-averaging equations and a modified engineering turbulence model, the mold filling and solidification processes of castings are approximately described. The algorithm for the control equations is briefly introduced, and some problems and improvement methods for the traditional method are also presented. Both calculation and tests proved that, comparing with the laminar fluid flow and heat transfer, the simulation results by using the turbulence model are closer to the real mold filling and solidification processes of castings.
2001 Vol. 17 (01): 69-70 [Abstract] ( 367 ) [HTML 1KB] [PDF 92KB] ( 632 )
71 Yuyong CHEN, Xiumei QI, Xuezhu MA, Huiguang WANG, Jing TIAN
Sinterability of Zirconia Top Coat of Investment Mold for Ti Alloy
In this paper, zirconia is used as top mold material for Ti investment casting. Top mold samples are made by proper mold building technology. The effect of different sintering temperature on chemical composition, microstructure and residual bending strength of the top mold sample is studied. The volume and homogeneity of the air holes in the top mold are determined by sintering temperature, and finally determined the residual bending strength of the mold sample was determined.
2001 Vol. 17 (01): 71-72 [Abstract] ( 415 ) [HTML 1KB] [PDF 233KB] ( 360 )
73 Yanxiang LI, Xiao HU, Xuerong XU
Pattern Recognition of Thermal Analysis Cooling Curves and Quality Evaluation of Melt Cast Alloys
The development of thermal analysis techniques for evaluation of cast alloy melt quality and its current applications in the foundry were reviewed. The characteristics of the current thermal analysis techniques were analyzed. A new comprehensive method for cooling curve recognition has been proposed. The evaluation of cast alloy melt quality was realized.
2001 Vol. 17 (01): 73-74 [Abstract] ( 376 ) [HTML 1KB] [PDF 94KB] ( 467 )
75 Jingjie GUO, Yuan LIU, Hongsheng DING, Yanqing SU, Jun JIA
Optimum Design of Processing Parameters during ISM Process of Ti-47Ni-9Nb
Using direct finite difference method, a numerical model for simulating the temperature field in the charge during induction skull melting (ISM) has been developed. On the basis of the model, the temperature field in Ti- 47Ni-9Nb ingot has been calculated under various melting conditions. Finally, the processing parameters (melting power, melting-down time and the final melt temperature) have been optimized.
2001 Vol. 17 (01): 75-76 [Abstract] ( 338 ) [HTML 1KB] [PDF 98KB] ( 338 )
77 Dong LI, Zhentao YU, Weisheng TANG, Ju DENG
A New α Ti Alloy (Ti-4Al-2V) for Marine Engineering
NIN has developed a new type of Ti alloy. It is suitable for structure pieces applied in high-temperature and high-pressure water/steam conditions. Its nominal composition is Ti-4Al-2V. In this paper, its microstructure, mechanical properties and corrosion resistance were studied in detail.
2001 Vol. 17 (01): 77-78 [Abstract] ( 387 ) [HTML 1KB] [PDF 135KB] ( 337 )
79 Jun SHEN, Zhuangde XIE, Bide ZHOU, Qingchun LI, Zhijun SU, Hongsheng LE
Characteristics and Microstructure of a Hypereutectic Al-Si Alloy Powder by Ultrasonic Gas Atomization Process
A hypereutectic Al-Si alloy powder was prepared by ultrasonic gas atomization process. The morphologies, microstructure and phase constituent of the alloy powder were studied. The results showed that powder of the alloy was very fine and its microstructure was mainly consisted of Si crystals plus intermetallic compound A19FeSi3, which were very fine and uniformly distributed.
2001 Vol. 17 (01): 79-80 [Abstract] ( 350 ) [HTML 1KB] [PDF 221KB] ( 440 )
81 Guanghui MIN, Shuqi ZHENG, T.Inoue, K. Ueno
Fracture Behavior of Alumina-based Prismatic Ceramic Composites
The fracture toughness and fracture work of A12O3/SiC prismatic ceramic composites was evaluated in this paper, which showed the fracture energy was improved greatly. Based on the observation for crack propagation and fracture morphology, the fracture behavior of the prismatic composites was analyzed. In the bending test, the composites displayed a non-catastrophic behavior and a graceful failure with reasonable load-carrying capability.
2001 Vol. 17 (01): 81-82 [Abstract] ( 353 ) [HTML 1KB] [PDF 147KB] ( 311 )
83 Yanqing SU, Jingjie GUO, HongSheng DING, Songqing LIU, Yuan LIU, GuiZhong LIU, Jun JIA
Component Evaporation of Ti-15-3 Melt during ISM Processing
How to control melt composition is the key for getting high quality alloy melt. The paper made the following efforts: (1) The activity coefficients in Ti-15-3 melt have been calculated. (2) Taking advantage of the activity coefficients, the evaporation losses of components in Ti-15-3 melt during ISM process have been studied. The calculated results show that there is a critical vacuum degree (about 1.33 Pa) during melting process.
2001 Vol. 17 (01): 83-84 [Abstract] ( 367 ) [HTML 1KB] [PDF 99KB] ( 346 )
85 Sen YANG, Yunpeng SU, Zhenxia LIU, Weidong HUANG, Yaohe ZHOU
Cellular Spacing Selection of Cu-Mn Alloy under Ultrahigh Temperature Gradient and Rapid Solidification Condition
Cellular spacing selection of Cu-27.3 wt pct Mn alloy has been investigated by laser surface rapid resolidification experiments. The experimental results show that there exists a wide distribution range in cellular spacing under ultra-high temperature gradient and rapid solidification conditions and the average spacing decrease with increase of the growth rate. The experimental results are compared with the current KGT model for rapid cellular/dendritic growth, and a reasonable agreement is found.
2001 Vol. 17 (01): 85-86 [Abstract] ( 360 ) [HTML 1KB] [PDF 177KB] ( 326 )
87 Chengsong CUI, Fuyang CAO, Zhenyu LI, Qingchun LI
Modeling of Heat Transfer and Solidification of Composite Roll
Modeling of heat transfer and solidification of composite roll was established and used to predict the thermal history and solidification process of roll during spray forming. Evolution of temperature field of the preform and cooling rate in the growing deposit during spray deposition and post-deposition were numerically simulated.
2001 Vol. 17 (01): 87-88 [Abstract] ( 346 ) [HTML 1KB] [PDF 71KB] ( 331 )
89 Wanming ZHANG, Wei DU, Hengzhi FU
Effect of Solidification Condition on Microstructure and Mechanical Properties of Single Crystal Superalloy
CMSX-2 single crystals with different primary dendrite arm spacing were obtained on directional solidification apparatus with high temperature gradient (250 K/cm). The microstructure and elevated temperature stress rupture properties of these single crystals were examined and analyzed.
2001 Vol. 17 (01): 89-90 [Abstract] ( 354 ) [HTML 1KB] [PDF 441KB] ( 391 )
91 Xuezhu MA, Jun SHEN, Xiumei QI, Jun JIA
Cooling Rates of PREP Ti48Al Alloy
Determining the cooling rate of a rapidly-solidified (RS) technique subjectively is a prerequisite of knowing the RS technique, and it is difficult. Model of heat transfer is constructed in this paper in order to calculate cooling rates of rapidly-solidified Ti48AI alloy. Rapid solidification technique utilized is the plasma rotating electrode process (PREP hereafter). The results show that: the cooling rate of PREP is at the scope of 102-103 K/s.
2001 Vol. 17 (01): 91-92 [Abstract] ( 372 ) [HTML 1KB] [PDF 111KB] ( 379 )
93 Xuelei TIAN, Xichen CHEN
Correlation between Structures of Bulk Amorphous Zr-Ti-Ni-Cu-Be Alloy in Different States
The structures of the bulk amorphous Zr41Ti14Cu12.5Nil0.0Be22.5 alloy have been analyzed in solid, supercooled liquid and liquid with X-ray diffraction. The first coordination sphere radii and the first coordination numbers are 0.312 um, 11.2 in solid state, 10.932 nm, 10.932 in supercooled liquid region and 0.305 urn, 11.296 in liquid state. The structures are the same in different states. But it shows some tendency to crystallizing that the first coordination sphere radius and the first coordination number drop in supercooled liquid region.
2001 Vol. 17 (01): 93-94 [Abstract] ( 359 ) [HTML 1KB] [PDF 70KB] ( 313 )
95 Xiang XUE, Zhiliang NING, Bide ZHOU, Chunhui ZHANG
Numerical Simulation of Temperature Field of Die Casting Dies
In this study, the Solidworks was used as pre-processor, which performed the three- dimensional solid construction and automatic enmeshment. The COSMOS was adopted as post- processor to display the temperature distribution and further to simulate the thermal stress distribution of dies. A software package for three-dimensional temperature fields of complicated die casting and its dies was developed and the temperature distributions of a fan cover casting were simulated by the software.
2001 Vol. 17 (01): 95-96 [Abstract] ( 378 ) [HTML 1KB] [PDF 84KB] ( 429 )
97 Jinjiang YU, Jun ZHANG, Hengzhi FU, Jinchen ZHAO
Microstructure Characteristics of Ni-Nb Near Eutectic Alloy during EBFZM Directional Solidification
Microstructure Characteristic of Ni-Nb near eutectic alloy is systematically investigated during directional solidification with electron beam floating zone melting (EBFZM). The effect of the Zone melting rate on the microstructure has also been studied.
2001 Vol. 17 (01): 97-98 [Abstract] ( 368 ) [HTML 1KB] [PDF 256KB] ( 296 )
99 Hongsheng DING, Jun JIA, Jingiie GUO, Yanqing SU, HengZhi FU, Jinshan LI
Thermodynamic Analysis on Interaction between Molten Ti Alloys and Oxide Molding Materials
A thermodynamic model has been built up for the interactions between molten Ti alloys and oxide molding materials in the way of decomposition and solution of molding materials, then the influences on the reaction free energy changes have been calculated and discussed.
2001 Vol. 17 (01): 99-100 [Abstract] ( 369 ) [HTML 1KB] [PDF 87KB] ( 323 )
101 Fuyang CAO, Chengsong CUI, QingChun LI
Modeling of Heat Transfer and Solidification Process of Spray Formed Billet
In this paper, modeling of heat transfer and solidification process of spray formed billet was established. Thermal profiles of billet at various spray time and under various spray forming conditions were calculated numerically. The simulation results are consistent with the actual experimental results.
2001 Vol. 17 (01): 101-102 [Abstract] ( 371 ) [HTML 1KB] [PDF 77KB] ( 399 )
103 Bo YANG, Erlin ZHANG, Yunxue JIN, Zhaojun ZHU, Songyan ZENG
Microstructure Characteristic of In-situ Ti/TiC Composites
TiC reinforced titanium composites has been produced with different Al content and C content by XDTM. The results have shown that TiC particles are of two different morphologies f coarse dendritical primary TiC and short bar-shape eutectic TiC. Al content has great effects on the morphology of TiC. With the increasing of Al content, the morphology of primary TiC changes from coarse developed dendrite into short bar-shape or plate--shape TiC with 35%Al. Meanwhile, the structure of the matrix changes from single Ti to Ti and Ti2Al and to Ti3Al. However, the C content has no influence on the microstructure of matrix. When the C content is less than 1.2%, the dendrite TiC disappears and only short bar-shape or plate-shape TiC exists in the composites. In addition, the effect of heat of heat treatment on the morphology of TiC has also studied.
2001 Vol. 17 (01): 103-104 [Abstract] ( 346 ) [HTML 1KB] [PDF 245KB] ( 360 )
105 Jianfei SUN, Jun SHEN, Fuyang CAO, Qingchun LI
Nucleation and Growth of Atomizing Droplets during Spray Forming
In this paper, the behaviors of nucleation and growth of atomizing droplets were investigated by means of microstructure observation and theoretical analysis. The results showed that, there is a unique heterogeneous nucleation mechanism for atomizing process that pre-solid smaller particles colliding with and embedding in liquid-state larger ones act as heterogeneous nuclei. In addition, the reasons of presenting the dendritic growth was analyzed based on the nonequilibrium solute distribution theory, and the relationship between the microstructural refinement and the cooling rate of the material was given.
2001 Vol. 17 (01): 105-106 [Abstract] ( 379 ) [HTML 1KB] [PDF 217KB] ( 325 )
107 Hu ZHANG, Guowei CHANG, Hanqi HU
Model of Stabilizing Continuous Unidirectional Solidification Process
The relation of the related parameters concerning the continuous unidirectional solidification process is derived by means of the theoretical analysis of the heat transfer, the theoretical model is verified by experiments.
2001 Vol. 17 (01): 107-108 [Abstract] ( 313 ) [HTML 1KB] [PDF 67KB] ( 321 )
109 Yuebing ZHANG, Xiang XUE, Bide ZHOU
Numerical Simulation and Water Analog of Mold Filling Processes
This paper demonstrates the potential of a computer code, developed by the authors, in shaping gating systems by modeling the fluid flow phenomena through a complex gating system during mold filling. A plate casting with dimension 200 mm×200 mm×50 mm was chosen as the verifying problem. Water analog studies were carried out on this casting. The comparison indicates that computer simulation could be a powerful tool in shaping gating systems.
2001 Vol. 17 (01): 109-110 [Abstract] ( 379 ) [HTML 1KB] [PDF 101KB] ( 315 )
111 E. Chumachenko, M.Tsepin, A.Tchekine, O.Panina
Calculation of Structural Characteristics Evolution during Superplastic Forming of Shells by
The applications of commercial computer program set "SPLEN-O" based on finite elements method (FEM) for the simulation of superplastic forming (SPF) technology of shells are described. The changes in characteristics of ultrafine-grained (UFG) structure during deformation are taken into account in function of viscosity and solving algorithm. Some examples are shown to illustrate the possibilities of FEM simulation for prediction of numerical grain-size data on different SPF stages of shells.
2001 Vol. 17 (01): 111-112 [Abstract] ( 372 ) [HTML 1KB] [PDF 95KB] ( 286 )
113 Shihong ZHANG, Yi XU, Yangling SHANG, Ke YANG, Zhongtang WANG
Lubrication in Hot Tube Extrusion of Superalloys and Ti Alloys
Tubular products made of superalloys and titanium alloys usually work in high temperature environment and applied heavy loading. Hot extrusion is the best technology to form tubular billets with fine microstructures and good mechanical properties. Lubrication is one of the key techniques in hot extrusion, glass lubricants are most suitable for hot extrusion. Lubrication technique in hot extrusion is dealt with in this paper, the lubrication principle of hot tube extrusion is presented. Experiments of glass lubricated backward tube extrusion of titanium alloys and forward tube extrusion of superalloys are also dicussed.
2001 Vol. 17 (01): 113-114 [Abstract] ( 441 ) [HTML 1KB] [PDF 75KB] ( 907 )
115 A.T.Male, Y.W.Chen, P.J.Li, C.Pan, Y.M.Zhang
Plasma-Jet Forming of Sheet Metal Shapes
Plasma-jet forming is a newly proposed flexible sheet metal forming process. A non-transferred arc plasma torch is used as a controllable heat source to produce internal stress in sheet metals, causing plastic deformation without the necessity of hard tooling. This method has potential for rapid prototyping of sheet metal parts by reducing development costs and lead times. A robotic system has been used to perform simple linear bends in several different alloys. In order to develop a controllable process and to improve the forming accuracy, the effects of various process parameters on the obtained shape changes and ton the resulting structure and properties have been studied. The overall goal is to understand the roles of the forming parameters and their inter-relationship in optimizing the forming procedure-a high forming speed without damage to the material structure or properties.
2001 Vol. 17 (01): 115-116 [Abstract] ( 372 ) [HTML 1KB] [PDF 75KB] ( 414 )
117 Zhiheng ZHAO, Chunfeng LI, YongZhi WANG, Yuying YANG
Optimum Location of Tube Blank in Electromagnetic Bulging
Using analytical method, this paper gets 'the mutual inductance between coil and workpiece in tube blank electromagnetic bulging. According to this, we obtain the optimum locations of tube blank with different length of coil and workpiece. There is a good agreement between results calculated and the experimental data.
2001 Vol. 17 (01): 117-118 [Abstract] ( 351 ) [HTML 1KB] [PDF 58KB] ( 331 )
119 Hanliang ZHU, Zhiqiang LI, Bosheng SHANG, Wenfeng MAO, Chunxiao WANG, Shiqiong LI, Jianwei ZHANG
Superplasticity of a Ti-24Al-14Nb-3V-0.5Mo Intermetallic Alloy
Superplastic properties and microstructural evolution of a Ti-24Al-14Nb-3V-0.5Mo (at. pct) intermetallic alloy were studied. Optimum superplastic properties were obtained for temperatures in the interval 960℃≤5 T≤5980℃. The apparent activation energy in the superplastic regime was determined and the deformation mechanism was also discussed. Based on the studies, a curve panel with three sheets sandwich structure was fabricated successfully. The microstructures corresponding to different strain in the part were also studied.
2001 Vol. 17 (01): 119-120 [Abstract] ( 358 ) [HTML 1KB] [PDF 208KB] ( 293 )
121 Guofeng WANG, Kaifeng ZHANG, Dezhong WU
Application of Fractal Theory in the Synthesis of Nano-sized 3Y-TZP Superplastic Ceramic Materials
Nano-sized 3Y-TZP powders were Synthesized by two methods. A fractal software was developed. A new and convenient method for characterizing the quality of Synthetic process by using fractal theory was obtained.
2001 Vol. 17 (01): 121-122 [Abstract] ( 354 ) [HTML 1KB] [PDF 80KB] ( 338 )
123 Andrei N.Yershov, Jeong Seung
Rheology of superplastic ceramics
Constitutive equation of rheology describing a phenomenological level of superplastic deformation as functional correlation between tensor components of stress and strain rate has been analyzed for the case of superplastic ceramic flow. Rheological properties of material are taken into account by means of scalar rheological coefficients of shear and volume viscosity, which are functions of temperature, effective stress (or strain rate) and density of material.
2001 Vol. 17 (01): 123-124 [Abstract] ( 361 ) [HTML 1KB] [PDF 95KB] ( 345 )
125 Debin SHAN, Yan LU, Ping LI, Yi XU
Key problems of cold power spinning of Ti-15-3 alloy
The key problems of cold power spinning of Ti-15-3 alloy are studied. Reasonable biller preparation methods are presented to improve crystal structure and avoid crack of billet. Influences of original wall thickness, reduction rate and feed rate on expanding in diameter are analyzed and some methods to prevent expanding in diameter are given.
2001 Vol. 17 (01): 125-126 [Abstract] ( 358 ) [HTML 1KB] [PDF 138KB] ( 331 )
127 T. Umemura, Y.Zhou, S.Kamimura, N.Motoi, Y Ohta, N. Yamaguchi
Die motions of new forging process using intermediate die assembly
The die motions of a new forging process for automation with an intermediate die assembly called hamburger were analyzed through high-speed video pictures. The results showed that the upper die that is assembled in the hamburger and retained over the lower die collides few times with the ram and workpiece, but sound products can be obtained with less sticking in spite of the lowered impacts of hit.
2001 Vol. 17 (01): 127-128 [Abstract] ( 355 ) [HTML 1KB] [PDF 84KB] ( 304 )
129 Gang LIU, Shijian YUAN, Mingxue ZHANG, Longbiao CHI
Numerical analysis on rotary forging mechanism of a flange
A numerical simulation on the rotary forging process of a flange is conducted by three-dimensional rigid-plastic finite element method. The states of stress and strain rate in the workpiece are analyzed and the forging mechanism of the flange is revealed. Moreover, the influence of the die configuration on the material flow is also analyzed.
2001 Vol. 17 (01): 129-130 [Abstract] ( 362 ) [HTML 1KB] [PDF 81KB] ( 435 )
131 Yongming KONG, Xianbin ZHOU, Min LI
Numerical analysis of hydroforming deep drawing of conical cup
Aided by the FE-code, analysis is carried to find the proper hydroforming deep-drawing condition for the perfect forming of a conical cup that can not be drawn successfully by conventional deep drawing method. Hydraulic counter pressure must be reasonably controlled, otherwise defects such as fracture and wrinkling can not be avoided. Therefore, the forming procedure is divided into three stages, and the counter pressure is adjusted intentionally to make the blank clamped onto the punch at a suitable time, then deformation at dangerous area is resisted by the effect of the counter pressure and the conical cup can be formed without defects.
2001 Vol. 17 (01): 131-132 [Abstract] ( 376 ) [HTML 1KB] [PDF 144KB] ( 457 )
133 Lihui LANG, Dachang KANG, Zhongren WANG, Shijian YUAN
Numerical simulation of failure during cylindrical cup hydrodynamic deep drawing
In this paper, a method to combine the mathematical analytic equation and general FEM software has been applied in the simulation of hydrodynamic deep drawing (HDD) cylindrical cup, also the failure types such as fracture and wrinkling are studied and solved. The simulated results are coincided with experimental results.
2001 Vol. 17 (01): 133-134 [Abstract] ( 352 ) [HTML 1KB] [PDF 137KB] ( 423 )
135 He YANG, Zhichao SUN
Effect of deformation condition on axial compressive precision forming process of tube with curling die
The effect of the deformation condition on the axial compressive precision forming process of tube with curling die was investigated by using a rigid-plastic FEM. The results show that the forming accuracy depends mainly on geometric condition r(ρ)/d(0), little on tube material properties and friction condition, the relative gap Delta /2r(ρ) of double-walled tubes obtained decreases with increasing r(ρ)/d(0), and there is a parameter k for a given t(0)/d(0) or r(ρ)/t(0), when r(ρ)/d0 > k, Delta /2r(ρ) < 1, otherwise /2r(ρ) > 1.
2001 Vol. 17 (01): 135-136 [Abstract] ( 323 ) [HTML 1KB] [PDF 79KB] ( 335 )
137 Xuechun LI, Yyying YANG, Zhaohai JIN, Junting LIU, Shunping LI
Application of neural network in precision prediction of hat-section profiles in rotary draw bending
It is difficult to control the accuracy of hat-section profile rotary-draw bent products because their shapes are complex and many factors influence the forming process. In this paper, a multi-layer feed-forward neural network based on improved BP (back propagation) algorithm is adopted to study the influence law of the main material properties and forming parameters on the accuracy of hat-section profile forming process. Rotary draw-bending precision prediction is realized and the technology parameters in the forming process are controlled according to the given precision.
2001 Vol. 17 (01): 137-138 [Abstract] ( 388 ) [HTML 1KB] [PDF 70KB] ( 298 )
139 Guoqun ZHAO, Xue DENG
Buster die shape design of a track link forging using FEM based back-tracing method
For the preform design of a complex track link forging, fifteen critical sections were selected for two dimensional back-tracing using FEM. The preform shapes of the critical sections are designed and integrated into an ideal 3D busting shape. The buster dies are finally designed according to the ideal busting shape with a little of modification. The 3D simulation of the busting stage is carried out.
2001 Vol. 17 (01): 139-140 [Abstract] ( 332 ) [HTML 1KB] [PDF 153KB] ( 498 )
141 Hyunsung Sou, Youngsuk Kim, Youngsuk Kim
Calculations of forming limit diagrams for changing strain paths on the formability of sheet metal
In the press shop of most sheet metals, sheet material undergoes complex strain path and also the formability of the sheet material was limited by the stretchability of the material. Therefore, the precise prediction of path-dependent FLD based on M-K approach using generalization of Hill's 1979 anisotropic yield criterion and introducing a strain gradient effect in the constitutive equation. Also, the theoretically obtained FLD will be compared with experimental data for steel sheets.
2001 Vol. 17 (01): 141-142 [Abstract] ( 344 ) [HTML 1KB] [PDF 108KB] ( 491 )
143 Zuocheng WANG, Fang WANG
Properties, microstructures and precipitate morphology of hot-rolled interstitial-free (IF) steel sheets
In order to simplify production process and to decrease production cost of thicker cold-rolled IF steel sheets for deep drawing applications, a new hot-rolled IF steel sheet is developed through hot-rolling in alpha region. In this paper, properties, microstructures and precipitate morphology of hot-rolled IF steel sheets are described.
2001 Vol. 17 (01): 143-144 [Abstract] ( 366 ) [HTML 1KB] [PDF 190KB] ( 554 )
145 Youngsuk Kim, Dongyoul Choi, Sungyeun Won
Molecular dynamics simulation for grain boundary deformation under tensile loading condition
In this study, MD simulations have been performed to observe the behavior of a grain boundary in an alpha -Fe plate under 2-dimensional loading. In MD simulation, the acceleration of every molecule can be achieved from the potential energy and the force interacting between each molecule, and the integration of the motion equation by using Verlet method gives the displacement of each molecule. Initially, four α-Fe rectangular plates having different misorientation angles of grain boundary were modeled by using the Johnson potential and Morse potential. We compared the potential energy of the grain boundary system with that of the perfect structure model. Also, we could obtain the width of the grain boundary by investigating the local potential energy distribution. The tensile loading for each grain boundary models was applied and the behavior of grain boundary was studied. From this study it was clarified that in the case using Johnson potential, the obvious fracture mechanism occurs along the grain boundary, in the case of Morse potential, the diffusion of the grain boundary appears instead of the grain boundary fracture.
2001 Vol. 17 (01): 145-146 [Abstract] ( 330 ) [HTML 1KB] [PDF 155KB] ( 382 )
147 Fuxiao CHEN, Juanhua SU, Yunlin YANG, Hongtao MA
Research on superplasticity and superplastic extrusion of MB26 magnesium alloy
The superplastic flow characteristics of hot extruded MB26 Mg alloy under the conditions of tension are studied. The effects of deformation temperature and strain rate on superplasticity are analyzed. On the other hand, the superplastic extrusion of MB26 Mg alloy is also studied.
2001 Vol. 17 (01): 147-148 [Abstract] ( 395 ) [HTML 1KB] [PDF 111KB] ( 339 )
149 Bin GUO, Xiaodong XING, Huming DAI, Ronghua LUO, Zhongren WANG
A special device for viscous pressure forming: Design and implementation
A flexible special device for viscous pressure forming is designed and implemented. By using three proportional electro-hydraulic relief valves connected to a computer for precise control of releasing pressure of the medium, we can form differential pressure distribution in the die cavity. With the cooperation of programmable logical controller (PLC), computer and sensor modules in control system the device can satisfy all the requirements of the new forming process.
2001 Vol. 17 (01): 149-150 [Abstract] ( 375 ) [HTML 1KB] [PDF 84KB] ( 348 )
151 Weilu WU, Zhentao YU, Ju DENG
Investigation on relationships among deformation, texture and properties of TA16 alloy tube
The relationships among the deformation, texture and properties of TA16 alloy tube were investigated, an optimum processing parameter was obtained. High Q (the ratio of reduction of diameter to reduction of wall thickness) values increase tensile, flaring properties and reduce flattening, high Q values increase tensile strength, flattening, flaring, and decrease tensile elongation. The main circular textures of rolling tubes are basal (0001) and pyramidal {10(1) over bar 5}, {10(1) over bar 4}, {10(1) over bar 3)}etc., and the main axial textures are prism {10(1) over bar 0} and pyramidal {11(2) over bar 0}, {21(3) over bar 1}, {20(2) over bar 1} etc, under different Q and epsilon values. There are greater changes in the grain size under different epsilon values, compared with that under different Q values.
2001 Vol. 17 (01): 151-152 [Abstract] ( 381 ) [HTML 1KB] [PDF 192KB] ( 330 )
153 Hongyi SUN, Yu CHEN, Dachang KANG
Application on the "shear-extrusion" process to form large-size high-pressure valve bodies
This paper describes a new metal plastic forming process named "shear-extrusion" The new process is studied by using numerical analysis and experiment methods, and applied to form large-size high pressure valve bodies used by power plant boiler. Finally, the valve bodies have been successfully formed on the 10000 kN screw press.
2001 Vol. 17 (01): 153-154 [Abstract] ( 364 ) [HTML 1KB] [PDF 126KB] ( 329 )
155 Jun LU, Zhongjin WANG, Mingxue ZHANG
Influence of friction condition on cold upsetting of tube flange
FEM is used to analyze the influence of interface friction on the material flow and the cause of forming defect in the cold upsetting of tube flange. Based on the FEM simulation results, the relationships between flange width and the extreme friction factors are established. The concept of forming limit diagram for cold upsetting of tube flange is presented.
2001 Vol. 17 (01): 155-156 [Abstract] ( 342 ) [HTML 1KB] [PDF 113KB] ( 455 )
157 Zhenxiou HOU, Bugeng TENG, Jun LU, Zhubin HE, Zhongren WANG
An experimental study of bulge-forming polycarbonate (PC) semisphere shell parts
In this paper, a new bulge-forming technology is described to manufacture a polycarbonate semisphere shell. Some experiments have been done, and the experimental results show that this technique is feasible to form polycarbonate part. But the wall thickness distribution of the bulged specimen by this method is not so even.
2001 Vol. 17 (01): 157-157 [Abstract] ( 383 ) [HTML 1KB] [PDF 33KB] ( 343 )
158 Hongyang LI, Shijian YUAN, Kun DAI, Lihui LANG, Xiaosong WANG, Zhubin HE, Zhongren WANG
Effect of loading paths on hydroforming tubular square components
The influence of loading path on tube hydroforming process is discussed in this paper with finite-element simulation. Four different loading paths are utilized in simulating the forming process of square tubular component with hydroforming and the result of different loading path is presented. Among the result, the thickness distribution of bilinear loading path is the most uniform one. It shows that the increase of punch displacement in the stage of high pressure is beneficial to the forming of component for optimized stress condition.
2001 Vol. 17 (01): 158-158 [Abstract] ( 360 ) [HTML 1KB] [PDF 54KB] ( 332 )
159 Yuming ZHANG, Shaobin ZHANG, bang JIANG, Lin WU
Keyhole double-sided arc welding process
In the proposed method, the current/arc is guided through the keyhole so that the energy of the plasma jet is compensated while it is consumed in heating the workpiece along the keyhole. As a result, deep narrow penetration has been achieved on 12.7 mm (1/2 ") thick stainless steel plates using 70 A welding current.
2001 Vol. 17 (01): 159-160 [Abstract] ( 365 ) [HTML 1KB] [PDF 126KB] ( 345 )
161 Jinsong TIAN, Lin WU, Ming DAI, Yu KONG
A general algorithm of rotating/tilting positioner inverse kinematics for robotic arc welding off-line programming
Off-line programming provides an essential link between CAD and CAM, whose development should result in greater use of robotic are welding. An are welding system with a robot and a rotating/tilting positioner is a major application area, where manual programming is a very tedious job. Off-line programming is a constructive way to solve the problem. The inverse kinematics algorithm of robot and positioner is the foundation of the off-line programming system. Although previously there were some researchers who studied the positioner inverse kinematics algorithm, they only focused on a special solution of the positioner inverse kinematics, which is the solution at down-hand welding position. However, in welding production, welding position other than down-hand position is also needed. A method for representing welding position was introduced. Then a general algorithm of rotating/tilting positioner inverse kinematics is presented.
2001 Vol. 17 (01): 161-162 [Abstract] ( 351 ) [HTML 1KB] [PDF 56KB] ( 470 )
163 Shaoqing GUO, Xiaohong LI, Wenli XU, Xuesong LIU, Xin WAN, Xitang TIAN
Welding distortion control of thin Al alloy plate by static thermal tensioning
The mechanism and effectiveness of welding distortion mitigation by static thermal tensioning were investigated by both finite element analysis and experiments. It shows that preset thermal tensioning can reduce longitudinal plastic compression remained in the weld and its adjacent zone significantly, so decrease the longitudinal residual stress and the susceptibility to welding distortion.
2001 Vol. 17 (01): 163-164 [Abstract] ( 347 ) [HTML 1KB] [PDF 70KB] ( 438 )
165 Hongyuan FANG, Li WANG, Yiyu QIAN
Life prediction of ball grid array soldered joints under thermal cycling loading by fracture mechanics method
Fatigue crack propagation life of ball grid array (BGA) soldered joints during thermal cycling loading was investigated by fracture mechanics approach using finite element analysis. The relationships between the strain energy release rate (G) acid crack size (a), thermal cycle numbers (N) can be derived. Based on the relationships, fatigue life of the soldered joints was determined. The results showed that crack propagation life was higher than crack initiation life. Therefore, it appears that it is more appropriate to predict the fatigue life of soldered joints using the fracture mechanics method.
2001 Vol. 17 (01): 165-166 [Abstract] ( 333 ) [HTML 1KB] [PDF 109KB] ( 443 )
167 Takayoshi Ohji, Yoko Tsuji, Fumikazu Miyasakn, Takeshi Yamamoto
Mathematical modeling of metal active gas (MAG) arc welding
In the present paper, a numerical model for MAG (metal active gas) are welding of thin plate has been developed. In MAG are welding, the electrode wire is melted and supplied into the molten pool intermittently. Accordingly, it is assumed on the modeling that the thermal energy enters the base-plates through two following mechanisms, i.e., direct heating from are plasma and "indirect" heating from the deposited metal. In the second part of the paper, MAG are welding process is numerically analyzed by using the model, and the calculated weld bead dimension and surface profile have been compared with the experimental MAG welds on steel plate. As the result, it is made clear that the model is capable of predicting the bead profile of thin-plate MAG are welding, including weld bead with undercutting.
2001 Vol. 17 (01): 167-168 [Abstract] ( 370 ) [HTML 1KB] [PDF 90KB] ( 547 )
169 Tie GANG, Xiaodong HAN Chunlong SHEN, Jin ZHAN
Background simulation and correction algorithm in spot weld image processing
One of the chief works for inspecting spot weld quality by X-ray to obtain an ideal and uniform digital image. This paper introduces three methods of image background simulation algorithm, and the effect of background correction was, compared. It may be safely said that Kalman filter method is simple and fast for general image, the FFT method has a good adaptability for background simulation.
2001 Vol. 17 (01): 169-170 [Abstract] ( 347 ) [HTML 1KB] [PDF 77KB] ( 372 )
171 Yongping LEI, Xianghua GU, Yaowu SHI
Numerical analysis of two-way interaction between weld-pool and arc for GTA welding process
A mathematical model to describe the heat transfer and fluid flow in the mutually coupled weld pool and are by an interactive free surface of the pool for a stationary gas tungsten are welding (GTAW) is developed. The two sets of governing equations and auxiliary formulas, controlling the weld pool and plasma are systems respectively, were solved by a finite difference method. A boundary-fitted coordinate system was adopted because the free surface has a curved and unknown shape during welding. The results of this work provide a fundamental basis for predicting the behavior of an integrated weld pool and are system from first principles.
2001 Vol. 17 (01): 171-172 [Abstract] ( 378 ) [HTML 1KB] [PDF 84KB] ( 335 )
173 Jitai NIU, Zhonghong LAI, MuZhen WANG, Liming LIU, Lin WU
Study on laser welding of Al composite
The effects of laser welding parameter on strength of welded joints were studied. The mechanism for loss of joint strength was analyzed. It was pointed out that an important factor affecting joint strength is the reaction between matrix and reinforced phase. On the basis of this, the concept of critical Si activity alpha ([si]min) was proposed. Using appropriate welding parameters and Si activity, high quality laser welded joints in an aluminum matrix composite SiCW/6061A1 can be successfully obtained.
2001 Vol. 17 (01): 173-174 [Abstract] ( 371 ) [HTML 1KB] [PDF 119KB] ( 357 )
175 Jiuba WEN, Yongshun YANG
Microstructure and properties of superplastic welding between 40Cr and CrWMn steels
Superplastic welding of tool steel and structural steel was investigated. The welding between 40Cr and CrWMn steels was carried out under the conditions of temperature 750 similar to 780 degreesC, strain rate 2x10(-4) s(-1), compressive stress 50 similar to 90 MPa for 3 similar to5 min. The joints show similar strength to that of 40Cr steel and the good metallurgical joining is formed. The structural change occurring during superplastic welding was analyzed by metallography and distribution of carbon content in the vicinity of the welding joint was also determined. The mechanism of superplastic welding for steels is proposed to be the disappearance of original bond interfaces caused by atomic diffusion and the grain sliding.
2001 Vol. 17 (01): 175-176 [Abstract] ( 360 ) [HTML 1KB] [PDF 111KB] ( 376 )
177 Yuxian LIU, Dongsheng SUN, Xiufang BIAN, Limei XIAO, Guili GENG, Yujun BAI
Defects in an as-quenched CuZnAlMnNi shape memory alloy
The defects in an as-quenched CuZnAlMnNi shape memory alloy were systemically observed by transmission electron microscopy. It was found that the dislocation loops in fine martensite plates generated during quenching extend along the direction of width or length, and form the stacking faults along certain angles with the plate boundaries or approximately parallel to the boundaries.
2001 Vol. 17 (01): 177- [Abstract] ( 354 ) [HTML 1KB] [PDF 665KB] ( 353 )
177 Yanhong WEI, Yingchun ZHANG, Renpei LIU, Zujie DONG
A computer aided system for stimulating weld metal solidification crack
A computer-aided system for simulating weld solidification crack has been developed by which a welding engineer can carry out the welding solidification crack simulation on the basis of a commercial finite element analysis software package. Its main functions include calculating the heat generations of the moving are, mesh generation, calculating stress-strain distributions with element rebirth technique.
2001 Vol. 17 (01): 177-178 [Abstract] ( 371 ) [HTML 1KB] [PDF 79KB] ( 387 )
179 Weiping LIU, Danping ZHU, Guozhi CONG
Combustion synthesis of NiAl and in-situ joining to Ni-based superalloy
Combustion synthesis is used as a joining technology to join Ni-based superalloys with in-situ synthesized NiAl filler. The synthesis mechanism is discussed. The microstructure of the joints is investigated and the joint strength is also evaluated by tensile testing.
2001 Vol. 17 (01): 179-180 [Abstract] ( 362 ) [HTML 1KB] [PDF 165KB] ( 322 )
180 Fuchi WANG, Zhaohui ZHANG, Shukui LI
Hydrodynamic analysis to process of hydrostatic extrusion for tungsten alloy
The hydrodynamic analysis to the process of the hydrostatic extrusion for tungsten alloy is carried through the hydrodynamic lubrication theory and Reynolds equation in this paper. The critical velocity equation when the hydrodynamic lubrication conditions appear between the surfaces of the work- piece and the die is obtained, and the relationship between the critical velocity and the extrusion parameters is discussed, which build the theoretical bases to the application of the hydrostatic extrusion for tungsten alloy.
2001 Vol. 17 (01): 180- [Abstract] ( 351 ) [HTML 1KB] [PDF 545KB] ( 423 )
181 Tong LIU, Jinsong TIAN, Lin WU, Ming DAI
Feature-based design of welded structure for robotic arc welding off-line programming
Feature modeler of welded structure provides both 3D-geographical and non-geographical features for the off-line programming of are welded robot. Welded structure is regarded as an assembly, the design of welded structure consists of three aspects: plane, joint, and groove design. Each aspect corresponds to a category of features. The plane features are defined by interactive feature definition. A method analogous to the "mating feature" is introduced to represent the joint features. Based on AutoCAD 2000, a B-rep solid modeler, a prototype system is implemented.
2001 Vol. 17 (01): 181-182 [Abstract] ( 364 ) [HTML 1KB] [PDF 68KB] ( 382 )
183 Zhihua LIU, Qing ZHAO, Deqing LI
Study of Hollow Cathode Arc Welding Technology for Ti Alloys
In this paper, technology margin experiment of hollow cathode fusion are welding (FAW) and penetrating are welding (PAW) is presented in detail. The advantages of PAW, compared with FAW, are better weld formation, narrower welds, as well as a larger welding technology margin. Technological experiment and hydraulic test for the Ti alloy pressure vessels with PAW are described. Also, the weld formation control on Ti alloys is preliminarily analyzed. Finally, conclusions are addressed.
2001 Vol. 17 (01): 183-184 [Abstract] ( 363 ) [HTML 1KB] [PDF 71KB] ( 398 )
185 Tao QIU, Shanben CHEN, Yuntao WANG, Lin WU
Modeling and control of welding flexible manufacturing cell using petri net
A new welding flexible manufacturing cell (WFMC) with intelligent welding sensors was investigated. Based on the analysis of information flow in WFMC, automation Petri net control model has been studied, which can be extended to complex welding flexible manufacturing system in the future.
2001 Vol. 17 (01): 185-186 [Abstract] ( 350 ) [HTML 1KB] [PDF 67KB] ( 450 )
187 Hongming GAO, Lin WU, Honggang DONG
Current density distribution in double-sided GTAW process
A three dimensional current density distribution in double-sided gas tungsten are welding (GTAW) proces is performed. The current density distribution field is evaluated by numerically solving Maxwell equations in the domain of the workpiece. In the boundary condition, the current density on the workpiece surface is assumed as Gaussian distribution. Results show that the current distribution in DSAW is different from single side are welding, it is more concentrated and the relative location of the two torches influence the current distribution greatly.
2001 Vol. 17 (01): 187-188 [Abstract] ( 336 ) [HTML 1KB] [PDF 84KB] ( 311 )
189 Keke ZHANG, Yunlin YANG, Changsheng WANG, Hongke LI, Jin XUE
Superplastic solid-phase welding of 40 Cr-T10A steel
The microstructure of 40Cr and T10A steel sample and its surface to be welded is ultra-fined through salt-bath cyclic quenching and high frequency hardening, then the surface is cleaned. Under non-vacuum and no shielded gas, the welding parameter of isothermal superplastic solid-phase welding and the effect of surface microstructure prior to pressure welding on the quality of joint are stud led. At the temperature of 730 similar to 750 ℃ and at initial strain rate of (2～4) x 10(-4) s(-1) the strength of the joint is up to or close to that of 40Cr base metal in 3 similar to5 min pressure welding.
2001 Vol. 17 (01): 189-190 [Abstract] ( 360 ) [HTML 1KB] [PDF 80KB] ( 375 )
191 Wenbo HAN, Jiuhai ZHANG
Diffusion bonding between TiAl based alloys and steels
The joint of 40Cr steel and TiAl based alloy has been studied by means of a high frequency induction diffusion welder. The experimental results show that, the higher the temperature and pressure, the higher the strength of the joints. The optimum parameters are: T=1123 similar to 1323 K, t=10 similar to 30 min, P=5 similar to 20 MPa.
2001 Vol. 17 (01): 191-192 [Abstract] ( 348 ) [HTML 1KB] [PDF 101KB] ( 377 )
193 Xin MA, Yiyu QIAN, Hongyuan FANG, F. Yoshida
Relative damage stress: Dominant mechanical factor for the failure of soldered joints under temperature cycling
By temperature normalization of the concept of equivalent damage stress proposed by Lemaitre, a new concept of relative damage stress has been put forward as the dominant mechanical factor for the failure of soldered joints under temperature cycling. Finite element numerical simulation results showed that the highest value of relative damage stress occurred at the high temperature hold time during temperature cycling history.
2001 Vol. 17 (01): 193-194 [Abstract] ( 351 ) [HTML 1KB] [PDF 59KB] ( 400 )
195 Jingquan LIU, Jiuchun YAN, Shiqin YANG
A preliminary study on ultrasonic cutting process for carbon fibre prepreg
In ultrasonic cutting process, the cutting pressure is still essential for achieving good quality cut edge compared with traditional mechanical cutting process. With the increase of the cutting power, the cutting pressure demand decreases. The cutting velocity range is extended broadly. The experiment results show that ultrasonic cutting, technique is an effective, clean and controllable method for machining of carbon fibre prepreg.
2001 Vol. 17 (01): 195-196 [Abstract] ( 348 ) [HTML 1KB] [PDF 63KB] ( 683 )

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