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| 1 | Antibacterial metals and alloys for potential biomedical implants显示文摘Metals and alloys,including stainless steel,titanium and its alloys,cobalt alloys,and other metals and alloys have been widely used clinically as implant materials,but implant-related infection or inflammation is still one of the main causes of implantation failure.The bacterial infection or inflammation that seriously threatens human health has already become a worldwide complaint.Antibacterial metals and alloys recently have attracted wide attention for their long-term stable antibacterial ability,good mechanical properties and good biocompatibility in vitro and in vivo.In this review,common antibacterial alloying elements,antibacterial standards and testing methods were introduced.Recent developments in the design and manufacturing of antibacterial metal alloys containing various antibacterial agents were described in detail,including antibacterial stainless steel,antibacterial titanium alloy,antibacterial zinc and alloy,antibacterial magnesium and alloy,antibacterial cobalt alloy,and other antibacterial metals and alloys.Researches on the antibacterial properties,mechanical properties,corrosion resistance and biocompatibility of antibacterial metals and alloys have been summarized in detail for the first time.It is hoped that this review could help researchers understand the development of antibacterial alloys in a timely manner,thereby could promote the development of antibacterial metal alloys and the clinical application. | Erlin Zhang Xiaotong Zhao Jiali Hu Ruoxian Wang Shan Fu Gaowu Qin | 2021 | Bioactive Materials2021,6,8: | 13 |
| 2 | Indirectly extruded biodegradable Zn-0.05wt%Mg alloy with improved strength and ductility: In vitro and in vivo studies显示文摘As compared to permanent orthopedic implants for load-bearing applications, biodegradable orthopedic implants have the advantage of no need for removing after healing, but they suffer from the 'trilemma' problem of compromising among sufficiently high mechanical properties, good biocompatibility and proper degradation rate conforming to the growth rate of new bones. In the present work, in vitro and in vivo studies of a Zn-0.05 wt%Mg alloy(namely, Zn-0.05 Mg alloy) were conducted with pure Zn as a control. The Zn-0.05 Mg alloy is composed of a small amount of Mg_2 Zn11 phase embedded in the refined Zn matrix with an average grain size of ~20 μm. The addition of 0.05 wt% Mg into Zn significantly increases the ultimate tensile strength up to 225 MPa and the elongation to fracture to 26%, but has little influence on the in vitro degradation rate. Both Zn and Zn-0.05 Mg alloy exhibit homogeneous in vitro degradation with a rate of about 0.15 mm/year. Based on the cytotoxicity evaluation, Zn and Zn-0.05 Mg alloy do not induce toxicity to L-929 cells, indicating that they have little toxicity to the general functions of the animal. An in vivo biocompatibility study of Zn and Zn-0.05 Mg alloy samples by placing them in a rabbit model for 4.12 and 24 weeks, respectively did not show any inflammatory cells, and demonstrated that new bone tissue formed at the bone/implant interface, suggesting that Zn and Zn-0.05 Mg alloy promote the formation of new bone tissue. The in vivo degradation of Zn and Zn-0.05 Mg alloy does not bring harm to the important organs and their cell structures. More interestingly, Zn and Zn-0.05 Mg alloy exhibit strong antibacterial activity against Escherichia coli and Staphylococcus aureus. The above results clearly demonstrate that the Zn-0.05 Mg alloy could be a potential biodegradable orthopedic implant material. | Chi Xiao Liqing Wang Yuping Ren Shineng Sun Erlin Zhang Chongnan Yan Qi Liu Xiaogang Sun Fenyong Shou Jingzhu Duan Huang Wang Gaowu Qin | 2018 | Journal of Materials Science & Technology2018,34,9: | 11 |
| 3 | Effect of extrusion speed on microstructure and mechanical properties of the Mg-Ca binary alloy显示文摘This work reported the effect of extrusion speeds on the microstructures and mechanical properties of Mg-Ca binary alloy.The results showed that yield strength of the as-extruded Mg-1.2wt.%Ca alloys decrease from∼360MPa to∼258MPa as the ram speed increases from 0.4mm/s to 2.4 mm/s,and the elongation increases from∼3.9%to∼12.2%.The microstructure changes from bimodal grain feature to the complete dynamical recrystallization(DRX)with increase of the extrusion speed.The ultrafine DRXed grains in size of∼0.85μm,the numerous nano-Mg_(2)Ca particles dispersing along the grain boundaries and interiors,as well as the high density of residual dislocations,should account for the high strength.It is believed that the high degree of dynamic recrystallization and the resulting texture randomization play the critical roles in the ductility enhancement of the high-speed extruded Mg alloys. | Jingren Li Aiyue Zhang Hucheng Pan Yuping Ren Zhuoran Zeng Qiuyan Huang Changlin Yang Lifeng Ma Gaowu Qin | 2021 | Journal of Magnesium and Alloys2021,9,4: | 9 |
| 4 | Optimization of mechanical properties, biocorrosion properties and antibacterial properties of wrought Ti-3Cu alloy by heat treatment显示文摘Previous study has shown that Ti-3Cu alloy shows good antibacterial properties(>90%antibacterial rate),but the mechanical properties still need to be improved.In this paper,a series of heat-treatment processes were selected to adjust the microstructure in order to optimize the properties of Ti-3Cu alloy.Microstructure,mechanical properties,biocorrosion properties and antibacterial properties of wrought Ti-3Cu alloy at different conditions was systematically investigated by X-ray diffraction,optical microscope,scanning electron microscope,transmission electron microscopy,electrochemical measurements,tensile test,fatigue test and antibacterial test.Heat treatment could significantly improve the mechanical properties,corrosion resistance and antibacterial rate due to the redistribution of copper elements and precipitation of Ti2Cu phase.Solid solution treatment increased the yield strength from 400 to 740MPa and improved the antibacterial rate from 33%to 65.2%while aging treatment enhanced the yield strength to 800e850MPa and antibacterial rate(>91.32%).It was demonstrated that homogeneous distribution and fine Ti2Cu phase plays a very important role in mechanical properties,corrosion resistance and antibacterial properties. | Mianmian Bao Ying Liu Xiaoyan Wang Lei Yang Shengyi Li Jing Ren Gaowu Qin Erlin Zhang | 2018 | Bioactive Materials2018,3,1: | 7 |
| 5 | Microstructural and mechanical response of ZK60 magnesium alloy subjected to radial forging显示文摘Radial forging(RF)is an economical manufacturing forging process,in which four dies arranged radially around the workpiece simultaneously act on the workpiece with high-frequency radial movement.In this study,a ZK60 magnesium alloy step-shaft bar was processed under different accumulated strains by RF at350℃.The deformation behavior,microstructure evolution,and mechanical responses of this bar were systematically investigated via numerical simulations and experiments.At the early deformation stage of forging,the material undergoes pronounced grain refinement but an inhomogeneous grain structure is formed due to the strain gradient along the radial direction.The grains in different radial parts were gradually refined by increasing the RF pass,resulting in a bimodal grained structure comprising coarse(~14.1μm)and fine(~2.3μm)grains.With the RF pass increased,the initial micro-sizeβ-phases were gradually crushed and dissolved into the matrix mostly,eventually evolving to form a higher area fraction of nano-sized Zn2 Zr spheroidal particles uniformly distributed through the grain interior.The texture changed as the RF strain increased,with the c-axes of most of the deformed grains rotating in the RD.Additionally,excellent mechanical properties including higher values of tensile strengths and ductility were attained after the three RFed passes,compared to the as-received sample. | Jingfeng Zou Lifeng Ma Weitao Jia Qichi Le Gaowu Qin Yuan Yuan | 2021 | Journal of Materials Science & Technology2021,,24: | 4 |
| 6 | Hot deformation behavior of an antibacterial Co–29Cr–6Mo–1.8Cu alloy and its effect on mechanical property and corrosion resistance显示文摘In order to optimize the deformation processing, the hot deformation behavior of Co–Cr–Mo–Cu(hereafter named as Co–Cu) alloy was studied in this paper at a deformation temperature range of 950–1150°C and a strain rate range of 0.008–5 s^(-1). Based on the true stress–true strain curves, a constitutive equation in hyperbolic sin function was established and a hot processing map was drawn. It was found that the flow stress of the Co–Cu alloy increased with the increase of the strain rate and decreased with the increase of the deforming temperature. The hot processing map indicated that there were two unstable regions and one well-processing region. The microstructure, the hardness distribution and the electrochemical properties of the hot deformed sample were investigated in order to reveal the influence of the hot deformation. Microstructure observation indicated that the grain size increased with the increase of the deformation temperature but decreased with the increase of the strain rate. High temperature and low strain rate promoted the crystallization process but increased the grain size, which results in a reduction in the hardness. The hot deformation at high temperature(1100–1150°C) would reduce the corrosion resistance slightly. The final optimized deformation process was: a deformation temperature from 1050 to 1100°C, and a strain rate from 0.008 to 0.2 s^(-1), where a completely recrystallized and homogeneously distributed microstructure would be obtained. | Erlin Zhang Yang Ge Gaowu Qin | 2018 | Journal of Materials Science & Technology2018,34,3: | 4 |
| 7 | A novel biomedical titanium alloy with high antibacterial property and low elastic modulus显示文摘β-type titanium alloys have attracted much attention as implant materials because of their low elastic modulus and high strength,which is closer to human bones and can avoid the problem of stress fielding and extend the lifetime of prosthetics.However,other issues,such as the infection or inflammation postimplantation,still trouble the titanium alloy's clinical application.In this paper,we developed a novel nearβ-titanium alloy(Ti-13Nb-13Zr-13Ag,TNZA)with low elastic modulus and strong antibacterial ability by the addition of Ag element followed by proper microstructure controlling,which could reduce the stress shielding and bacterial infections simultaneously.The microstructure,mechanical properties,corrosion resistance,antibacterial properties and cell toxicity were studied using SEM,electrochemical testing,mechanical test and cell tests.The results have demonstrated that TNZA alloy exhibited an elastic modulus of 75-87 GPa and a strong antibacterial ability(up to 98%reduction)and good biocompatibility.Moreover,it was also shown that this alloy's corrosion resistance was better than that of Ti-13Nb-13Zr.All the results suggested that Ti-13Nb-13Zr-13Ag might be a competitive biomedical titanium alloy. | Diangeng Cai Xiaotong Zhao Lei Yang Renxian Wang Gaowu Qin Da-fu Chen Erlin Zhang | 2021 | Journal of Materials Science & Technology2021,,22: | 4 |
| 8 | Low-cost and high-strength Mg-Al-Ca-Zn-Mn wrought alloy with balanced ductility显示文摘A novel low-cost Mg-Al-Ca-Zn-Mn-based alloy was developed to simultaneously improve its strength and ductility.The high yield strength of 411 MPa and the high elongation to failure of~8.9%have been achieved in the as-extruded Mg-1.3Al-1.2Ca-0.5Zn-0.6Mn(wt%)sample.Microstructure characterizations showed that the high strength is mainly associated with the ultra-fined dynamically recrystallized(DRXed)grains.Moreover,high-density dislocations in the un-DRXed region and nano-precipitates are distributed among theα-Mg matrix.The high ductility property can be ascribed to the high volume fraction of DRXed grains with a much randomized texture,as well as the formations of high-density subgrains in the un-DRXed grain regions. | Kun Yang Hucheng Pan Sen Du Man Li Jingren Li Hongbo Xie Qiuyan Huang Huajun Mo Gaowu Qin | 2022 | International Journal of Minerals,Metallurgy and Materials2022,29,7: | 3 |
| 9 | Improvement of microstructure and fatigue performance of wire-arc additive manufacture d 4043 aluminum alloy assiste d by interlayer friction stir processing显示文摘To expand the application of wire-arc additive manufacturing(WAAM)in aluminum alloy forming com-ponents,it is vitally important to reduce the porosity,refine microstructure,and thereby improve the mechanical properties of the components.In this study,the interlayer friction stir processing(FSP)tech-nique was employed to assist the WAAM of 4043 Al-Si alloy,and the related effects on the microstruc-ture evolutions and mechanical properties of the fabricated builds were systematacially investigated.As compared to the conventional WAAM processing of Al-Si alloy,it was found that the introduction of in-terlayer FSP can effectively eliminate the pores,and both theα-Al dendrites and Si-rich eutectic network were severely broken up,leading to a remarkable enhancement in ductility and fatigue performance.The average yield strength(YS)and ultimate tensile strength(UTS)of the Al-based components produced by the combination of WAAM and interlayer FSP methods were 88 and 148 MPa,respectively.Meanwhile,the elongation(EL)of 37.5%and 28.8%can be achieved in the horizontal and vertical directions,respec-tively.Such anisotropy of EL was attributed to the inhomogeneous microstructure in the stir zone(SZ).Notably,the stress concentration can be effectively reduced by the elimination of porosity and Si-rich eu-tectic network fragmentation by the interlayer FSP,and thus the fatigue behavior was improved with the fatigue strength and elongation increased by∼28%and∼108.7%,respectively.It is anticipated that this study will provide a powerful strategy and theoretical guidance for the WAAM fabrication of Al-based alloy components with high ductility and fatigue performance. | Changshu He Jingxun Wei Ying Li Zhiqiang Zhang Ni Tian Gaowu Qin Liang Zuo | 2023 | Journal of Materials Science & Technology2023,,2: | 2 |
| 10 | Effect of Cu on Martensite Transformation of CoCrMo alloy for biomedical application显示文摘The martensite transformation of Co-29Cr-6Mo-xCu(Co-xCu,x=0,1.5,2,4,wt%)alloys was investigated in order to explore ductile Co-based alloy without Ni for biomedical application.The effect of Cu on martensite transformation of Co-29 Cr-6 Mo alloy was investigated using scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-Ray diffraction(XRD)and electron backscatter diffraction(EBSD)analysis.EBSD results revealed that the fraction ofγ-phase was increasing with increasing of copper content.In detail,the fraction ofγ-phase of aged Co-1.5 Cu alloy was 4.72%and noγ-phase was found in aged Co-0Cu alloy.Furthermore,the fraction ofγ-phase of aged Co-2Cu alloy and Co-4Cu alloy was 51.68%and 46.17%,respectively.This demonstrated that the minimum Cu content which could inhibit martensite transformation in this alloy system was 2 wt%.Calculated phase diagram revealed that increasing the copper content of this alloy system could enlargeγ-phase zone,which means Cu could inhibit the formation ofγ-phase and consequently stabilizeγ-phase.Randomly distributed Cu-rich phase was identified in aged Co-4Cu alloy.The possible reason for the inhibition of martensite transformation by Cu addition is that alloying with Cu atom might decrease charge accumulations and increase atomic bonds,which increase the stacking fault energy ultimately. | Ruoxian Wang Gaowu Qin Erlin Zhang | 2020 | Journal of Materials Science & Technology2020,52,17: | 2 |
| 11 | Nucleation and growth mechanisms of γ〞 phase with single-unit-cell height in Mg-RE-Zn(Ag) series alloys: a first-principles study显示文摘The highly thermal stability precipitates strengthen creep resistance for alloys,which require precipitates to resist coarsen at elevated temperature.In the Mg-RE-Zn(Ag)series alloys,the key strengthening phase-γ'phase,remains its single-unit-cell height throughout aging process.The origin of such extremely thermal stability ofγ'phase is still unclear.By using the first-principles calculations,it is found that the formation ofγ'phase introduces compressive strain to its surroundingα-Mg lattice and simultaneously alter charge distribution ofα-Mg lattice near theα-Mg/γ'hetero-interface.These two variations overα-Mg lattice lead to lower vacancy formation energies and migration energy barriers for solute atoms near theα-Mg/γ'hetero-interface in comparison with that of bulk condition.Consequently,the variations facilitate rapid diffusion of solute atoms near theγ'phase and promote nucleation rate of otherγ'plates around it.On the basis of ledge-thickening model,the origin of nucleation/growth ofγ'phase with single-unit-cell height was explained.Thermodynamically and kinetically,the solute atoms are not apt to migrate into the nearest basal plane adjacent to theγ'phase.Moreover,the lower aging temperature(~200℃)and almost completely coherentα-Mg/γ'hetero-interface lead to the ledges are extremely hard to nucleate on the hetero-interface.Therefore,γ'plates maintain single-unit-cell height throughout aging process. | Junyuan Bai Hongbo Xie Xueyong Pang Guo Yuan Lei Wang Yuping Ren Gaowu Qin | 2021 | Journal of Materials Science & Technology2021,,20: | 1 |
| 12 | Hot-top direct chill casting assisted by a twin-cooling field:Improving the ingot quality of a large-size 2024 Al alloy显示文摘Microstructure inhomogeneity and negative segregation have long been challenges for large-size alloy ingots,directly affecting the downstream processing and final performance of products.Here,we used2024 aluminum alloy as a model alloy to propose a technique,named double-cooling field casting,i.e.,one 2024 Al alloy rod(Φ20 mm)at room temperature was introduced into the melt along the central axis of the hot-top with the protection of a thermal-insulation tube during the direct chill(DC)casting process of aΦ300 mm 2024 Al alloy ingot.The results show that the introduction of the same alloy solid insert has a remarkable influence on refining grains in the center region of the ingot,reducing negative centerline segregation and decreasing the depth of the center part of the sump.With the application of the 2024 Al insert,the mean size of equiaxed grains at the center part of the ingot decreased from1204±132μm to 721±69μm.The relative deviation of the Cu and Mg main solutes reduced from-0.062 and-0.054 to-0.03 and-0.024,respectively,and the sump depth decreased from 280 mm to242 mm.Moreover,the shape of the solidification front was changed from‘V’-shaped to‘W’-shaped.The ingot quality was thus improved,mainly arising from the dissolution of the cold 2024 Al insert at a proper position of the hot-top counteracting some latent heat of solidification of the ingot,dissipating the heat of the central part of the hot-top by conducting the 2024 Al insert to the outside,and providing extra-nuclei from the unmoltenα-Al particles of the insert. | Cheng Zhu Zhihao Zhao Qingfeng Zhu Gaosong Wang Yubo Zuo Qiangqiang Li Gaowu Qin | 2022 | Journal of Materials Science & Technology2022,,17: | 1 |
| 13 | High-entropy-alloy nanoparticles with 21 ultra-mixed elements for efficient photothermal conversion显示文摘Multi-metallic nanoparticles have been proven to be an efficient photothermal conversion material, for which the optical absorption can be broadened through the interband transitions(IBTs), but it remains a challenge due to the strong immiscibility among the repelling combinations. Here, assisted by an extremely high evaporation temperature, ultra-fast cooling and vapor-pressure strategy, the arc-discharged plasma method was employed to synthesize ultra-mixed multi-metallic nanoparticles composed of 21 elements(FeCoNiCrYTiVCuAlNbMoTaWZnCdPbBiAgInMnSn), in which the strongly repelling combinations were uniformly distributed. Due to the reinforced lattice distortion effect and excellent IBTs, the nanoparticles can realize an average absorption of >92% in the entire solar spectrum(250 to 2500 nm). In particular, the 21-element nanoparticles achieve a considerably high solar steam efficiency of nearly 99%under one solar irradiation, with a water evaporation rate of 2.42 kg mh, demonstrating a highly efficient photothermal conversion performance. The present approach creates a new strategy for uniformly mixing multi-metallic elements for exploring their unknown properties and various applications. | Yijun Liao Yixing Li Rongzhi Zhao Jian Zhang Lizhong Zhao Lianze Ji Zhengyu Zhang Xiaolian Liu Gaowu Qin Xuefeng Zhang | 2022 | National Science Review2022,9,6: | 1 |
| 14 | Anomalous crystal structure of γ' phase in the Mg-RE-Zn(Ag) series alloys:Causality clarified by ab initio study显示文摘The crystal structure of the single-unit-cell thickness γ ' phase,as a key strengthening phase in Mg-REZn(Ag) series alloys,has been extensively studied,and several structural models have been proposed in the past two decades.However,these reported models,and even the lattice constants at the same proposed structure,are scattered severely,which has led to considerable confusion and not available for further mechanical property simulation and prediction of Mg alloys containing this phase.In this study,by using first-principles calculations,the crystal structure of y' phase is clarified,resolving the discrepancies among different experiments,and its intrinsic mechanical properties have also been studied for the first time.It is verified that the γ ' phase contains quasi-five atomic layers,instead of the previously reported tri-layer,and surprisingly,its crystal structure has many variants,which would change with the alloy composition.Besides,with the help of the simulated selected area electron diffraction(SAED) patterns,it is found that the atoms in the central layer remain partially ordered distribution,and this ordered extent primarily depends on the atomic ratio of RE:Zn(Ag) and the solute content in an alloy.That is,the ordered extent increases with decreasing the atomic ratio of RE:Zn(Ag) and/or increasing solute content of alloy,and vice versa.Ag and Zn dissolved in the γ' phase would produce almost opposed mechanical anisotropy for the γ ' phase under the identical crystal structure,and the addition of Ag shows more efficient on increasing the shear modulus of γ' phase. | Junyuan Bai Xueyong Pang Xiangying Meng Hongbo Xie Hucheng Pan Yuping Ren Min Jiang Gaowu Qin | 2020 | Journal of Materials Science & Technology2020,36,1: | 1 |
| 15 | Microstructure and tensile properties of as-extruded Mg-Sn-Y alloys 显示文摘 | Zhao Hongda Qin Gaowu Ren Yuping | 2010 | Transactions of Nonferrous Metals Society of China2010,20,: | 1 |
| 16 | Natural diatomite particles: Size-, dose- and shape- dependent cytotoxicity and reinforcing effect on injectable bone cement显示文摘Natural diatomite(DT) is the ancient deposit of diatom skeleton with many regular pores of 50–200 nm and also an abundant source of biogenic silica. Although silica is considered biologically safe and there is an increasing interest of using natural diatomite for biomedical applications, the toxicity information about natural diatomite is still missing. Here, cytotoxicity of natural diatomite on osteoblasts and fibroblasts were compared to hydroxyapatite and the relationships between cytotoxicity and diatomite sizes, dose, geometry or impurity were systematically investigated. Cell adhesion and interaction with diatomite particles were also fluorescently observed. The results clearly suggested a size-, dose-and shape-dependent cytotoxicity of natural diatomite. Disk-shaped diatomite particles with average size of30 um in diameter revealed the least toxicity, while the diatomite particles with irregular shapes and sizes less than 10 um were remarkably toxic. Diatomite particles with proper sizes were then selected to investigate the reinforcing effect on injectable calcium phosphate bone cement. Results showed that diatomite significantly improved the compressive strength of bone cement but did not alter the injectability of the cement. This work provided important biocompatibility information of natural diatomite and demonstrated the feasibility of using selected diatomite as bone implant material. | Xiang Zhang Huilin Yang Song Li Gaowu Qin Lei Yang | 2018 | Journal of Materials Science & Technology2018,34,6: | 1 |
| 17 | Structural and Morphological Modulation of BiOCl Visible-light Photocatalyst Prepared via an In situ Oxidation Synthesis显示文摘 | WANG Jianmin CAO Feng DENG Ruiping HUANG Lijian LI Song CAI Jiajia LU Xin QIN Gaowu | 2016 | Chemical Research in Chinese Universities2016,32,3: | 1 |
| 18 | Enhancing the mechanical performance of Al-Zn-Mg alloy builds fabricated via underwater friction stir additive manufacturing and post-processing aging显示文摘Our previous studies have demonstrated that underwater friction stir additive manufacturing(FSAM)could effectively suppress the macroscale softening of the fabricated Al-Zn-Mg-Cu alloy build from top to bottom.However,the accompanying local softening problem,i.e.,a low-hardness region at the bottom of each stir zone,becomes prominent.In this study,an Al-Zn-Mg alloy with low quench sensitivity was used to fabricate a multilayered build via underwater FSAM.In-process water cooling could effectively solve the macroscale and local softening problems in the FSAM of the Al-Zn-Mg alloy and improve the mechanical performance of the build.The microhardness and ultimate tensile strength(UTS)of the water-cooled build in as-fabricated and aged states were more uniform along the building direction and higher than those of their counterparts.After 90 days of natural aging,the UTS of the water-cooled build in building and traveling directions reached 398 and 400 MPa,respectively,slightly higher than that of the base metal(392 MPa).The enhancement in the mechanical performance of the water-cooled build was attributed to a high degree of supersaturation and age-strengthening ability because of a high cooling rate of the underwater FSAM process and low quench sensitivity of the base metal. | Changshu He Ying Li Jingxun Wei Zhiqiang Zhang Ni Tian Gaowu Qin Xiang Zhao | 2022 | Journal of Materials Science & Technology2022,,13: | 1 |
| 19 | Towards ultrastrong and ductile medium-entropy alloy through dual-phase ultrafine-grained architecture显示文摘Advanced materials with superior comprehensive mechanical properties are strongly desired,but it has long been a challenge to achieve high ductility in high-strength materials.Here,we proposed a new V 0.5 Cr 0.5 CoNi medium-entropy alloy(MEA)with a face-centered cubic/hexagonal close-packed(FCC/HCP)dual-phase ultrafine-grained(UFG)architecture containing stacking faults(SFs)and local chemical order(LCO)in HCP solid solution,to obtain an ultrahigh yield strength of 1476 MPa and uniform elongation of 13.2%at ambient temperature.The ultrahigh yield strength originates mainly from fine grain strength-ening of the UFG FCC matrix and HCP second-phase strengthening assisted by the SFs and LCO inside,whereas the large ductility correlates to the superior ability of the UFG FCC matrix to storage disloca-tions and the function of deformation-induced SFs in the vicinity of the FCC/HCP boundary to eliminate the stress concentration.This work provides new guidance by engineering novel composition and stable UFG structure for upgrading the mechanical properties of metallic materials. | Zhen Chen Hongbo Xie Haile Yan Xueyong Pang Yuhui Wang Guilin Wu Lijun Zhang Hu Tang Bo Gao Bo Yang Yanzhong Tian Huiyang Gou Gaowu Qin | 2022 | Journal of Materials Science & Technology2022,,31: | 1 |
| 20 | Achieving high strength above 400 MPa in conventionally extruded Mg-Ca-Zn ternary alloys显示文摘In this work,the role of Zn content in modifying the microstructure and mechanical properties of the Mg-1.2Ca-xZn(x=0.6,2.0 wt.%,named as XZ10-0 and ZX21-0,respectively)based alloys was studied,and it is found that the yield strength(YS)of the present Mg-(Zn)-Ca based alloys increases monotonically with increasing the Zn concentration,from~339 MPa in low-Zn content XZ10-0 sample to~406 MPa in high-Zn content ZX21-0 sample.Microstructure characterization shows that the enhanced YS can be attributed to the grain refinement,fine and dispersed nano-phases,a large number of lamellae structures,and the decrease of recrystallization fraction.TEM results show that the formation mechanism for the ultra-fine grains in present Mg-(Zn)-Ca based alloys can be attributed to the co-segregation of Ca and Zn elements at the grain boundary,as well as the dynamic nanoprecipitations.When the Zn content is high,the nano-phases in ZX21-0 sample belong to the Ca;Mg;Zn;ternary phases,which exert much higher thermal stability than the nano-sized Mg2 Ca binary phases formed in the low-Zn content XZ10-0 sample.The finer size and higher number density of the nano-Mg Zn Ca phases lead to the much finer grain size and sub-grain lamellae thickness in ZX21-0 sample,which thus results in the higher YS of~406 MPa. | DU Sen YANG Kun LI Man LI JingRen REN YuPing HUANG QiuYan PAN HuCheng QIN GaoWu | 2022 | Science China(Technological Sciences)2022,65,3: | 1 |