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ISSN 1005-0302
CN 21-1315/TG
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Current Issue
 20 July 2017, Volume 33 Issue 7 Previous Issue    Next Issue
Orginal Article
 Select Twin boundary: Controllable interface to fatigue cracking. Zhang Zhefeng, Li Linlin, Zhang Zhenjun, Zhang Peng J. Mater. Sci. Technol., 2017, 33 (7): 603-606.  DOI: 10.1016/j.jmst.2017.03.022 Twin boundaries (TBs) are key factors influencing the mechanical properties of crystalline materials. We have investigated the intrinsic fatigue cracking mechanisms of TBs during the past decade. The effects of TB orientations on the fatigue cracking mechanisms were revealed via cyclic deformation of a series of grown Cu bicrystals with a sole TB. Furthermore, the combined effects of crystallographic orientation and stacking fault energy (SFE) on the fatigue cracking mechanisms were clarified through cyclic deformation of polycrystalline Cu and Cu alloys. Both developments were reviewed in this report which will provide implications to optimize the interfacial design for the improvement of fatigue performance of metallic materials.
 Select Biological effect and molecular mechanism study of biomaterials based on proteomic research Zhen Zhen, Zheng Yufeng, Ge Zigang, Lai Chen, Xi Tingfei J. Mater. Sci. Technol., 2017, 33 (7): 607-615.  DOI: 10.1016/j.jmst.2017.01.001 Along with the role transformation of biomaterials from bioinert substitute to regenerative inducer, the biological effect and mechanism of material-organism interaction become more important. Since most of animal tests and cellular experiments stay on the phenomenon description instead of mechanism interpretation, the development of proteomics technologies provides a golden opportunity to uncover the molecular interaction mechanism between biomaterial-organism on whole scale. This review summarizes current application of proteomics in biological effect and mechanism study of biomaterials, and discusses the development and challenges for future studies.
 Select Influence of C/Ti stoichiometry in TiCx on the grain refinement efficiency of Al-Ti-C master alloy Yang Huabing, Gao Tong, Wang Haichao, Nie Jinfeng, Liu Xiangfa J. Mater. Sci. Technol., 2017, 33 (7): 616-622.  DOI: 10.1016/j.jmst.2017.04.015 TiCx contained Al-Ti-C is a kind of grain refiner for Al alloys. In this work, the influence of C/Ti stoichiometry, i.e. the x value in TiCx on grain refinement efficiency was investigated. TiCx particles have been obtained in five Al-5Ti-mC (m = 0.1, 0.5, 0.8, 1, 1.25) master alloys and the x values were measured to be 0.72, 0.75, 0.79, 0.81and 0.8, respectively. It was found that the refinement performance of the master alloys had a close relationship with the x value of TiCx. The Al-5Ti-mC alloy with lower-x TiCx shows better refinement efficiency and anti-fading capability. It is supposed that TiCx particles with lower x are more preferred to release Ti atoms during nucleating process and have a better Ti-absorbing capability. This contributes to the Ti-rich zone formation at TiCx/melt interface, thus enhancing the refinement and anti-fading capability.
 Select Semisolid-rolling and annealing process of woven carbon fibers reinforced Al-matrix composites Zhang Junjia, Liu Shichao, Lu Yiping, Jiang Li, Zhang Yubo, Li Tingju J. Mater. Sci. Technol., 2017, 33 (7): 623-629.  DOI: 10.1016/j.jmst.2017.01.002 Semisolid-rolling method was successfully developed to prepare the Ni-coated woven carbon fibers reinforced Al-matrix composite. Due to the appropriate matrix flowability and rolling pressure, the Al-matrix could infiltrate into the woven fibers sufficiently and attach to the reinforcements closely forming a smooth interface. The rolling speed of 4 rad/min offered a subtle equilibrium between the heat transfer and the material deformation. The covering matrix should be controlled at semisolid state to provide a better infiltration behavior and a protective effect on the carbon fibers. With the addition of fibers, an improvement for more than 25% was obtained in the bending strength of the materials. Furthermore, the woven carbon fibers could strengthen the composite in multiple directions, rather than only along the fiber longitudinal directions. The annealing process promoted the Ni coating to react with and to diffuse into the matrix, resulted in an obvious increase of the bending strength.
 Select Effect of rolling deformation on microstructure and texture of spray-deposited magnesium alloy containing Mg-Nd-Zn typed LPSO Li Zhenliang, Liu Fei, Yuan Aiping, Duan Baoyu, Li Yiming, Li Xiaowei J. Mater. Sci. Technol., 2017, 33 (7): 630-636.  DOI: 10.1016/j.jmst.2017.02.003 Billets of Mg-9Al-3Zn-1Mn-6Ca-2Nd alloy were produced by spray-deposition (the Osprey process). Effect of rolling deformation (T = 350 °C, ε = 5%, 10%, and 15%, respectively) on microstructure and texture evolution of the Mg-9Al-3Zn-1Mn-6Ca-2Nd alloy was investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Results show that at pass reduction of ε = 5%, 10% and 15% at 350 °C respectively, Mg-Nd-Zn typed 24R-LPSO structure was formed in (Ca, Nd)Al2 phase (C15 Laves phase). With the increase in pass reduction (i.e. 5%, 10% and 15%), the texture pole density level of basal texture (0002) changed little and pyramidal texture (10$1?$3) were increased. In contrast, those of prismatic texture {10$1?$0} <11$2?$0> were increased initially and followed by a reduction, indicating texture randomization in the grain-refined Mg alloy. The combined contribution of LPSO phase and C15 phase was key to randomize the texture of the grain-refined Mg alloy. It was noted that the microcosmic plastic deformation of LPSO phase and nanometer-sized dispersed C15 phase impeded dislocation movement, led to dislocation tangles, and facilitated recrystallization.
 Select Constitutive Relationship and Hot Processing Maps of Mg-Gd-Y-Nb-Zr Alloy Zhou Zhaohui, Fan Qichao, Xia Zhihui, Hao Aiguo, Yang Wenhua, Ji Wei, Cao Haiqiao J. Mater. Sci. Technol., 2017, 33 (7): 637-644.  DOI: 10.1016/j.jmst.2015.10.019 The hot working behavior of Mg-Gd-Y-Nb-Zr alloy was investigated using constitutive model and hot processing maps in this work. Isothermal compression tests were conducted with temperature and strain rate range of 703-773 K and 0.01-5 s-1, respectively. Improved Arrhenius-type equation incorporated with strain compensations was used to predict flow behavior of the alloy, and the predictability was evaluated using correlation coefficient, root mean square error and absolute relative error. Processing maps were constructed at different strains for Mg-Gd-Y-Nb-Zr alloy based on dynamic materials model. The processing maps are divided into three domains and the corresponding microstructure evolutions are referred to the forming of straight grain boundaries, twinning, dynamic recrystallization and grain growth. Instability occurred mainly at the strain rate range of 0.3s-1-0.5s-1. The optimum processing domain is mainly at the temperature range of 703-765 K with the strain rate range of 0.01-0.1 s-1.
 Select Effects of Load on Dry Sliding Wear Behavior of Mg-Gd-Zn-Zr Alloys Zhang Jie, Zhang Xiaobo, Liu Qinghua, Yang Shujie, Wang Zhangzhong J. Mater. Sci. Technol., 2017, 33 (7): 645-651.  DOI: 10.1016/j.jmst.2016.11.014 Dry sliding wear tests on as-cast and T6-treated Mg-3Gd-1Zn-0.4Zr (wt%, GZ31K) and Mg-6Gd-1Zn-0.4Zr (wt%, GZ61K) alloys were performed using a ball-on-disk configuration at room temperature. Friction coefficient and wear rate of the alloys were measured under three different applied loads (50 N, 100 N, and 200 N, respectively). Worn surface morphologies were analyzed using a scanning electron microscope (SEM) coupled with an energy dispersive spectrometer (EDS). It is found that the friction coefficient of the alloys decreases with increasing load, except the as-cast GZ61K. The wear rates of the as-cast Mg-Gd-Zn-Zr alloys increase with the increase of the load. However, the wear rates of the T6-treated Mg-Gd-Zn-Zr alloys first increase because of the participation of a large amount of needle-like precipitates, but then decline due to obvious work hardening. The wear mechanisms of abrasion, plastic deformation, oxidation, adhesion and delamination are detected. Abrasion dominates the wear mechanism under the low load; whereas, adhesion is the main wear mechanism under intermediate load, and plastic deformation has great effect on the wear rate under high applied load.
 Select Superior Properties of Mg-4Y-3RE-Zr Alloy Prepared by Powder Metallurgy Kubásek Ji?í, Dvorsky Drahomír, ?avojsky Miroslav, Vojtěch Dalibor, Beronská Nad'a, Fousová Michaela J. Mater. Sci. Technol., 2017, 33 (7): 652-660.  DOI: 10.1016/j.jmst.2016.09.019 Magnesium alloys are important materials for application in the automotive and aviation industries. During the last few years, the number of possible applications as biodegradable implants in medicine has grown. Mg-RE (rare earth) alloys belong to the most advanced group of products, offering the best combination of mechanical properties and corrosion resistance. Among these materials, WE43 (Mg-Y-Nd) is a very well-known commercial alloy that has been extensively studied for applications at increased temperatures and also in organisms. Although this material has been described, there are still possibilities to improve its properties and subsequently expand its applicability. Powder metallurgy has already been used for the preparation of magnesium alloys with superior mechanical properties and occasionally superior corrosion properties. Therefore, the present paper is oriented toward the preparation of Mg-4Y-3RE-Zr (WE43) alloy by the powder metallurgy technique (WE43-PM) and comparison of the final properties with the product of extrusion of as-cast ingot (WE43-IM). Our processing leads to a partial improvement in the mechanical properties and superior corrosion resistance of WE43-PM. The texture strength of WE43-PM was low, and therefore, anisotropy of mechanical properties was suppressed.
 Select Protective Composite Coatings Formed on Mg Alloy Surface by PEO Using Organofluorine Materials V. Mashtalyar Dmitry, V. Nadaraia Konstantine, L. Sinebryukhov Sergey, V. Gnedenkov Sergey J. Mater. Sci. Technol., 2017, 33 (7): 661-667.  DOI: 10.1016/j.jmst.2016.09.006 The results of the surface modification of magnesium alloys by plasma electrolytic oxidation (PEO) and subsequent treatment in suspension of the superdispersed polytetrafluoroethylene (SPTFE) or telomeric solution of tetrafluoroethylene (TFE) are presented. Composite coatings have been obtained by dipping with subsequent heat treatment. Electrochemical, tribological properties and wettability of protective composite coatings have been investigated. Composite coatings formed on PEO-layer by fourfold treatment of samples in SPTFE suspension possess best protective properties. The obtained coatings decrease the corrosion current density (5.4 × 10-11 A cm-2) and wear (7.6 × 10-7 mm3 (N m)-1), and increase the polarisation resistance (1.7 × 109 Ω cm2) and impedance modulus (1.9 × 109 Ω cm2) by orders of magnitude in comparison with unprotected magnesium alloy and base PEO-coating. The highest value of contact angle (CA) has been obtained for coatings with triple application in telomeric solution. CA for such composite coatings attains (171 ± 2)°, as the result of multimodal roughness of the composite coating's surface.
 Select Mechanical Properties and Fracture Behavior of Mg-Al/AlN Composites with Different Particle Contents Chen Jie, Bao Chonggao, Chen Wenhui, Zhang Li, Liu Jinling J. Mater. Sci. Technol., 2017, 33 (7): 668-674.  DOI: 10.1016/j.jmst.2016.07.010 In this study, magnesium matrix composites reinforced with different loading of AlN particles were fabricated by the powder metallurgy technique. The microstructure, bending strength and fracture behavior of the resulting Mg-Al/AlN composites were investigated. It showed that the 5 wt% AlN reinforcements led to the highest densification and bending strength. The total strengthening effect of AlN particles was predicted by considering the contributions of CTE mismatch between the matrix and the particles, load bearing and Hall-Petch mechanism. The results revealed that the increase of dislocation density, the change of Mg17Al12 phase morphology, and the effective load transfer were the major strengthening contributors to the composites. The fracture of the composites altered from plastic to brittle mode with increasing reinforcement content. The regions of clustered particles in the composites were easy to be damaged under external load, and the fracture occurred mainly along grain boundaries.
 Select Influence of α/β interface phase on the tensile properties of laser cladding deposited Ti-6Al-4V titanium alloy Zhao Zhuang, Chen Jing, Guo Shuai, Tan Hua, Lin Xin, Huang Weidong J. Mater. Sci. Technol., 2017, 33 (7): 675-681.  DOI: 10.1016/j.jmst.2016.09.026 Laser cladding deposited Ti-6Al-4V titanium alloy universally shows more complex microstructures, each of which has significant effect on mechanical properties. Of particular α/β interface phase has been observed in this paper under certain conditions. It demonstrates that the influence of the α/β interface phase on the tensile properties is closely associated with dislocations and twin substructure through comparison experiments. The results show that the α/β interface phase hinders dislocation motion and decreases effective slip length. In addition, the twin substructure has been activated in the α/β interface phase during tensile process and has acted somehow like grain boundaries. Therefore, the strength and the work-hardening rate of the laser cladding deposited Ti-6Al-4V titanium alloy have been significantly improved due to the dynamic Hall-Petch effect. Besides, the α/β interface phase leads to more uniform dislocations distribution, which implies that relative lower local concentrated stress will be produced along the α/β interface phase or colony boundary after the same amount of plastic deformation. Moreover, the twinning-induced plasticity effects in the α/β interface phase further increase the plastic deformation capacity. These results in higher elongation for the laser cladding deposited Ti-6Al-4V titanium alloy. It can be concluded that the current work suggests an effective method to simultaneously improve the strength and plasticity of laser cladding deposited Ti-6Al-4V titanium alloy based on the α/β interface phase.
 Select Effects of Nb content in Ti-Ni-Nb brazing alloys on the microstructure and mechanical properties of Ti-22Al-25Nb alloy brazed joints Wang Y., Cai X.Q., Yang Z.W., Wang D.P., Liu X.G., Liu Y.C. J. Mater. Sci. Technol., 2017, 33 (7): 682-689.  DOI: 10.1016/j.jmst.2017.03.021 Vacuum brazing was successfully used to join Ti-22Al-25Nb alloy using Ti-Ni-Nb brazing alloys prepared by arc-melting. The influence of Nb content in the Ti-Ni-Nb brazing alloys on the interfacial microstructure and mechanical properties of the brazed joints was investigated. The results showed that the interfacial microstructure of brazed joint consisted of B2, O, τ3, and Ti2Ni phase, while the width of brazing seams varied at different Nb contents. The room temperature shear strength reached 359 MPa when the joints were brazed with eutectic Ti40Ni40Nb20 alloy at 1180 °C for 20 min, and it was 321, 308 and 256 MPa at 500, 650 and 800 °C, respectively. Cracks primarily initiated and propagated in τ3 compounds, and partially traversed B2+O region. Moreover, the fracture surface displayed typical ductile dimples when cracks propagated through B2+O region, which was favorable for the mechanical properties of the brazed joint.
 Select Evolution of microstructure and texture in copper during repetitive extrusion-upsetting and subsequent annealing Chen Q., Shu D.Y., Lin J., Wu Y., Xia X.S., Huang S.H., Zhao Z.D., Mishin O.V., Wu G.L. J. Mater. Sci. Technol., 2017, 33 (7): 690-697.  DOI: 10.1016/j.jmst.2017.03.003 The evolution of the microstructure and texture in copper has been studied during repetitive extrusion-upsetting (REU) to a total von Mises strain of 4.7 and during subsequent annealing at different temperatures. It is found that the texture is significantly altered by each deformation pass. A duplex 〈001〉 + 〈111〉 fiber texture with an increased 〈111〉 component is observed after each extrusion pass, whereas the 〈110〉 fiber component dominates the texture after each upsetting pass. During REU, the microstructure is refined by deformation-induced boundaries. The average cell size after a total strain of 4.7 is measured to be ~0.3 μm. This refined microstructure is unstable at room temperature as is evident from the presence of a small number of recrystallized grains in the deformed matrix. Pronounced recrystallization took place during annealing at 200 °C for 1 h with recrystallized grains developing predominantly in high misorientation regions. At 350 °C the microstructure is fully recrystallized with an average grain size of only 2.3 μm and a very weak crystallographic texture. This REU-processed and subsequently annealed material is considered to be potentially suitable for using as a material for sputtering targets.
 Select Deformation behaviors of Cu bicrystals with an inclined twin boundary at multiple scales Li L.L., Zhang Z.J., Zhang P., Tan J., Yang J.B., Zhang Z.F. J. Mater. Sci. Technol., 2017, 33 (7): 698-702.  DOI: 10.1016/j.jmst.2016.11.030 Cu bicrystals of different sizes with a sole twin boundary (TB) inclined at 45° with respect to the loading direction were deformed under unidirectional and cyclic loading, respectively. It is found that the slip bands (SBs) parallel to the TB can be activated near the TB at all scales without obeying the Schmid’s law. It is concerned with the local stress enhancement in the macroscale while it is more closely related to the scarce dislocation sources in the microscale. Moreover, a wedge-shaped zone formed near the TB in the microscale ascribed to the limited specimen size.
 Select Micro injection of metallic glasses parts under ultrasonic vibration Liang X., Ma J., Wu X.Y., Xu B., Gong F., Lei J.G., Peng T.J., Cheng R. J. Mater. Sci. Technol., 2017, 33 (7): 703-707.  DOI: 10.1016/j.jmst.2016.10.012 This work investigates the evolution of structure and mechanical performance of metallic glasses (MGs) under a proposed rapid forming approach. Through the unique ultrasonic-assisted micro injection method, micro MGs parts with fine dimensional accuracy were successfully fabricated. The temperature during the micro injection is higher than the glass transition temperature and lower than the crystallization temperature. Differential scanning calorimeter curve and X-ray diffraction pattern show that the MGs micro parts keep the amorphous nature after the ultrasonic-assisted micro injection. Our results propose a novel route for the fast forming of MGs and have promising applications in the rapid fabrication of micro scale products and devices.
 Select Distribution of Be in a Ti-Based Bulk Metallic Glass Composite Containing B-Ti Zhang L., Li W.Q., Zhu Z.W., Fu H.M., Li H., Li Z.K., Zhang H.W., Wang A.M., Zhang H.F. J. Mater. Sci. Technol., 2017, 33 (7): 708-711.  DOI: 10.1016/j.jmst.2016.03.025 In order to obtain a glassy matrix during quenching, Be is often selected as a constituent of the compositions of Ti/Zr-based bulk metallic glass composites (BMGCs). The in situ formed β phase in Be-bearing BMGCs was reported to be Be-free. However, a thorough investigation of the distribution of Be in BMGCs is still missing to date. In this work, the distribution of Be in a Ti47.5Zr33Cu5.8Co3Be12.5 (at.%) BMGC was studied by the secondary ion mass spectrometry (SIMS) and the electron energy loss spectroscopy (EELS). It is found that Be almost totally dissolves in the glassy matrix, but a very weak intensity of Be in β phase is still detectable by SIMS, and the content of Be in β-Ti is estimated to be about 0.3 at.%. Based on the recently established two-phase quasi-equilibrium of BMGCs, the distinct solubility of Be in the glassy matrix and in β-Ti has been explained.
 Select Effect of Niobium on Microstructure and Properties of the CoCrFeNbxNi High Entropy Alloys Jiang Hui, Jiang Li, Qiao Dongxu, Lu Yiping, Wang Tongmin, Cao Zhiqiang, Li Tingju J. Mater. Sci. Technol., 2017, 33 (7): 712-717.  DOI: 10.1016/j.jmst.2016.09.016 A series of CoCrFeNbxNi (x values in molar ratio, x = 0, 0.25, 0.45, 0.5, 0.75, 1.0 and 1.2) high entropy alloys (HEAs) was prepared to investigate the alloying effect of Nb on the microstructures and mechanical properties. The results indicate that the prepared CoCrFeNbxNi (x > 0) HEAs consist of a simple FCC solid solution phase and a Laves phase. The microstructures of the alloys change from an initial single-phase FCC solid solution structure (x = 0) to a hypoeutectic microstructure (x = 0.25), then to a full eutectic microstructure (x = 0.45) and finally to a hypereutectic microstructure (0.5 < x < 1.2). The compressive test results show that the Nb0.45 (x = 0.45) alloy with a full eutectic microstructure possesses the highest compressive fracture strength of 2558 MPa and a fracture strain of 27.9%. The CoCrFeNi alloy exhibits an excellent compressive ductility, which can reach 50% height reduction without fracture. The Nb0.25 alloy with a hypoeutectic structure exhibits a larger plastic strain of 34.8%. With the increase of Nb content, increased hard/brittle Laves phase leads to a decrease of the plasticity and increases of the Vickers hardness and the wear resistance. The wear mass loss, width and depth of wear scar of the Nb1.2 (x = 1.2) alloy with a hypereutectic structure are the lowest among all alloy systems, indicating that the wear resistance of the Nb1.2 alloy is the best one.
 Select Deformation Strength of Nanocrystalline Thin Films Blum W., Eisenlohr P. J. Mater. Sci. Technol., 2017, 33 (7): 718-722.  DOI: 10.1016/j.jmst.2016.11.025 The data of deformation strength and microstructure of thin films of nanocrystalline Pd recently provided by Colla et al. have been analysed. It is shown that the properties of the films with cylindrical grains of 30 nm diameter extending over a significant portion of the film thickness (≈90 nm) are quantitatively comparable to what is known from nanocrystalline bulk material. This is explained in terms of boundary-mediated processes governing emission, storage, and recovery of dislocations.
 Select Effect of Cu Addition to 2205 Duplex Stainless Steel on the Resistance against Pitting Corrosion by the Pseudomonas aeruginosa Biofilm Li Ping, Zhao Yang, Liu Yuzhi, Zhao Ying, Xu Dake, Yang Chunguang, Zhang Tao, Gu Tingyue, Yang Ke J. Mater. Sci. Technol., 2017, 33 (7): 723-733.  DOI: 10.1016/j.jmst.2016.11.020 The effect of copper addition to 2205 duplex stainless steel (DSS) on its resistance against pitting corrosion by the Pseudomonas aeruginosa biofilm was investigated using electrochemical and surface analysis techniques. Cu addition decreased the general corrosion resistance, resulting in a higher general corrosion rate in the sterile medium. Because DSS usually has a very small general corrosion rate, its pitting corrosion resistance is far more important. In this work, it was shown that 2205-3%Cu DSS exhibited a much higher pitting corrosion resistance against the P. aeruginosa biofilm compared with the 2205 DSS control, characterized by no significant change in the pitting potential and critical pitting temperature (CPT) values. The strong pitting resistance ability of 2205-3%Cu DSS could be attributed to the copper-rich phases on the surface and the release of copper ions, providing a strong antibacterial ability that inhibited the attachment and growth of the corrosive P. aeruginosa biofilm.
 Select Inorganic Nanotube/Organic Nanoparticle Hybrids for Chen Yingzhi, Li Aoxiang, Jin Ming, Lu-NingWang, Zheng-HongHuang J. Mater. Sci. Technol., 2017, 33 (7): 728-733.  DOI: 10.1016/j.jmst.2016.08.030 Inorganic/organic nanohybrids composed of arrayed TiO2 nanotubes (TiNTs)/porphyrin nanoparticles (NPs) have been fabricated via a wet chemical approach. The inorganic component, particularly the arrayed one-dimensional (1D) nanostructures, provides high charge-carrier mobility and rapid charge transport. The organic component exhibits extensive visible light absorption and good solution processability. Additionally, the geometric restraint by supramolecular assembly renders an improved photostability. A combination of these two components could thus allow for an efficient solar energy conversion. In this work, a colloid of porphyrin NPs prepared by a solvent exchange method is coated on anodic TiNTs by means of a dip-coating treatment to form inorganic/organic hybrids. The hybrids exhibit an improvement on solar absorption and a significant enhancement on photocurrent generation at a small bias compared with individual component. Herein, the inorganic/organic nanohybrids are proved to be excellent photoanodes highly responsive to visible light and thus pave a way to discover new inorganic/organic assemblies for high-performance optoelectronic applications, as well as for device integration.
 Select Effect of Porous Activated Charcoal Reinforcement on Mechanical and In-Vitro Biological Properties of Polyvinyl Alcohol Composite Scaffolds Kaur Tejinder, Thirugnanam Arunachalam J. Mater. Sci. Technol., 2017, 33 (7): 734-743.  DOI: 10.1016/j.jmst.2016.06.020 The present work focused on developing an innovative composite material by reinforcing polymer matrix with highly porous activated charcoal. Polyvinyl alcohol-activated charcoal (PVA-AC) composite scaffolds were developed by varying the AC concentrations (0, 0.5, 1, 1.5, 2 and 2.5 wt%) in PVA matrix by freeze drying method. The developed scaffolds were characterized for their physicochemical, mechanical and in-vitro biological properties. In addition, the effect of AC on the attachment, proliferation and differentiation of osteoblast MG 63 cells was evaluated by scanning electron microscopy (SEM), 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, alkaline phosphatase (ALP) activity assay and alizarin red stain-based (ARS) assay. All the PVA-AC composite scaffolds exhibited good bioactivity, hemocompatibility and protein adsorption properties. The scaffolds with high AC concentration (2.5 wt%) showed controlled drug release kinetics that are suitable for long term healing. The mechanical properties of all the PVA-AC composite scaffolds were improved when compared to the pure PVA scaffold. The high porosity, swelling degree and hydrophilicity of PVA-AC composite scaffolds facilitated cell attachment and proliferation. This is due to porous AC present in the sample that supported the osteoblast differentiation and formed mineralized nodules without the addition of any extra agents. From the above studies, it can be concluded that PVA-AC composite scaffolds are promising biomaterials for bone tissue engineering applications.
 Select Magnetic/Magnetostrictive Properties Together with Resistivity and Corrosion Behaviors of CoFe2 and Its Composite with CoFe2N Geng B.Q., Ma Y.Q., Wang M., Ding Z.L., Song W.H., Zhao B.C. J. Mater. Sci. Technol., 2017, 33 (7): 744-750.  DOI: 10.1016/j.jmst.2016.07.006 The CoFe2 alloy (CF) was prepared by reducing CoFe2O4 in the H2 ambient. Subsequently the CF sample was nitrided in the NH3 atmosphere to produce the composite of CoFe2N and CoFe2. The magnetostriction, thermal expansion, resistivity and corrosion resistance of CF sample and the nitrided sample (CFN) at 1000 °C were investigated. The saturation magnetostriction coefficiency λs and thermal expansion coefficient α at 300 K for the nitrided CFN were 50 ppm and 10 ppm/K, respectively, approximately equal to those for the CF sample. However, compared with CF, CFN presents a decrease in temperature coefficient Rλ (300 K) of magnetostriction by ~11%. The smaller resistivity and improved corrosion resistance in the H2SO4 solution may expand the applications of the CoFe2 in the fields needing lower resistivity or in the acidic environment.
 Select Formation, Structures and Electronic Properties of Silicene Oxides on Ag(111) Ali Muhammad, Ni Zhenyi, Cottenier Stefaan, Liu Yong, Pi Xiaodong, Yang Deren J. Mater. Sci. Technol., 2017, 33 (7): 751-757.  DOI: 10.1016/j.jmst.2016.08.020 The formation, structural and electronic properties of silicene oxides (SOs) that result from the oxidation of silicene on Ag(111) surface have been investigated in the framework of density functional theory (DFT). It is found that the honeycomb lattice of silicene on the Ag(111) surface changes after the oxidation. SOs are strongly hybridized with the Ag(111) surface so that they possess metallic band structures. Charge accumulation between SOs and the Ag(111) surface indicates strong chemical bonding, which dramatically affects the electronic properties of SOs. When SOs are peeled off the Ag(111) surface, however, they may become semiconductors.
 Select Gradient Structured Copper by Rotationally Accelerated Shot Peening Wang X., Li Y.S., Zhang Q., Zhao Y.H., Zhu Y.T. J. Mater. Sci. Technol., 2017, 33 (7): 758-761.  DOI: 10.1016/j.jmst.2016.11.006 A new technology—rotationally accelerated shot peening (RASP), was developed to prepare gradient structured materials. By using centrifugal acceleration principle and large steel balls, the RASP technology can produce much higher impact energy compared to conventional shot peening. As a proof-of-concept demonstration, the RASP was utilized to refine the surface layer in pure copper (Cu) with an average grain size of ~85 nm. The grain size increases largely from surface downwards the bulk, forming an 800 μm thick gradient-structured surface layer and consequently a micro-hardness gradient. The difference between the RASP technology and other established techniques in preparing gradient structured materials is discussed. The RASP technology exhibits a promoting future for large-scale manufacturing of gradient materials.
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