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Journal of Materials Science & Technology 2023年第20期151卷 30-40页

作者： You Wang Zhangjian Zhou Hui Wang Jiang Ju Zhao Shen Xiaoqin ZENG School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China Interdisciplinary Materials Research Center Institute for Advanced StudyChengdu UniversityChengdu 610041China School of Materials Science and Engineering Shanghai Jiao Tong UniversityNo.800 Dongchuan RoadShanghai 200240China

The worn scars on Alloy 690 after the fretting corrosion testing in simulated pressurized water reactor(PWR)secondary water have been comprehensively analyzed by scanning transmission electron microscopy(STEM)and transmission Kikuchi diffraction(TKD).The high-quality characterization results experimentally show that the fretting wear accelerates the corrosion of Alloy 690 in two approaches.The first one is to break the integrity of the oxide scale by introducing cavities at the oxide grain boundaries.The second one is to alter the microstructure of the underneath matrix,forming a nano-grained matrix layer.The increased grain boundary density in this layer can accelerate the consumption of Cr in the near-surface matrix.The loss of oxide scale integrity and the accelerated Cr consumption are believed to contribute to the deteriorated corrosion resistance of Alloy 690 during the fretting corrosion process.

关键词： Alloy 690 Corrosion Fretting wear Transmission electron microscopy Transmission Kikuchi Diffraction

Dominant Deformation Mechanisms in Mg–Zn–Ca Alloy

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Acta Metallurgica Sinica(English Letters) 2022年第12期35卷 1973-1982页

作者： Tao Ying Mingdi Yu Yiwen Chen Huan Zhang Jingya Wang Xiaoqin ZENG National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240China

The coaddition of Zn and Ca has great potential to improve the ductility of Mg alloys.Herein,the mechanical properties of an extruded Mg-Zn-Ca solid-solution alloy were studied by quasi-in situ electron backscatter diffraction(EBSD)-assisted slip trace analysis.The dominant deformation mechanisms of the Mg-Zn-Ca alloy were studied,and the origins of enhanced ductility were systematically revealed.The results indicate that most grains deformed by basal slip.In addition,multiple non-bas al slip traces were detected(particularly prismatic,pyramidal I,and pyramidal Islip traces),and their activation frequency was promoted with increasing tensile strain.The enhanced participation of non-basal slip systems is believed to play a critical role in achieving homogeneous plastic deformation,thus effectively promoting the ductility of the Mg-Zn-Ca alloy.Furthermore,first-principle calculations revealed that the coaddition of Zn and Ca significantly reduces the unstable stacking fault energy for non-basal slip,which contributes to the activation of non-basal slip systems during plastic deformation.

关键词： Mg-Zn-Ca alloy Non-basal slip activities First-principle calculations Generalized stacking fault energy Deformation mechanisms

Phase equilibria of long-period stacking ordered phase in the ternary Mg-Y-Al alloys

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Journal of Materials Science & Technology 2022年第31期126卷 80-92页

作者： Yiwen Chen Quan Li Yangxin Li Weisen Zheng Jingya Wang Xiaoqin ZENG National Engineering Research Center of Light Alloy Net Forming Shanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Advanced Special Steels School of Materials Science and EngineeringShanghai UniversityShanghai 200444China

Phase equilibria focusing on the long-period stacking ordered(LPSO)phases have been experimentally in-vestigated in the Mg-Y-Al alloys.The microstructures of the eleven representative alloys annealed at 450,500 and 550°C were systematically investigated using X-ray diffraction(XRD),scanning electron mi-croscopy(SEM)and transmission electron microscopy(TEM).Two thermodynamically stable LPSO poly-types were identified,including 18R and 10H structures.Meanwhile,the transformation of 18R→10H was detected in Mg-9.0Y-1.7Al(at.%)alloy,while the coexistence of 18R and 10H was observed in Mg-14.2Y-12.8Al(at.%)alloy.It was found that the LPSO phases were non-stoichiometric compounds with ternary solubilities.The 18R can dissolve up to 7.21 at.%-8.37 at.%Al and 10.75 at.%-12.01 at.%Y,while the 10H can dissolve up to 9.35 at.%-10.37 at.%Al and 14.50 at.%-14.94 at.%Y.All of the experimental re-sults were used to construct the isothermal sections,which is conducive to the design of Mg-Y-Al alloys.

关键词： Mg-Y-Al alloys LPSO phases Phase relationships Isothermal sections Atomic structure

A hot tearing criterion based on solidifcation microstructure in cast alloys

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Journal of Materials Science & Technology 2022年第10期105卷 68-80页

作者： Bo Hu Zixin Li Dejiang Li Tao Ying Xiaoqin ZENG Wenjiang Ding National Engineering Research Center of Light Alloy Net Forming School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China The State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240China

A criterion based on solidifcation microstructure was proposed to precisely predict the hot tearing behavior of cast alloys,which takes into account the effects of both mechanical and nonmechanical factors.This criterion focuses on the events occurring at the grain boundary,which are determined by the thermal contraction,solidifcation shrinkage,grain growing and liquid feeding.This criterion responds to a series of factors that affect hot tearing,such as alloy composition,mold design,casting process and microstructure.Its credibility has been validated by studying the hot tearing behavior of Mg-Ce alloys.In conformity with the experimental results,this criterion predicted decrease in the number of rods occurring hot tearing with increasing cerium content.A simplifed criterion was derived and validated by Mg-Ce(equiaxed grain)and Mg-Al(columnar grain)alloy systems,which is suitable for the case where the eutectic liquid fraction is low and the liquid feeding can be ignored.In addition,a hot tearing index for equiaxed grains was proposed,that is,|d T/d(f_(s)^(1/3)near(f_(s))^(1/3)=1,and its prediction results were consistent with the hot tearing susceptibility calculated from the experimental results.

关键词： Hot tearing Microstructure Magnesium alloys Casting Criterion

Investigation of the alloying effect on deformation behavior in Mg by Visco-Plastic Self-Consistent modeling

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Journal of Magnesium and Alloys 2020年第1期8卷 210-218页

作者： Alireza Maldar Leyun Wang Gaoming Zhu Xiaoqin ZENG National Engineering Research Center of Light Alloy Net Forming School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China The State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240China

Alloying elements can drastically alter the deformation behavior of Mg.In the present work,Visco-Plastic Self-Consistent(VPSC)modeling was employed to investigate the effect of alloying elements on Mg’s tensile behavior,in particular the relative activity of different slip and twinning modes.Mg-0.47 wt.%Ca,Mg-2 wt.%Nd,and AZ31 extruded alloys were deformed by micro-tensile tests in a scanning electron microscope(SEM).Texture and grain size measured by electron backscatter diffraction(EBSD)were used as the input for VPSC.After parameter optimization,the VPSC model successfully reproduced the stress-strain curve of each alloy.Simulation results indicate that the slip/twinning activity in the three alloys are different.Mg-0.47 wt.%Ca shows strong extrusion texture,and prismatic slip was quite active during its tensile deformation.In contrast,Mg-2 wt.%Nd shows weak extrusion texture,and basal slip was dominant.This alloy also developed more twinning activity than the other two alloys.AZ31 shows strong extrusion texture similar as Mg-0.47 wt.%Ca,but prismatic slip was less active in it.The slip/twinning activity revealed by the VPSC model can explain the difference in the tensile behavior of the three alloys.

关键词： Mg alloys Crystal plasticity Slip EBSD Tensile test

Hot compressive deformation behaviors of Mg–10Gd–3Y–0.5Zr alloy

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Progress in Natural Science:Materials International 2016年第1期26卷 78-84页

作者： Tingting Zheng Dejiang Li Xiaoqin ZENG Wenjiang Ding National Engineering Research Center of Light Alloy Net Forming School of Materials Science and Engineering Shanghai Jiao Tong University

In this paper, the hot compressive deformation characteristics of a Mg–10Gd–3Y–0.5Zr（GW103K） alloy have been investigated by isothermal compression test at the temperature range of 350–450°C and strain rate range of 0.0001–0.1s;. True stress–strain relationships at various strain rates showed the typical strain hardening and softening stage which is indicative of dynamic recrystallization during deformation. The results showed that the peak stress was obviously dependent on temperature and strain rate. A constitutive equation to describe the deformation process was established based on the hyperbolic sine function. The stress exponent n and apparent activation energy Q were determined to be 3.018 and 203.947 k J/mol, respectively. Microstructure investigation showed that dislocation slipping was the dominant deformation mechanism during the hot deformation at all conditions. However, at the temperatures lower than 400 °C and strain rates higher than 0.01 s;, twinning was observed to be activated, which indicated another deformation mechanism. Dynamic recrystallization and dynamic precipitation were found to occur simultaneously under such deformation condition.

关键词： Mg-RE alloys Hot deformation Dynamic precipitation Constitutive equation Microstructure evolution

Dispersal patterns in Yunnan snub-nosed monkeys

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Current Zoology 2022年第3期68卷 265-273页

作者： Wancai XIA Fan WANG Dali WANG Xiaoqin ZENG Chan YANG Ali KRZTON Baoping REN Dayong LI Key Laboratory of Southwest China Wildlife Resources Conservation(Ministry of Education) China West Normal UniversityNanchong CitySichuan 637009China Institute of Rare Animals and Plants China West Normal UniversityNanchong CitySichuan 637009China Auburn University Libraries Auburn UniversityAuburnAL 36849USA Key Laboratory for Ecology of Tropical Islands(Ministry of Education) Hainan Normal UniversityHaikouHainan 571158China Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province Hainan Normal UniversityHaikouHainan 571158China

Sex-biased dispersal is common in group-living animals.Due to differences in local demographic and environmental factors,sex-biased dispersal presents many irregular patterns.In this study,a habituated,individually identified Yunnan snub-nosed monkey Rhinopithecus bieti group was observed over 9 years;192 dispersal events,including 97 male dispersal events(25 natal dispersal and 72 secondary dispersal)and 95 female dispersal events(34 natal dispersal and 61 secondary dispersal)were observed.Males and females showed different dispersal paths,dispersal ages,and dispersal patterns.Females had 2 dispersal paths,whereas males had 4 paths.In terms of age of dispersal,the male age of natal dispersal was younger than for females.Males prefer single dispersal,whereas females prefer parallel dispersal.Our study indicates that the dispersal pattern of R.bieti should be classified as a bisexual dispersal pattern.The differences in dispersal path,average age at dispersal,and dispersal path pattern indicate that Yunnan snub-nosed monkeys may still retain a loose matrilineal social system.

关键词： bisexual dispersal dispersal parallel dispersal Rhinopithecus bieti

Grain-scale deformation in a Mg-0.8wt% Y alloy using crystal plasticity finite element method

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Journal of Materials Science & Technology 2019年第10期35卷 2200-2206页

作者： Wenxue Li Leyun Wang Bijin Zhou Chuanlai Liu Xiaoqin ZENG National Engineering Research Center of Light Alloy Net Forming School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai200240China The State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai200240China

Magnesium(Mg) alloys with hexagonal close-packed(HCP) structure usually have a poor ductility at room temperature. The addition of yttrium(Y) can improve the ductility of Mg alloys. To understand the underlying mechanism, crystal plasticity finite element method(CPFEM) was employed to simulate the tensile deformation of a Mg-0.8 wt% Y alloy. The simulated stress–strain curve and the grain-scale slip activities were compared with an in-situ tensile test conducted in a scanning electron microscope.According to the CPFEM result, basal slip is the dominant deformation mode in the plastic deformation stage, accounting for about 50% of total strain. Prismatic slip and pyramidal a slip are responsible for about 25% and 20% of the total strain, respectively. Pyramidal c + a slip and twinning, on the other hand,accommodate much less strain.

关键词： Crystal Plasticity finite element modeling EBSD Dislocation Mechanical Behavior

High-throughput calculations combining machine learning to investigate the corrosion properties of binary Mg alloys

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Journal of Magnesium and Alloys 2024年第4期12卷 1406-1418页

作者： Yaowei Wang Tian Xie Qingli Tang Mingxu Wang Tao Ying Hong Zhu Xiaoqin ZENG University of Michigan-Shanghai Jiao Tong University Joint Institute Shanghai Jiao Tong University200240ShanghaiChina State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai200240China

Magnesium(Mg)alloys have shown great prospects as both structural and biomedical materials,while poor corrosion resistance limits their further application.In this work,to avoid the time-consuming and laborious experiment trial,a high-throughput computational strategy based on first-principles calculations is designed for screening corrosion-resistant binary Mg alloy with intermetallics,from both the thermodynamic and kinetic perspectives.The stable binary Mg intermetallics with low equilibrium potential difference with respect to the Mg matrix are firstly identified.Then,the hydrogen adsorption energies on the surfaces of these Mg intermetallics are calculated,and the corrosion exchange current density is further calculated by a hydrogen evolution reaction(HER)kinetic model.Several intermetallics,e.g.Y_(3)Mg,Y_(2)Mg and La_(5)Mg,are identified to be promising intermetallics which might effectively hinder the cathodic HER.Furthermore,machine learning(ML)models are developed to predict Mg intermetallics with proper hydrogen adsorption energy employing work function(W_(f))and weighted first ionization energy(WFIE).The generalization of the ML models is tested on five new binary Mg intermetallics with the average root mean square error(RMSE)of 0.11 eV.This study not only predicts some promising binary Mg intermetallics which may suppress the galvanic corrosion,but also provides a high-throughput screening strategy and ML models for the design of corrosion-resistant alloy,which can be extended to ternary Mg alloys or other alloy systems.

关键词： Mg intermetallics Corrosion property High-throughput Density functional theory Machine learning

Dislocation behavior in a polycrystalline Mg-Y alloy using multi-scale characterization and VPSC simulation

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Journal of Materials Science & Technology 2022年第3期98卷 87-98页

作者： Bijin Zhou Leyun Wang Jinhui Wang Alireza Maldar Gaoming Zhu Hailong Jia Peipeng Jin Xiaoqin ZENG Yanjun Li National Engineering Research Center of Light Alloy Net Forming Shanghai Jiao Tong UniversityShanghai 200240China School of Mechanical Engineering Suzhou University of Science and TechnologySuzhou 215009China Department of Materials Science and Engineering Norwegian University of Science and TechnologyTrondheim 7491Norway School of Mechanical Engineering Qinghai UniversityXining 810016China Key Laboratory of Automobile Materials of Ministry of Education&School of Materials Science and Engineering Nanling CampusJilin UniversityChangchun 130025China State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240China

In this study,the dislocation behavior of a polycrystalline Mg-5Y alloy during tensile deformation was quantitatively studied by an in-situ tensile test,visco-plastic self-consistent(VPSC)modeling,and transmission electron microscopy(TEM).The results of the in-situ tensile test show thatdislocations contribute to most of the deformation,while a small fraction ofdislocations are also activated near grain boundaries(GBs).The critical resolved shear stresses(CRSSs)of different dislocation slip systems were estimated.The CRSS ratio between prismatic and basaldislocation slip in the Mg-Y alloy(~13)is lower than that of pure Mg(~80),which is considered as a major reason for the high ductility of the alloy.TEM study shows that thedislocations in the alloy have high mobility,which also helps to accommodate the deformation near GBs.

关键词： Mg-Y alloy Dislocation behavior Deformation mechanisms Critical resolved shear stress