Started in 1985 Semimonthly
ISSN 1005-0302
CN 21-1315/TG
Impact factor:6.155

The journal has been awarded the excellent periodical in China, and its articles are covered by SCI, EI, CA, SA, JST, RJ, CSA, MA, EMA, AIA etc., PASCAL web. ISI web of Science,SCOPUS.

  Current Issue
      15 August 2020, Volume 51 Issue 0 Previous Issue    Next Issue
    For Selected: View Abstracts Toggle Thumbnails
    Research Article
    Synthesis and photocatalytic performance of ZnO with flower-like structure from zinc oxide ore
    Xiaoyi Shen, Hongmei Shao, Yan Liu, Yuchun Zhai
    J. Mater. Sci. Technol., 2020, 51 (0): 1-7.  DOI: 10.1016/j.jmst.2020.01.062
    Abstract   HTML   PDF

    AAAAAEmploying zinc sulfate solution obtained from zinc oxide ore as raw material, sodium hydroxide as precipitant and PEG20000 as dispersant, ultrafine ZnO powders with different morphologies were successfully synthesized through hydrothermal method. The influences of the dosage of PEG20000 solution, molar ratio of OH -/Zn 2+, reaction temperature, reaction time and Zn 2+ concentration on the structures and morphologies of the ZnO powders were discussed in detail. The reaction conditions of synthesizing ZnO powders with flower-like structure were obtained as below: dosage of PEG20000 with 10% mass fraction 5 mL, molar ratio of OH - to Zn 2+ 5, reaction temperature 150 °C, reaction time 8 h at Zn 2+ concentration 1 mol L -1. The growth mechanism of ZnO particles with different morphologies was proposed. The ZnO powder with flower-like structure are composed of multiple micro-rods with hexagon morphology and has good photocatalytic degradation ability to degrade RhB. 20 mL RhB solution with 15 mg L -1 could be completely degraded over flower-like ZnO powder 300 mg within 3 h.

    Figures and Tables | References | Related Articles | Metrics
    Zwitterionic glycine modified Fe/Mg-layered double hydroxides for highly selective and efficient removal of oxyanions from polluted water
    Xiaofeng Shi, Chao Wang, Jiaoxia Zhang, Li Guo, Jing Lin, Duo Pan, Juying Zhou, Jincheng Fan, Tao Ding, Zhanhu Guo
    J. Mater. Sci. Technol., 2020, 51 (0): 8-15.  DOI: 10.1016/j.jmst.2019.12.034
    Abstract   HTML   PDF

    Zwitterionic glycine was employed to modify Fe/Mg-layered double hydroxides (LDH) to realize an G-Fe/Mg-LDH adsorbent with high adsorption capacities of oxygen-containing anions including As(V), P(V) and Cr(VI). When the Fe/Mg mole ratio was 0.02 mol/0.02 mol, the G-Fe/Mg-LDH has a good adsorption performance. The optimum adsorption pH value of G-Fe/Mg-LDH for oxygen-containing anions was 6. The selectivity of three oxygen-containing anions was Cr(VI)<P(V)<As(V), and the maximum adsorption capacity of As(V) reached as high as 830 mg g -1, outperforming most previously reported efficient adsorbents for As(V). The adsorption process followed Freundlich isotherm and pseudo-second-order kinetic model, suggesting the heterogeneous adsorption and chemical adsorption of the G-Fe/Mg-LDH. When the initial concentration of As(V) was 200 mg L -1, the adsorption efficiency of G-Fe/Mg-LDH was 82.5% within 30 min. This study provides a way to modify the LDHs for environmental remediation.

    Figures and Tables | References | Related Articles | Metrics
    Invited Review
    Portevin-Le Châtelier effect in wrought Ni-based superalloys: Experiments and mechanisms
    Chuanyong Cui, Rui Zhang, Yizhou Zhou, Xiaofeng Sun
    J. Mater. Sci. Technol., 2020, 51 (0): 16-31.  DOI: 10.1016/j.jmst.2020.03.023
    Abstract   HTML   PDF

    The Portevin-Le Chatelier (PLC) effect is a plastic instability in alloys at certain strain rates and deformation temperatures. This plastic instability exhibits serrated yielding in the temporal domain and strain localization in the spatial domain. Wrought Ni-based superalloys often exhibit the PLC effect. To guarantee the safe and stable operation of equipment, it is important to study the PLC effect in wrought Ni-based superalloys. This paper provides a review of various experimental phenomena and micromechanisms related to the PLC effect in wrought Ni-based superalloys, which have been reported in various publications in recent years and include work from our own group. The influences of stacking fault energy and γ′ precipitates on the PLC effect in wrought Ni-based superalloys are also discussed in detail. Additionally, several suggestions for the future study of the PLC effect in wrought Ni-based superalloys are provided.

    Figures and Tables | References | Related Articles | Metrics
    Research Article
    Synthesis of yttrium iron garnet/bismuth quantum dot heterostructures with localized plasmon enhanced magneto-optical performance
    Lichuan Jin, Caiyun Hong, Dainan Zhang, Peng Gao, Yiheng Rao, Gang Wang, Qinghui Yang, Zhiyong Zhong, Huaiwu Zhang
    J. Mater. Sci. Technol., 2020, 51 (0): 32-39.  DOI: 10.1016/j.jmst.2020.03.025
    Abstract   HTML   PDF

    Interactions between light and magnetic matter attracted great attention lately due to their potential applications in nanophotonics, spintronics, and high-accuracy sensing. Here, we grew bismuth quantum dots (Bi-QDs) with strong spin-orbit coupling on a magnetic insulator yttrium iron garnet (YIG) via molecular beam epitaxy. The YIG/Bi-QDs material shows an enhanced magneto-optical Kerr rotation up to 130% compared with that of a bare YIG film. The Bi-QDs were also introduced onto a lutetium-bismuth co-doped YIG film to form a hybrid system with remarkably enhanced Kerr rotation (from 1626 to 2341 mdeg). Ferromagnetic resonance measurements showed an increased effective magnetization as well as interfacial spin-orbit field in the YIG/Bi-QD heterostructures. Localized plasmons were mapped using electron energy loss spectroscopy with high spatial resolution, revealing enhanced plasmon intensity at both the Bi-QD surface and YIG/Bi-QD interface. Introducing Bi-QDs onto the YIG film enhanced Kerr rotation owing to the attenuated optical reflection and increased effective magnetization. The Bi-QD-enhanced magneto-optical effect enables development of efficient nanoscale light switching, spintronics, and even plasmonic nano-antennas.

    Figures and Tables | References | Related Articles | Metrics
    Microstructure induced galvanic corrosion evolution of SAC305 solder alloys in simulated marine atmosphere
    Mingna Wang, Chuang Qiao, Xiaolin Jiang, Long Hao, Xiahe Liu
    J. Mater. Sci. Technol., 2020, 51 (0): 40-53.  DOI: 10.1016/j.jmst.2020.03.024
    Abstract   HTML   PDF

    Motivated by the increasing use of Sn-3.0Ag-0.5Cu (SAC305) solder in electronics worked in marine atmospheric environment and the uneven distribution of Ag3Sn and Cu6Sn5 intermetallic compounds (IMCs) in β-Sn matrix, comb-like electrodes have been designed for in-situ EIS measurements to study the microstructure induced galvanic corrosion evolution of SAC305 solder in simulated marine atmosphere with high-temperature and high-humidity. Results indicate that in-situ EIS measurement by comb-like electrodes is an effective method for corrosion evolution behavior study of SAC305 solder. Besides, the galvanic effect between Ag3Sn IMCs and β-Sn matrix can aggravate the corrosion of both as-received and furnace-cooled SAC305 solder as the exposure time proceeds in spite of the presence of corrosion product layer. Pitting corrosion can be preferentially found on furnace-cooled SAC305 with larger Ag3Sn grain size. Moreover, the generated inner stress during phases transformation process with Sn3O(OH)2Cl2 as an intermediate and the possible hydrogen evolution at local acidified sites are supposed to be responsible for the loose, porous, cracked, and non-adherent corrosion product layer. These findings clearly demonstrate the corrosion acceleration behavior and mechanism of SAC305 solder, and provide potential guidelines on maintenance of microelectronic devices for safe operation and longer in-service duration.

    Figures and Tables | References | Related Articles | Metrics
    The characterization of Fe-rich phases in a high-pressure die cast hypoeutectic aluminum-silicon alloy
    X.Y. Jiao, C.F. Liu, Z.P. Guo, G.D. Tong, S.L. Ma, Y. Bi, Y.F. Zhang, S.M. Xiong
    J. Mater. Sci. Technol., 2020, 51 (0): 54-62.  DOI: 10.1016/j.jmst.2020.02.040
    Abstract   HTML   PDF

    Both microstructural characteristics and fracture behavior of Fe-rich phases in a high-pressure die-cast hypoeutectic Al-Si alloy were investigated. Attention was focused on the morphology and formation mechanism of Fe-rich phases, together with their influence on fracture. Results show that primary Fe-rich phases exhibited in blocky shape precipitated from liquid while secondary Fe-rich phase in a large net shape was distributed along eutectic boundary participating in a ternary eutectic reaction. Through synchrotron X-ray tomography characterization, three Fe-rich phases with different morphologies, i.e., polyhedral shape, fine compact shape and Chinese script-type shape were extracted along the radial direction. Lower slow-shot speed promoted the polyhedral Fe-rich phase to precipitate in slow-shot sleeve while decreased the formation of fine compact and Chinese script-type Fe-rich phases in die cavity. Because of a worse deformation compatibility, polyhedral Fe-rich phases fractured and became stress concentration sources before the failure of the casting.

    Figures and Tables | References | Related Articles | Metrics
    Role of competing interactions on dynamic relaxation and exchange bias in spin-glass/ferromagnet bilayer
    Xiaodan Chi, Yong Hu
    J. Mater. Sci. Technol., 2020, 51 (0): 63-69.  DOI: 10.1016/j.jmst.2020.02.043
    Abstract   HTML   PDF

    When a ferromagnet (FM) couples to a spin glass (SG), the hidden nature of SG may imprint on the FM via their interfacial coupling, probably resulting in elongated magnetic relaxation and enhanced unidirectional and uniaxial anisotropies. In parallel with the study of interfacial roles, e.g. interfacial coupling and matching, we focused on the influence of the competing interactions in SG (JSG) on the magnetic relaxation properties of SG/FM bilayer and the FM magnetization reversal involving exchange bias field (HE) and coercivity (HC). A fastest decay of relaxation in SG/FM bilayer is found at an intermediate JSG~5.2 erg/cm 2 and the relaxation parameters related to JSG are nonmonotonic. On the other hand, a pronounced HE of ~-0.26 kOe is observed at small JSG, and as JSG increases larger than 2.275 erg/cm 2, HE decreases by an order of magnitude and levels off, i.e., a net EB remains. HC is sensitive to JSG only at JSG above 2.275 erg/cm 2 and exhibits a minimum value at JSG = 4.55 erg/cm 2, just below 5.2 erg/cm 2 where the relaxation decay is the fastest. Microscopic analysis unravels that the net magnetization associated with unidirectional magnetic stabilization and the large-area FM-like domains in SG are favored at small JSG, while with increasing JSG, the SG spins spontaneously reverse and thus the energy barriers are smeared out. A high susceptibility and a strong interfacial coupling lead to FM magnetization reversal under weaker fields and thus a decrease in coercivity. For too large JSG (exceeding 5.2 erg/cm 2), magnetic frustration extends over the domains in SG meanwhile fierce energy competition occurs frequently, resembling enhanced quantum fluctuations. As a result, dynamic relaxation and statistic coercivity are both recovered. This work tells us that the independent modulations of unidirectional and uniaxial anisotropies are possible in SG-based systems through precisely controlling JSG, which is desired for application in the read/write head in future data storage media.

    Figures and Tables | References | Related Articles | Metrics
    Ti2AlC triggered in-situ ultrafine TiC/Inconel 718 composites: Microstructure and enhanced properties
    Wenqiang Hu, Zhenying Huang, Qun Yu, Yuanbo Wang, Yidan Jiao, Cong Lei, Leping Cai, Hongxiang Zhai, Yang Zhou
    J. Mater. Sci. Technol., 2020, 51 (0): 70-78.  DOI: 10.1016/j.jmst.2020.04.002
    Abstract   HTML   PDF

    In situ ultrafine TiC dispersion reinforced Inconel 718 alloy with enhanced mechanical properties was fabricated by the technique of reactive hot-press sintering Ti2AlC and In718 powders. The effect of Ti2AlC precursor additions (5 vol.%, 10 vol.%, 15 vol.%) on microstructure and mechanical properties of TiC/In718 composites were investigated. A relationship of microstructural characteristics, room and elevated temperature mechanical performance, and underlying strengthening mechanisms were analyzed. The results show that initial Ti2AlC precursor transformed completely into ultrafine TiC particulate (~230 nm) and distributed uniformly in the matrix after sintering 5 and 10 vol.% Ti2AlC/In718. However, TiC particulates tended to aggregate to stripes with the addition of Ti2AlC up to 15 vol.%, which, in adverse, weaken the properties of In718. The 5 vol.% Ti2AlC/In718 sample showed a higher tensile strength of 1404 ± 13 MPa with a noticeable elongation of 9.8% at room temperature compared to the pure In718 (ultimate tensile strength (UTS) = 1310 MPa, elongation = 21.5%). At 600 °C, 700 °C, 800 °C and 900 °C, tensile strength of the as-sintered 5 vol.% Ti2AlC/In718 composite was determined to be 1333 ± 13 MPa, 1010 ± 10 MPa, 685 ± 25 MPa and 276 ± 3 MPa, increased by 9.2%, 14.6%,14.2% and 55%, respectively, compared with that of monolithic In718 alloy. The excellent tensile properties of TiC/In718 composite can be ascribed to the combined mechanisms in term of increased dislocation density, dispersive Orowan and load transfer mechanisms.

    Figures and Tables | References | Related Articles | Metrics
    Letter
    Coherent interface strengthening of ultrahigh pressure heat-treated Mg-Li-Y alloys
    Shun Zhang, Yong Sun, Ruizhi Wu, Xiang Wang, Xiao-Bo Chen, Carlos Fernandez, Qiuming Peng
    J. Mater. Sci. Technol., 2020, 51 (0): 79-83.  DOI: 10.1016/j.jmst.2020.02.039
    Abstract   HTML   PDF

    Achieving good strength-ductility of Mg alloys has always been a crucial issue for the widespread applications of Mg-based structural materials. Herein, an unexpected double-stage strengthening phenomenon was discovered in Mg-8Li-1Y(wt.%) alloys through high pressure (6 GPa) heat treatments over a range of 700-1300?°C. Attractively, the yield strength values are improved remarkably without losing their ductility. The low temperature strengthening mechanism is mainly driven by the formation of large-volume nanoscale contraction twins. In contrast, the high-temperature strengthening reason is ascribed to the presence of densely nano-sized stacking faults. Both coherent interfaces contribute effectively to high mechanical strength without any tradeoff in ductility.

    Figures and Tables | References | Related Articles | Metrics
    Research Article
    Phase transformation, thermodynamics and kinetics property of Mg90Ce5RE5 (RE = La, Ce, Nd) hydrogen storage alloys
    Hui Yong, Shihai Guo, Zeming Yuan, Yan Qi, Dongliang Zhao, Yanghuan Zhang
    J. Mater. Sci. Technol., 2020, 51 (0): 84-93.  DOI: 10.1016/j.jmst.2020.02.042
    Abstract   HTML   PDF

    The Mg90Ce5RE5 (RE = La, Ce, Nd) alloys were prepared by a vacuum induction furnace and their microstructure, phase transformation, thermodynamics and kinetics property were systematically studied by XRD, SEM, TEM, and PCT characterization methods. The result shows that the activated alloys are composed of Mg/MgH2 and corresponding REH2+x with nanoscale. The REH2+x grain with Ce and La or Nd functional group have lower nucleation potential barriers than CeH2+x grains as the nucleation location, thus improve the hydrogen absorption kinetics of these alloys among which the Mg90Ce5Nd5 alloy can absorb 90% of the hydrogen within 2 min at 320 oC. In addition, the Mg90Ce10 alloy has the lowest activation energy with 103.2 kJ mol -1 and the fastest desorption kinetics, which can release 5 wt% of the hydrogen within 20 min at 320 oC. This is a correlation with grain size and the in-suit formed CeH2.73/CeO2 interface. Moreover, the co-doping Ce and La or Nd can effectively disorganize the thermodynamic stability of Mg-based hydrogen storage alloys to a certain degree, but the dehydrogenation kinetics of that still is restricted by the recombination energy of hydrogen ions on the surface.

    Figures and Tables | References | Related Articles | Metrics
    One-step fabrication of ultrathin layered 1T@2H phase MoS2 with high catalytic activity based counter electrode for photovoltaic devices
    K. Silambarasan, J. Archana, S. Harish, M. Navaneethan, R. Sankar Ganesh, S. Ponnusamy, C. Muthamizhchelvan, K. Hara
    J. Mater. Sci. Technol., 2020, 51 (0): 94-101.  DOI: 10.1016/j.jmst.2020.01.024
    Abstract   HTML   PDF

    The metallic phase of molybdenum disulfide (M-MoS2) and semiconductor phase of molybdenum disulfide (S-MoS2) was synthesized by hydrothermal method, using cetyltrimethylammonium bromide (CTAB) as a surfactant. The structural and elemental composition confirmed the formation of M-MoS2 and S-MoS2. From the morphological analysis layered nanosheets with an inter-layered distance of 0.62 nm for M-MoS2 and 0.95 nm for S-MoS2 was observed. Fourier-transform infrared (FT-IR) spectral analysis was used to investigate the existence of CTAB functional group. The peak at 885 cm -1 attributed to the CH3 bond which confirmed the presence of CTAB in the S-MoS2. The anodic and cathodic peak separation (Epp) values of the counter electrode (CE) has showed at 468.28 mV (M-MoS2) and 540.87 mV (S-MoS2). The M-MoS2 thin film shows higher catalytic activity when compared to S-MoS2 due to more active sites and electronic conductivity. The power conversion efficiency of M-MoS2 CE based device exhibits higher efficiency compared to S-MoS2 CE based device.

    Figures and Tables | References | Related Articles | Metrics
    Effects of microstructure on the torsional properties of biodegradable WE43 Mg alloy
    Yi Zhang, Lili Tan, Qingchuan Wang, Ming Gao, Iniobong P. Etim, Ke Yang
    J. Mater. Sci. Technol., 2020, 51 (0): 102-110.  DOI: 10.1016/j.jmst.2020.04.003
    Abstract   HTML   PDF

    Torsional properties are important performance parameters for bone screw applications, but they are seldom studied, especially for newly developed biodegradable Mg alloys. In this study, WE43 Mg alloy with different microstructures was achieved by equal channel angular pressing (ECAP) and heat treatment, and their torsional properties were studied. In addition, tensile properties were also tested as a comparison. The results indicated that grain refinement led to higher torsional strength and ductility, while the second phases improved the torsional strength but reduced the ductility. The texture was strengthened after ECAP, as a result the tensile strength increased, but the torsional strength did not increase and even decreased, especially for 2-pass ECAP sample with a typical basal fiber texture. The basal plane orientation deviation from the extrusion direction after 4-pass ECAP resulted in higher torsional strength and lower torsional ductility, but lower tensile strength and higher tensile ductility were obtained. This implied that a strong fiber texture would reduce the torsional strength but improve the torsional ductility, which was different from its effect on tensile properties.

    Figures and Tables | References | Related Articles | Metrics
    Exceptional mechanical properties of AZ31 alloy wire by combination of cold drawing and EPT
    Zhaohui Shan, Jing Bai, Jianfeng Fan, Hongfei Wu, Hua Zhang, Qiang Zhang, Yucheng Wu, Weiguo Li, Hongbiao Dong, Bingshe Xu
    J. Mater. Sci. Technol., 2020, 51 (0): 111-118.  DOI: 10.1016/j.jmst.2020.02.044
    Abstract   HTML   PDF

    A 0.66 mm-diameter AZ31 alloy wire with ultimate tensile strength of 400 MPa and elongation of 28.5% was successfully prepared via the combination of cold-drawing and electropulsing treatment processing (EPT). Microstructure observation showed that the grain size of EPTed samples was refined to about 1 μm and the basal texture strength with maxima texture index was weakened to 7.18. EPT can significantly accelerate recrystallization by enhancing the mobility of dislocation and atomic diffusion due to the coupling of the thermal and athermal effects. Finally, uniform ultrafine-grained structure was obtained in the EPTed samples by static recrystallization completed in a very short time (30 s) at relatively low temperature (433 K).

    Figures and Tables | References | Related Articles | Metrics
    A facile method for preparation of uniformly decorated-spherical SnO2 by CuO nanoparticles for highly responsive toluene detection at high temperature
    Angga Hermawan, Yusuke Asakura, Miki Inada, Shu Yin
    J. Mater. Sci. Technol., 2020, 51 (0): 119-129.  DOI: 10.1016/j.jmst.2020.02.041
    Abstract   HTML   PDF

    We reported a facile preparation of a uniform decoration of spherical n-type SnO2 by p-type CuO nanoparticles as well as their utilization for enhanced performance on toluene gas detection. CuO nanoparticles and spherical SnO2 were synthesized by a facile non-hydrolytic solvothermal reaction, which could easily control their morphology. A uniform CuO nanoparticles decoration onto spherical SnO2 was achieved by a simple sonication and vigorous stirring at room temperature. We revealed organic solvents used in the oxide synthesis had a considerable influence on its surface charge that was beneficial for a uniformly electrostatic self-decoration between positively charged p-type CuO nanoparticles and negatively charged n-type spherical SnO2. Interestingly, CuO was partially reduced to Cu metal during high concentration of toluene exposure destroying p-n contact and developing new metal-semiconductor contact so-called ohmic junction, resulting in extraordinarily responsive and selective to toluene gas at 400 °C as compared to a single p- CuO and n- SnO2. It was also found that the amount of particle decoration had an influence on sensor response and resistance. The optimum amount of CuO nanoparticle decoration was 0.1 mmol on 0.5 mmol SnO2. The response (S = Ra/Rg) and selectivity of CuO/SnO2 based material toward the exposure of 75 ppm toluene had reached to such high as 540 and 5, respectively. The effect of p-n heterojunction and metal-semiconductor contact on the gas sensing mechanism of p-type CuO/n-type SnO2 was discussed. Furthermore, by decorating with CuO nanoparticles, CuO/SnO2 morphology was well-maintained after gas sensing evaluation demonstrated its excellency for high temperature toluene gas sensor application.

    Figures and Tables | References | Related Articles | Metrics
    Influence of refined hierarchical martensitic microstructures on yield strength and impact toughness of ultra-high strength stainless steel
    Haiwen Luo, Xiaohui Wang, Zhenbao Liu, Zhiyong Yang
    J. Mater. Sci. Technol., 2020, 51 (0): 130-136.  DOI: 10.1016/j.jmst.2020.04.001
    Abstract   HTML   PDF

    The hierarchical martensitic features in ultra-high strength stainless steel (UHSSS), including the prior austenite grains, martensite packets, blocks and laths with the descending size, were refined to various extents by employing different thermomechanical processes and then carefully characterized. Their relation to yield strength and impact toughness was analyzed. We conclude that the refinement of martensitic structures could lead to the significant increase of yield strength, which follows the Hall-Petch relation with the effect grain size defined by high angle boundaries (HABs). Impact toughness of UHSSS depends on the frequency and capability for retained austenite (RA) grains at both HABs and martensite lath boundaries to trap the propagating cracks via strain-induced transformation, in which the film-like RA grains at lath boundaries appear to make the greater contribution.

    Figures and Tables | References | Related Articles | Metrics
    Effects of circular beam oscillation technique on formability and solidification behaviour of selective laser melted Inconel 718: From single tracks to cuboid samples
    Huihui Yang, Guanyi Jing, Piao Gao, Zemin Wang, Xiangyou Li
    J. Mater. Sci. Technol., 2020, 51 (0): 137-150.  DOI: 10.1016/j.jmst.2019.09.044
    Abstract   HTML   PDF

    The inherent drawbacks of selective laser melting technique including serious micro-pore and element microsegregation problems destroy the mechanical property of the component. To overcome this problem, a new approach, circular beam oscillation, was successfully applied in the SLMed Inconel 718 samples including single tracks, thin walls and cuboid samples. On one hand, circular beam oscillation reduces the micro-pores in molten pools and cuboid samples, increasing the relative density of the cuboid sample to 99.95 %. On the other hand, circular beam oscillation suppresses the element microsegregation, reducing the formation of Laves phases in SLMed Inconel 718 samples. Moreover, circular beam oscillation enhances the <001> texture of thin walls and the <101> texture of cuboid samples. The improvement of formability and microstructure of the SLMed samples with oscillation is closely related to cooling rate, thermal gradient and stirring effect during the solidification process. Therefore, circular beam oscillation shows the possibility to overcome the key bottlenecks of the traditional SLM technology and to realize a further industrial application of SLM technology.

    Figures and Tables | References | Related Articles | Metrics
    Facilely fabricating superhydrophobic coated-mesh materials for effective oil-water separation: Effect of mesh size towards various organic liquids
    Haifeng Chen, Yizhou Shen, Zhaoru He, Zhengwei Wu, Xinyu Xie
    J. Mater. Sci. Technol., 2020, 51 (0): 151-160.  DOI: 10.1016/j.jmst.2020.03.021
    Abstract   HTML   PDF

    Effective oil-water separation is a continuous pursuit, not only for scientific research but also for engineering application, because oil spills are causing the great pollution in the current ocean environment. Here we reported a superhydrophobic coated-mesh, where the coatings were composed of fluorinated silica (F-SiO2) and polydimethylsiloxane (PDMS), demonstrating the excellent oil-water separation ability towards various organic liquids. The introduction of F-SiO2 could well induce a certain extent of microscopic roughness, leading to the remarkable water repellence. The resultant coatings exhibited the robust superhydrophobicity with the water contact angle reaching 155.9°±1.0°. On this basis, the pore size of polyethylene terephthalate (PET) mesh materials (as a substrate) was mainly discussed with the great oil-water separation efficiency of as high as 98% towards various organic liquids. Also, under the assistance of physical model, it was confirmed that there was a mechanical relation between pore size and organic liquids, where the main connotation was the matching issue of surface tension of organic liquids with the geometrical mechanic (induced by the pore size of the superhydrophobic coated-mesh). This work on the size effect of superhydrophobic coated-mesh materials on various organic liquids is beneficial to the design and manufacture of ideal oil-water separation materials.

    Figures and Tables | References | Related Articles | Metrics
    Letter
    A novel non-stoichiometric medium-entropy carbide stabilized by anion vacancies
    Chong Peng, Hu Tang, Yu He, Xiaoqian Lu, Peng Jia, Guoying Liu, Yucheng Zhao, Mingzhi Wang
    J. Mater. Sci. Technol., 2020, 51 (0): 161-166.  DOI: 10.1016/j.jmst.2020.02.049
    Abstract   HTML   PDF

    Recently, high-entropy ceramics have attracted considerable attentions because of comprehensive physical and chemical properties of high hardness, fracture toughness, and conductivity. However, as a newly emerging class of materials, the synthesis, performance and applications of high-entropy ceramics are subject to further development. Here, we reported a new non-stoichiometric TiC0.4/WC/0.5Mo2C medium-entropy carbide (MEC) with a rock-salt structure. Attributed to the solid solution strengthening and twinning strengthening, the TiC0.4/WC/0.5Mo2C sintered at 1900 °C by spark plasma sintering (SPS) shows superior mechanical behaviors of microhardness (21.7 GPa), which exceeds that expected from the rule of mixture (ROM) of three individual metal carbides (19.1 GPa) and good fracture toughness (5.3 MPa m 1/2). Significantly, the bulk synthesized via high-pressure and high-temperature (HPHT) sintering possesses smaller grain size and shows better comprehensive mechanical properties of microhardness (23.7 GPa) and fracture toughness (6.2 MPa m 1/2). In addition, the effect of anion vacancies on the thermodynamic stability and synthesizability of TiC0.4/WC/0.5Mo2C was analyzed via quantitatively calculated entropy. Vacancies could significantly enhance the configurational entropy of mixing of the solid phase. The introduction of vacancy defects may expand synthetic path for entropy-stabilized ceramics, especially for multi-component high temperature refractory ceramics.

    Figures and Tables | References | Related Articles | Metrics
    Research Article
    Toughening FeMn-based high-entropy alloys via retarding phase transformation
    Ran Wei, Kaisheng Zhang, Liangbin Chen, Zhenhua Han, Chen Chen, Tan Wang, Jianzhong Jiang, Tingwei Hu, Shaokang Guan, Fushan Li
    J. Mater. Sci. Technol., 2020, 51 (0): 167-172.  DOI: 10.1016/j.jmst.2020.02.048
    Abstract   HTML   PDF

    Various high entropy alloys (HEAs) with improved mechanical properties were developed by reducing the phase stability and then promote the phase transformation. The promotion of deformation-induced martensitic transformation from face-centered cubic (fcc) to hexagonal close-packed (hcp) mostly focuses on overcoming the trade-off of strength-ductility of HEAs at room temperature. However, the hcp phase is brittle at cryogenic-temperature, and thus the enhancement of cryogenic ductility of these HEAs still remains a challenge. Here, we present a concept to toughening Fe50Mn30Co10Cr10 HEAs at cryogenic-temperature via retarding phase transformation. The retarded but more persistent phase transformation at high strain level was realized via tailoring the grain size. To further verify the effect of phase transformation rate on ductility of HEAs, the mechanical properties of Fe40Mn40Co10Cr10 HEAs with higher stacking fault energy were tested at room and cryogenic temperature, respectively. The present study sheds light on developing high performance HEAs, especially for alloys with brittle phase transformation products.

    Figures and Tables | References | Related Articles | Metrics
    Spheroidization behaviour of a Fe-enriched eutectic high-entropy alloy
    Yu Yin, Damon Kent, Qiyang Tan, Michael Bermingham, Ming-Xing Zhang
    J. Mater. Sci. Technol., 2020, 51 (0): 173-179.  DOI: 10.1016/j.jmst.2020.01.066
    Abstract   HTML   PDF

    A cost-effective Fe-enriched eutectic high-entropy alloy (EHEA), Fe35Ni25Cr25Mo15, was designed and prepared to avoid the use of expensive Co that is commonly used in HEAs. However, the as-cast Fe-enriched EHEA was associated with brittleness. The present work aims to evaluate the possibility and feasibility of spheroidization of the lamellar structure of the EHEA in order to improve the ductility. Due to the high cooling rate of arc-melting, the as-melted Fe35Ni25Cr25Mo15 EHEA was found to be a pseudo eutectic alloy comprised of alternant σ phase (Cr0.22Mo0.18Fe0.6-type intermetallic) and face centred cubic (FCC) phase. The lamellar structure in the Fe-enriched EHEA remained stable up to 800 °C. The instability of the lamellar structure occurred at temperatures over 800 °C, which was resulted from migration of high-density faults (i.e. lamellar termination and ledges in the lamellae). However, the Fe35Ni25Cr25Mo15 EHEA still exhibited brittleness even after spheroidization at 1100 °C for 168 h due to the formation of the hard and brittle σ matrix in the pseudo Fe35Ni25Cr25Mo15 EHEA as a result of decomposition of the lamellar structure. Therefore, in contrast to the softening of traditional eutectic alloys, spheroidization treatment was considered as invalid to improve the ductility of pseudo-eutectic HEA with high fraction of intermetallic phase. The present work provides a valuable reference for those who aim to improve the ductility of brittle EHEA through spheroidization.

    Figures and Tables | References | Related Articles | Metrics
    A DFT study on brittle-to-ductile transition of D022-TiAl3 using multi-doping and strain-engineered effects
    Boon Teoh Tan, Shunnian Wu, Franklin Anariba, Ping Wu
    J. Mater. Sci. Technol., 2020, 51 (0): 180-192.  DOI: 10.1016/j.jmst.2020.02.053
    Abstract   HTML   PDF

    In this work, the thermodynamic, mechanical properties and electronic behaviors of D022-TiAl3 doped with W and 15 group IV M (M C, Ge, Pb, Si and Sn) dopants are investigated by DFT methods. We established that ductility can be improved using multi-doping approach and revealed the mechanisms behind such brittle-to-ductile transition. In addition, it is found that there is linearity between changes in Young’s modulus and tensile/compressive strain ratio. An alternate insight into brittle-to-ductile transition during ductile mode cutting of brittle materials is proposed.

    Figures and Tables | References | Related Articles | Metrics
    Characterization of lattice parameters gradient of Cu(In1-xGax)Se2 absorbing layer in thin-film solar cell by glancing incidence X-ray diffraction technique
    Yong-Il Kim, Ki-Bok Kim, Miso Kim
    J. Mater. Sci. Technol., 2020, 51 (0): 193-201.  DOI: 10.1016/j.jmst.2020.04.004
    Abstract   HTML   PDF

    In or Ga gradients in the Cu(In1-xGax)Se2 (CIGS) absorbing layer lead to change the lattice parameters of the absorbing layer, giving rise to the bandgap grading in the absorbing layer which is directly associated with the degree of absorbing ability of the CIGS solar cell. We tried to characterize the depth profile of the lattice parameters of the CIGS absorbing layer using a glancing incidence X-ray diffraction (GIXRD) technique, and then investigate the bandgap grading of the CIGS absorbing layer. When the glancing incident angle increased from 0.50 to 5.00°, the a and c lattice parameters of the CIGS absorbing layer gradually decreased from 5.7776(3) to 5.6905(2) ?, and 11.3917(3) to 11.2114(2) ?, respectively. The depth profile of the lattice parameters as a function of the incident angle was consistent with vertical variation in the compositionof In or Ga with depth in the absorbing layer. The variation of the lattice parameters was due to the difference between the ionic radius of In and Ga co-occupying at the same crystallographic site. According to the results of the depth profile of the refined parameters using GIXRD data, the bandgap of the CIGS absorber layer was graded over a range of 1.222-1.532 eV. This approach allows to determine the In or Ga gradients in the CIGS absorbing layer, and to nondestructively guess the bandgap depth profile through the refinement of the lattice parameters using GIXRD data on the assumption that the changes of the lattice parameters or unit-cell volume follow a good approximation to Vegard’s law.

    Figures and Tables | References | Related Articles | Metrics
ISSN: 1005-0302
CN: 21-1315/TG
Home
About JMST
Privacy Statement
Terms & Conditions
Editorial Office: Journal of Materials Science & Technology , 72 Wenhua Rd.,
Shenyang 110016, China
Tel: +86-24-83978208
E-mail:JMST@imr.ac.cn

Copyright © 2016 JMST, All Rights Reserved.