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Bimodal grain structure formation and strengthening mechanisms in Mg-Mn-Al-Ca extrusion alloys

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Journal of Magnesium and Alloys 2023年第12期11卷 4407-4419页

作者： Jianyue Zhang Peng Peng Qingshan Yang Alan A.Luo Department of Materials Science and Engineering The Ohio State UniversityColumbusOH 43210USA School of Metallurgy and Material Engineering Chongqing University of Science and TechnologyChongqing401331China Department of Integrated Systems Engineering The Ohio State UniversityColumbusOhio 43210USA

The effects of small additions of calcium (0.1%and 0.5%~1) on the dynamic recrystallization behavior and mechanical properties of asextruded Mg-1Mn-0.5Al alloys were investigated.Calcium microalloying led to the formation of Al_(2)Ca in as-cast Mg-1Mn-0.5Al-0.1Ca alloy and both Mg_(2)Ca and Al_(2)Ca phases in Mg-1Mn-0.5Al-0.5Ca alloy.The formed Al_(2)Ca particles were fractured during extrusion process and distributed at grain boundary along extrusion direction (ED).The Mg_(2)Ca phase was dynamically precipitated during extrusion process,hindering dislocation movement and reducing dislocation accumulation in low angle grain boundaries (LAGBs) and hindering the transformation of high density of LAGBs into high angle grain boundaries (HAGBs).Therefore,a bimodal structure composed of fine dynamically recrystallized (DRXed) grains and coarse un DRXed regions was formed in Ca-microalloyed Mg-1Mn-0.5Al alloys.The bimodal structure resulted in effective hetero-deformation-induced (HDI) strengthening.Additionally,the fine grains in DRXed regions and the coarse grains in un DRXed regions and the dynamically precipitated Mg_(2)Ca phase significantly enhanced the tensile yield strength from 224 MPa in Mg-1Mn-0.5Al to335 MPa and 352 MPa in Mg-1Mn-0.5Al-0.1Ca and Mg-1Mn-0.5Al-0.5Ca,respectively.Finally,a yield point phenomenon was observed in as-extruded Mg-1Mn-0.5Al-x Ca alloys,more profound with 0.5%Ca addition,which was due to the formation of (■) extension twins in un DRXed regions.

关键词： Magnesium alloys Extrusion Dynamic precipitation Dynamic recrystallization Bimodal grain structure Mechanical properties

The effects of orientation control via tension-compression on microstructural evolution and mechanical behavior of AZ31 Mg alloy sheet

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Journal of Magnesium and Alloys 2022年第2期10卷 446-458页

作者： Qingshan Yang Bin Jiang Bo Song Zujian Yu Dewei He Yanfu Chai Jianyue Zhang Fusheng Pan School of Metallurgy and Material Engineering Chongqing University of Science and TechnologyChongqing 401331China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China School of Materials and Energy Southwest UniversityChongqing400715China MagIC–Magnesium Innovation Centre Helmholtz-Zentrum GeesthachtMax-Planck-Straße 1Geesthacht 21502Germany School of Engineering Technology Purdue UniversityWest LafayetteIN 47907-2021United States

The grain orientation control via twinning activity on deformation features is of great significance to offer a key insight into understanding the deformation mechanism of Mg alloy sheets.The{10–12}twinning were performed by pre-strain paths,i.e.,tension(6%)and compression(5%)perpendicular to the c-axis along extrusion direction(ED),to investigate the microstructural evolution and mechanical properties of AZ31 Mg alloy sheets.The distinction in the texture evolution and strain hardening behavior was illustrated in connection with the pre-strain paths for the activities of twinning and slip.The result shows that the activation of the deformation mode was closely bound up with the grain orientation and the additional applied load direction.The{10–12}twin-texture components with c-axis//ED were generated by precompression,which can provide an appropriate alternative to accommodate the thin sheet thickness strain and enhance the room temperature formability of Mg alloy sheet.

关键词： Mg alloy Orientation control Microstructural evolution Texture Stretch formability

The tribological behavior of a surface-nanocrystallized magnesium alloy AZ31 sheet after ultrasonic shot peening treatment

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Journal of Magnesium and Alloys 2021年第4期9卷 1190-1203页

作者： Jianyue Zhang Yongxin Jian Xuzhe Zhao Dean Meng Fusheng Pan Qingyou Han School of Engineering Technology Purdue UniversityWest LafayetteIN 47906USA State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049PR China Böllhoff Inc TroyMI 48084USA School of Automobile Chang’an UniversityXi’an 710064PR China College of Materials Science and Engineering Chongqing UniversityChongqing 400045PR China

A magnesium alloy AZ31 sheet was processed by ultrasonic shot peening treatment to fabricate a surface nanocrystalline,and a ball-on-disk dry sliding wear test was performed to evaluate the tribological behavior after treatment.The microstructure observation indicated a gradient nanocrystalline structure was formed after USSP treatment.The microhardness at the top surface was improved from 60 HV to 145 HV after treatment.The formed nanocrystalline resulted in an easy formation of MgO patches on the surface and reduced the coefficient of friction.Moreover,the formed nanocrystalline leaded to a retard of delamination with increasing the sliding speed and applied load,which was due to its stronger sub-surface.Under high sliding speed(0.5 m/s)and high applied load(50 N),it was firstly found that the formed nanocrystalline prevented the happening of thermal softening and melting.The possible reasons accounting for the prevention of thennal softening and melting were discussed accordingly.

关键词： AZ31Mg alloy Ultrasonic shot peening Surface-nanocrystallization Wear mechanism

Mechanical behavior and microstructure evolution for extruded AZ31 sheet under side direction strain

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Progress in Natural Science:Materials International 2020年第2期30卷 270-277页

作者： Qingshan Yang Bin Jiang Bo Song Daliang Yu Sensen Chai Jianyue Zhang Fusheng Pan School of Metallurgy and Material Engineering Chongqing University of Science and Technology National Engineering Research Center for Magnesium Alloys Chongqing University School of Materials and Energy Southwest University School of Engineering Technology Purdue University

AZ31 magnesium alloy sheets were prepared by a conventional extrusion(CE) and a novel integrated extrusion with side direction strain(SE).The microstructure characterizations,crystallographic texture and mechanical property tests were carried out and compared between the extruded Mg alloy sheets processed by CE and SE.The results indicated that the SE sheets exhibited an excellent combination of strength and ductility.To reveal the side strain effect,the finite element model was employed to investigate the effective stress and strain behavior of the AZ31 magnesium alloy sheets during CE and SE processes.It was found that the SE process was effective in weakening the stress and strain concentration.This implied that it developed an additional side direction strain through the sheet thickness during the hot extrusion.Meanwhile,the side strain shear paths could promote the local accumulation of dynamically recrystallized grains and increase the random high-angle boundaries to achieve weak(0002) basal texture.Important factors including the side strain path and extrusion parameters need to be taken into account to understand the deformation mechanism and microstructure evolution.

关键词： AZ31 Mg alloy Microstructure Texture Extrusion Side direction strain

Twinning, grain orientation, and texture variations in Mg alloy processed by pre-rolling

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Progress in Natural Science:Materials International 2019年第2期29卷 231-236页

作者： Qingshan Yang Qingwei Dai Chao Lou Jiahong Dai Jianyue Zhang Bin Jiang Fusheng Pan School of Metallurgy and Material Engineering Chongqing University of Science and Technology National Engineering Research Center for Magnesium Alloys Chongqing University National and Local Joint Engineering Laboratory of Traffic Civil Engineering Materials Chongqing Jiaotong University College of Materials Science and Engineering Yangtze Normal University School of Engineering Technology Purdue University

A pre-rolling(PR) process with a small pre-strain was applied along the transverse direction(TD) and the extrusion direction(ED) of non-basal and basal textured AZ61 Mg alloys at room temperature to investigate the induced twinning behavior. The microstructural evolution of the alloys was used to evaluate the grain-boundary effect in terms of the texture variation. The results demonstrated that■ extension twinning was introduced by the PR process and that the volume fraction of twins increased with increasing thickness reduction. The subdivision of grains via twinning induced grain reorientation that generated a prominent basal texture with the c-axis parallel to the normal direction(ND) after PR. The textured Mg alloy with this c-axis//TD feature can promote twinning activity. The twinning performance was critical to initiate plastic deformation, therefore to determine deformation behavior at room temperature. The deformation mechanism was also addressed related to the extension twin lamellae.

关键词： Mg alloy Twin Grain orientation Texture

Accurate and explainable machine learning for the power factors of diamond-like thermoelectric materials

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Journal of Materiomics 2022年第3期8卷 633-639页

作者： Zhe Yang Ye Sheng Cong Zhu jianyue Ni Zhenyu Zhu Jinyang Xi Wu zhang Jiong Yang Materials Genome Institute Shanghai UniversityShanghai200444China School of Computer Engineering and Science Shanghai UniversityShanghai200444China School of Mechanics and Engineering Science Shanghai UniversityShanghai200444China

The application of machine learning(ML)-based methods to the study of thermoelectric(TE)materials is promising.Although conventional ML algorithms can achieve high prediction performance,their lack of interpretability severely obstructs researchers from extracting material-oriented insights from ML models.In this work,high ML-based prediction performance was achieved with respect to TE power factors(PFs),and the results were well understood by the SHapley Additive exPlanations(SHAP),a method to identify the correlations between targets and descriptors.We designed a robust PF prediction model for diamond-like compounds via a stacking technique,and the model achieved a coefficient of determination value above 0.95 on the test set.From the SHAP analysis,the PFs were negatively correlated with electronegativity and positively correlated with the descriptor“volume per atom”based on the previously reported dataset.TE domain knowledge was adopted to understand these correlations.This work shows that ML models can achieve high accuracy while exhibiting good interpretability,making them useful for materials scientists.

关键词： Machine learning Thermoelectric materials Interpretability Power factor

Real-time video compression system design and hardware implementation based on multiple ADV212

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High Technology Letters 2016年第3期22卷 282-287页

作者：徐冬冬 Wang Wenhua zhang Yu zhang Xingxiang Fu Tianjiao Ren jianyue Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Scienses Changchun 130033 P. R. China University of Chinese Academy of Sciences Beijing 100039 P. R. China

In order to improve the transmission rate of the compression system,a real-time video lossy compression system based on multiple ADV212 is proposed and achieved. Considering the CMOS video format and the working principle of ADV212,a Custom-specific mode is used for various video formats firstly. The data can be cached through the FPGA internal RAM and SDRAM Ping-Pong operation. And the working efficiency is greatly promoted. Secondly,this method can realize direct code stream transmission or do it after storage. Through the error correcting coding,the correction ability of the flash memory is highly improved. Lastly,the compression and de-compression circuit boards are involved to specify the performance of the method. The results show that the compression system has a real-time and stable performance. And the compression ratio can be changed arbitrarily by configuring the program. The compression system can be realized and the real-time performance is good with large amount of data.

关键词： compression system ADV212 Custom-specific Ping-Pong operation error correction coding

Magnesium research and applications: Past, present and future

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Journal of Magnesium and Alloys 2023年第11期11卷 3867-3895页

作者： Jianyue Zhang Jiashi Miao Nagasivamuni Balasubramani Dae Hyun Cho Thomas Avey Chia-Yu Chang Alan A.Luo Department of Materials Science and Engineering The Ohio State UniversityColumbusOH 43210USA Department of Integrated Systems Engineering The Ohio State UniversityColumbusOH 43210USA

As the lightest structural metal and one of the most abundant metallic elements on earth, magnesium(Mg) has been used as an "industrial metal" for lightweighting in the transportation and electronics industries, in addition to other traditional applications in aluminum alloying,steel desulfurization and protective anodes. In recent years, research has shown significant potential for Mg to become a "technology metal"in a variety of new applications from energy storage/battery to biomedical products. However, global Mg production has shown steady but moderate growth in the last three decades. Mg applications as an industry metal are still limited due to some sustainability concerns of primary Mg production, as well as a number of technical issues related to the structural and corrosion performance of commercial Mg alloys.New Mg applications as an industrial or technology metal face tremendous technical challenges, which have been reflected in the intensified global research efforts in the last twenty years. This paper will review some past and present applications, and discuss future opportunities and challenges for Mg research and applications for the global Mg community.

关键词： Magnesium alloys Structural applications Lightweighting Biomedical applications Energy applications

中国海水养殖产业绿色全要素生产率分解及影响因素分析

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科技管理研究 2022年第3期42卷 206-213页

作者：张懿纪建悦青岛理工大学商学院山东青岛266520 中国海洋大学经济学院山东青岛266100 中国海洋大学海洋发展研究院山东青岛266100

采用2008—2017年中国沿海10个省份的数据,通过SBM-GML模型对海水养殖绿色全要素生产率进行测度,从纯技术效率变化、规模技术效率变化、纯技术变化和规模技术变化4个方面进行分解,并通过FGLS模型系统地研究其影响因素。结果表明,我国海... 详细信息

采用2008—2017年中国沿海10个省份的数据,通过SBM-GML模型对海水养殖绿色全要素生产率进行测度,从纯技术效率变化、规模技术效率变化、纯技术变化和规模技术变化4个方面进行分解,并通过FGLS模型系统地研究其影响因素。结果表明,我国海水养殖业绿色全要素生产率呈上升趋势,主要由纯技术变化驱动,规模技术效率变化和规模技术变化的促进作用较小,纯技术效率变化具有抑制作用;海洋环境规制与绿色全要素生产率显著负相关,海洋科教投入、渔民培训强度、技术推广强度促进了绿色全要素生产率的提升,海水养殖产业发展和渔业开放程度的影响并不显著。

关键词：海水养殖产业非期望产出绿色全要素生产率 SBM-GML指数