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Effect of aging treatment on the precipitation transformation and age hardening of Mg-Gd-Y-Zn-Zr alloy

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Journal of Magnesium and Alloys 2023年第12期11卷 4628-4643页

作者： Mu Meng Honglei Zhang Zhi Gao Genxing Lei jianmin yu College of Materials Science and Engineering North University of ChinaXueyuan Road 3Taiyuan 030051China Beijing North Vehicle Group Corporation ZhuJiaFen 5th LiBeijing 100072China

In this study, the precipitation transformation and age hardening of solution-treated Mg-9Gd-4Y-2Zn-0.5Zr(wt.%) alloy were investigated at different aging treatment parameters. The precipitation sequences of the alloy aged at 200℃, 250℃ and 300℃ are β’’(DO19) → β’(BCO) → β(FCC), β’’(DO19) → β’(BCO) → β_(1)(FCC) → β(FCC) and β(FCC), respectively. The streaks sequences of the alloy aged at 200℃, 250℃ and 300℃ are SF, SF → 14H-LPSO and SF → 14H-LPSO, respectively. For the alloy aged at 200℃ and 250℃, the increase in hardness with increasing aging time is contributed from the increase in precipitate volume fraction and the transformation from β’’ to β’ phase with basal → prismatic and spherical → spindle-like precipitate changes. The decrease in hardness after the peak-aging stage is attributed to the appearance of micro-sized β precipitates. Because of the smaller size of precipitates and the triangular arrangement of β’ precipitate, the hardness of the alloy aged at 200℃ is higher than that aged at 250℃. For the alloy aged at 300℃, the appearance of only micro-sized β precipitate and its coarsening with increasing aging time leads to the lowest hardness and an overall decrease in hardness with the aging time.

关键词： Mg-Gd-Y-Zn-Zr alloy Aging treatment Precipitation transformation Age hardening

Recent research and development on forming for large magnesium alloy components with high mechanical properties

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Journal of Magnesium and Alloys 2023年第11期11卷 4054-4081页

作者： Zhimin Zhang jianmin yu Yong Xue Beibei Dong Xi Zhao Qiang Wang College of Materials Science and Engineering North University of China3 Xueyuan RoadTaiyuan 030051China

The lightweight of high-end equipment relies on high mechanical properties magnesium(Mg) alloy structural components, because it is the best way to improve equipment service performance and reduce energy consumption. This article summarizes the current progress and characteristics of large-scale high-performance Mg alloy components by analyzing the strengthening-toughening mechanisms, characteristics of plastic forming, and the preparation of large high mechanical properties forging blanks. Due to the lack of breakthroughs in the key technologies for forming large-scale Mg alloy components, their uniformity of mechanical properties and consistency are poor, the forming accuracy of components is low, and the production cost is high, which limit their engineering application and restrict the lightweight level of high-end equipment. In view of the above problems, the forming trends and research directions of large-scale and high mechanical properties Mg alloy components are proposed in this paper. It can provide help for the breakthrough of the key technology of large-scale Mg alloy components with high mechanical properties and expand the application of Mg alloy in high-end products.

关键词： Mg alloys Wrought Mg alloys components Plastic forming Large-scale Mg alloys components High mechanical properties

Effect of circumferential strain rate on dynamic recrystallization and texture of Mg-13Gd-4Y-2Zn-0.5Zr alloy during rotary backward extrusion

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Journal of Magnesium and Alloys 2020年第4期8卷 1228-1237页

作者： Yingze Meng jianmin yu Guanshi Zhang Yaojin Wu Zhimin Zhang Zheng Shi College of Mechanical and Electrical Engineering North University of ChinaTaiyuan 030051China College of Materials Science and Engineering North University of Chinaxueyuan road 3TaiyuanShanxiTaiyuan 030051China

Gleeble-3500 thermal simulator was applied to realize the rotary backward extrusion forming of Mg-13Gd-4Y-2Zn-0.5Zr(wt%)alloy at different circumferential strain rate from 0.009 s^(-1)to 0.027 s^(-1)at 400℃and the dynamic recrystallization mechanism and texture evolution were *** results show that the grain size of the alloy was obviously refined after rotary backward *** the circumferenlial strain rate increased,the dynamic recrystallization fraction gradually increased causing the grain size decreased and the distribution of microstructure became more *** the same time,the texture of{0001},{10-10},{11-20}was weakened and the grain orientation distribution became more *** the increase of circumferential strain rate,the discontinuous dynamic recrystallization mechanism became dominant,which promoted the weakening of texture and grain refinement of the alloy.

关键词： Mg-Gd-Y-Zn-Zr alloy Rotary backward extrusion Dynamic recrystallization Texture

Serum thioredoxin activity:a promising biomarker for assessment of coronary stenosis severity in patients with coronary artery disease

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Science Bulletin 2017年第11期62卷 752-754页

作者： Jinling Li Pei Wang Li Xiao jianmin yu Xianrui Kong Liangwei Zhong Medical School University of Chinese Academy of Sciences Beijing Key Laboratory of Immunology Regulation and Organ Transplantation Basic Research Laboratory of Organ Transplant Institutethe 309th Hospital of the People's Liberation Army

Coronary artery disease(CAD)is one of the major death causes *** methods may improve the progress of ***,specific biomarkers are required for detecting coronary stenosis severity and monitoring *** spiral computed tom... 详细信息

关键词：动脉狭窄冠心病生物标记物蛋白活性冠状动脉造影冠状动脉疾病患者评价

Influence of strain rate on grain refinement and texture evolution under complex shear stress conditions

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Journal of Magnesium and Alloys 2023年第7期11卷 2558-2584页

作者： Zhaocan Li Guoqin Wu jianmin yu Jiebing Wang Jingjing Han Huiyong Cui Zhimin Zhang College of Materials Science and Engineering North University of China3 Xueyuan RoadTaiyuan 030051China Science and Technology on Space Physics Laboratory China Academy of Launch Vehicle TechnologyBeijing 100076China

The effects of different complex shear stress conditions on grain refinement and texture evolution of Mg-13Gd-4Y-2Zn-0.5Zr alloy were *** increasing strain rate,the average grain size of compression-shear(CS)and compression-torsion(CT)samples are decreased,and the grain size of dynamic recrystallization(DRX)grains is also *** is because that the precipitation number ofβphases is increased,and the hindering effect on grain growth can be significantly *** DRX fractions of CS and CT samples are decreased with increased strain *** low DRX fraction at high strain rate is related to the insufficient time for grains to *** DRX process can be promoted by the PSN mechanism of second phases,and the grain growth can be restricted by the pinning *** the same time,the texture strength is enhanced as the strain rate ***,the kinking degree of lamellar long-period stacking ordered(LPSO)phases is *** complex shear stress conditions,non-basal slip,especially pyramidal slip,is easily activated and the texture is deflected *** with the CS samples,CT samples have smaller average grain size,higher DRX fraction,and lower texture strength for a certain strain *** is because that the equivalent stress of the CT sample is larger,the stress triaxiality is smaller,so more serious dislocations are piled up near grain boundaries and second *** the same time,since CT sample was sheared with torsion,the dislocation movement path can be called“rotational dislocation accumulation”,and the longer distribution path of the CT sample is generated,so more sub-grains and low-angle grain boundaries(LAGBs)are *** with the CS sample,more huge-angle grain boundaries(HAGBs)and DRX grains are formed from grain boundary to grain interior,so better grain refinement effect is achieved.

关键词： Simple shear Compression-shear Compression-torsion Grain refinement Texture evolution ASB

Durable hierarchical phosphorus‐doped biphase MoS_(2)electrocatalysts with enhanced H^(*)adsorption

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Carbon Energy 2024年第4期6卷 104-114页

作者： Yongteng Qian jianmin yu Zhiyi Lyu Qianwen Zhang Tae Hyeong Lee Huan Pang Dae Joon Kang College of Pharmacy Jinhua PolytechnicJinhuaZhejiangChina Department of Physics Sungkyunkwan UniversitySuwonGyeonggi‐doRepublic of Korea International Collaborative Laboratory of 2D Materials for Optoelectronic Science and Technology of Ministry of Education Institute of Microscale OptoelectronicsShenzhen UniversityShenzhenGuangdongChina School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhouJiangsuChina

Phase engineering is an efficient strategy for enhancing the kinetics of electrocatalytic ***,phase engineering was employed to prepare high‐performance phosphorous‐doped biphase(1T/2H)MoS_(2)(P‐BMS)nanoflakes for hydrogen evolution reaction(HER).The doping of MoS_(2)with P atoms modifies its electronic structure and optimizes its electrocatalytic reaction kinetics,which significantly enhances its electrical conductivity and structural stability,which are verified by various characterization tools,including X‐ray photoelectron spectroscopy,high‐resolution transmission electron microscopy,X‐ray absorption near‐edge spectroscopy,and extended X‐ray absorption fine ***,the hierarchically formed flakes of P‐BMS provide numerous catalytic surface‐active sites,which remarkably enhance its HER *** optimized P‐BMS electrocatalysts exhibit low overpotentials(60 and 72 mV at 10 mA cm^(−2))in H_(2)SO_(4)(0.5 M)and KOH(1.0 M),*** mechanism of improving the HER activity of the material was systematically studied using density functional theory calculations and various electrochemical characterization *** study has shown that phase engineering is a promising strategy for enhancing the H*adsorption of metal sulfides.

关键词： 1T/2H MoS_(2) density functional theory electrocatalysts phase engineering phosphorous doping

Grain refinement impact on the mechanical properties and wear behavior of Mg-9Gd-3Y-2Zn-0.5Zr alloy after decreasing temperature reciprocating upsetting-extrusion

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Journal of Magnesium and Alloys 2022年第12期10卷 3506-3519页

作者： Wenlong Xu jianmin yu Leichen Jia Chang Gao Zhan Miao Guoqin Wu Guojun Li Zhimin Zhang School of Material Science and Engineering North University of ChinaTaiyuan 030051China

Based on the deforming technique of severe plastic deformation(SPD), the grain refinement of a Mg-9Gd-3Y-2Zn-0.5Zr alloy treated with decreasing temperature reciprocating upsetting-extrusion(RUE) and its influence on the mechanical properties and wear behavior of the alloy were studied. The RUE process was carried out for 4 passes in total, starting at 0 ℃ and decreasing by 10 ℃ for each pass. The results showed that as the number of RUE passes increased, the grain refinement effect was obvious, and the second phase in the alloy was evenly distributed. Room temperature tensile properties of the alloy and the deepening of the RUE degree showed a positive correlation trend, which was due to the grain refinement, uniform distribution of the second phase and texture weakening. And the microhardness of the alloy showed that the microhardness of RUE is the largest in 2 passes. The change in microhardness was the result of dynamic competition between the softening effect of DRX and the work hardening effect. In addition, the wear resistance of the alloy showed a positive correlation with the degree of RUE under low load conditions. When the applied load was higher, the wear resistance of the alloy treated with RUE decreased compared to the initial state alloy. This phenomenon was mainly due to the presence of oxidative wear on the surface of the alloy, which could balance the positive contribution of severe plastic deformation to wear resistance to a certain extent.

关键词： Mg-9Gd-3Y-2Zn-0.5Zr alloy Reciprocating upsetting-extrusion Grain refinement Texture Mechanical properties Wear behavior

Study on the Leaching of Pt, Pd and Rh from Spent Auto-catalysts in Various Acidities

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贵金属 2012年第A01期33卷 28-32页

作者： WAN Jing yu jianmin QIAN Lin WAN Huoyin ZHAO yunkun Kunming Sino-Platinum Metals Catalyst Co.Ltd. Kunming 650106 State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Platinum Metals Kunming Institute of Precious MetalsKunming 650106China

Auto-catalysts were the largest consumers of platinum group metals and the most important secondary resources, recovery of PGMs from spent auto-catalysts by leaching with various acidities were investigated. The leaching thermodynamics of PGMs at 363 K was first discussed. At 363 K the higher the acidities of HCl, the higher the leaching recoveries of PGMs, and the sequence of leaching recovery was Pd>Pt>Rh. When H2SO4 used alone, the leaching recoveries of PGMs was low, when the acidity of H2SO4 increasing, the leaching recovery of Rh kept stable.

关键词： spent auto-catalysts platinum group metals (PGMs) leaching acidity

Generating highly active oxide-phosphide heterostructure through interfacial engineering to break the energy scaling relation toward urea-assisted natural seawater electrolysis

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Journal of Energy Chemistry 2024年第10期97卷 687-699,I0014页

作者： Ngoc Quang Tran Nam Hoang Vu jianmin yu Khanh Vy Pham Nguyen Thuy Tien Nguyen Tran Thuy-Kieu Truong Lishan Peng Thi Anh Le Yoshiyuki Kawazoe Center for Innovative Materials and Architectures Ho Chi Minh City 700000Vietnam Vietnam National University Ho Chi Minh City 700000Vietnam Faculty of Materials Science and Technology University of ScienceHo Chi Minh City 700000Vietnam Department of Mechanical Engineering Hanbat National University(HBNU)Daejeon 34158Republic of Korea Key Laboratory of Rare Earths Ganjiang Innovation AcademyChinese Academy of SciencesGanzhou 341119JiangxiChina School of Chemical Engineering-Hanoi University of Science and Technology Hanoi 10000Vietnam New Industry Creation Hatchery Center Tohoku UniversitySendai 980-8579Japan

Urea-assisted natural seawater electrolysis is an emerging technology that is effective for grid-scale carbon-neutral hydrogen mass production yet *** scaling relations is an effective strategy to break through the bottleneck of natural seawater ***,by DFT calculation,we demonstrated that the interface boundaries between Ni_(2)P and MoO_(2) play an essential role in the selfrelaxation of the Ni-O interfacial bond,effectively modulating a coordination number of intermediates to control independently their adsorption-free energy,thus circumventing the adsorption-energy scaling *** this conceptual model,a well-defined 3D F-doped Ni_(2)P-MoO_(2) heterostructure microrod array was rationally designed via an interfacial engineering strategy toward urea-assisted natural seawater *** a result,the F-Ni_(2)P-MoO_(2) exhibits eminently active and durable bifunctional catalysts for both HER and OER in acid,alkaline,and alkaline sea water-based *** in-situ analysis,we found that a thin amorphous layer of NiOOH,which is evolved from the Ni_(2)P during anodic reaction,is real catalytic active sites for the OER and UOR ***,such electrode-assembled urea-assisted natural seawater electrolyzer requires low voltages of 1.29 and 1.75 V to drive 10 and600 mA cm^(-2)and demonstrates superior durability by operating continuously for 100 h at 100 mA cm^(-2),beyond commercial Pt/C||RuO_(2) and most previous reports.

关键词： Interfacial engineering Break scaling relationships Doping Natural seawater splitting Urea electrolysis