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plastic deformation and heat treatment of Mg-Li alloys:a review

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Journal of Materials Science & Technology 2022年第4期99卷 193-206页

作者： Xiang Peng Wencai Liu Guohua Wu Hao Ji Wenjiang Ding National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composite School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China

As the lightest structural metallic materials,Mg-Li alloys have a bright development prospect in the fields of aerospace,weapon equipment,electronic technology and transportation.In this paper,the research progress of deformation processing and heat treatment of Mg-Li alloys is reviewed,with particular emphasis on the factors affecting the plastic deformation,the effects of plastic deformation on microstructural evolution and mechanical properties,and the heat treatment behavior of Mg-Li alloys.The problems existing in the scale application of Mg-Li alloys are pointed out,and the research focus of Mg-Li alloys in the future are also prospected.

关键词： Mg-Li alloy plastic deformation Heat treatment Aging softening Research progress

plastic deformation of magnesium alloy with different forming parameters during ultrasonic vibration-assisted single-point incremental forming

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Rare Metals 2022年第11期41卷 3878-3886页

作者： Chun Jian Su Ting Ting Xu Ke Zhang Ke Zhang Shu Mei Lou Qing Wang College of Mechanical and Electronic Engineering Shandong University of Science and TechnologyQingdao266590China

The research of forming parameters on the ultrasonic vibration single-point incremental forming of magnesium alloy plastic deformation can provide a theoretical basis for the establishment of the forming parameters.According to the forming characteristics of magnesium alloy sheet,a new method of ultrasonic vibration-as sis ted single-point incremental forming was proposed.The influence of forming parameters on the plastic deformation of magnesium alloy was studied by finite element simulation and experimentation.The influence of vibration frequency,amplitude,friction coefficient,and tool head size on stress and thinning rate of magnesium alloy during ultrasonic vibration-as sis ted single-point asymptotic forming was studied.The results show that the vibration frequency of 20 kHz and forming tool radius of about 5 mm are beneficial for plastic deformation magnesium alloy in ultrasonic vibration-assisted single-point incremental forming.With vibration amplitude increasing,the maximum shear stress tends to decrease as a whole,but at the amplitude of 0.16 mm,the thinning rate is large and fracture occurs easily.With friction coefficient increasing,the maximum shear stress tends to increase,and there is a good linear relationship between the maximum thinning rate and the friction coefficient.

关键词： Magnesium alloy Ultrasonic vibration Incremental forming Forming parameters plastic deformation

Analytical Solution of Thermo-Elastic-plastic deformation of the Combined Forging Die

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Journal of Shanghai Jiaotong university(Science) 2023年第2期28卷 280-288页

作者：曹民业苗宏量胡成亮赵震 Institute of Forming Technology&Equipment School of Materials Science and EngineeringNational Engineering Research Center of Die and Mold CADShanghai Jiao Tong UniversityShanghai 200030China

On the multi-layer forging die used in daily life,stressed ring can strength the die structure within elastic deformation and the die material can be self-strengthened through uniform plastic deformation by autofrettage effect,whereas the thermal effect generated during forging process can directly influence the stress state and dimension of the forging die in service.In this study,an analytical solution of the thermo-elastic-plastic deformation in the forging die is derived.The relationships between the radial and circumferential stresses and the temperature distribution,which are directly related to geometric parameters,material properties and working pressure,are determined.This helps to better understand the thermo-elastic-plastic deformation behavior of the die and design the combined forging die to achieve long service life and high accuracy product.

关键词： thermal deformation elastic deformation plastic deformation die temperature

plastic deformation Mechanism in Double-Roller Clamping Spinning of Flanged Thin-Walled Cylinder

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Chinese Journal of Mechanical Engineering 2018年第3期31卷 76-84页

作者： Shu-Qin Fan Sheng-Dun Zhao Chao Chen School of Mechanical Engineering Xi’an Jiaotong University

Double?roller clamping spinning(DRCS) is a new process for forming a thin?walled cylinder with a complex surface flange. The process requires a small spinning force,and can visibly improve forming quality and production e ciency. However,the deformation mechanism of the process has not been completely understood. Therefore,both a finite element numerical simulation and experimental research on the DRCS process are carried out. The results show that both radial force and axial force dominate the forming process of DRCS. The deformation area elongates along the radial direction and bends along the axial direction under the action of the two forces. Both the outer edge and round corner of the flange show the tangential tensile stress and radial compressive stress. The middle region shows tensile tangential stress and radial stress,while the inner edge shows compressive tangential stress and radial stress. Tan?gential tensile strain causes a wall thickness reduction in the outer edge and middle regions of the flange. The large compressive thickness strain causes material accumulation and thus,an increase in the wall thickness of the round corner. Because of bending deformation,the round corner shows a large radial tensile strain in addition. The inner edge of the flange shows small radial compressive strain and tensile strain in thickness. Thus,the wall thickness on the inner edge of the flange continues to increase,although the increment is small. Furthermore,microstructure analysis and tensile test results show that the flanged thin?walled cylinder formed by DRCS has good mechanical properties. The results provide instructions for the application of the DRCS process.

关键词： Flange Double?roller clamping spinning plastic deformation Cylinder

plastic deformation of Fine-Grained Al-Cu-Fe-（B） Icosahedral Poly-Quasicrystals at Elevated Temperature

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Chinese Physics Letters 2007年第8期24卷 2331-2334页

作者：王建波马家艳路璐熊冬霞 Key Laboratory of Acoustic and Photonic Materials and Devices of Ministry of Education and Department of Physics Wuhan University Wuhan 430072 Center for Electron Microscopy Wuhan University Wuhan 430072

Fine-grained Al-Cu-Fe-（B） icosahedral poly-quasicrystals （1QCs） as the main materials and fine-grained Al- Pd-Mn IQCs as the supplements, both prepared by powder metallurgy, are uniaxially deformed at vaNous temperatures and strain rates. The systematic study shows the dependences of curves of the true stress versus true strain on several parameters, such as temperature, strain rate and grain size. For Al-Cu-Fe IQCs with grain sizes of about 10-30μm, QC-specific intra-granular softening drop appears in the deformation curves at lower temperatures and/or faster strain rates, but disappears in those curves at higher temperatures and/or slower strain rates, which suggests that the inter-granular effects such as grain-boundary sliding should be taken into account to interpret the continuous hardening, similarly to conventional poly-crystals. For Al-Cu-Fe-B IQCs with smaller grain sizes of about 1 μm and fine-grained AI-Pd-Mn IQCs with grain sizes of about 10μm, QC- specific intra-granular softening drop is absent for all the deformation curves at the possible lowest temperature and fastest strain rate. This implies that the sma/ler the grain size, the more the inter-granular contribution. At the same time, due to the rapid recovery caused by intense diffusion in small-sized grains, the intra-granular quasicrystal lattice reorders rapidly from disordering, which also inhibits the intra-granular softening drop to some extent.

关键词： plastic deformation Fine-Grained Al--Cu--Fe--(B)

plastic deformation Mechanism of Dual-phase Steel at Different Strain Rates

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Journal of Wuhan University of Technology(Materials Science) 2020年第6期35卷 1142-1148页

作者：庞启航 ZHAO Zhenduo 徐梅徐振 ZHAO Tan School of Materials and Metallurgy University of Science and Technology LiaoningAnshan 114051China State Key Laboratory of Metal Material for Marine Equipment and Application Anshan Iron&Steel Group Co.Ltd.Anshan 114009China State Key Laboratory of Advanced Stainless Steel Materials Taiyuan Iron&Steel Group Co.Ltd.Taiyuan 030003China

The mechanical properties of dual-phase steel (DP1000) over the strain rate range of 10^-3-10^3 s^-1 were studied using an electronic universal testing machine and a high-speed tensile testing machine.The plastic deformation mechanism was investigated from the perspectives of the strain rate sensitivity index,activation volume and dynamic factors.The results show that the tensile strength and yield strength of DP1000 increase as the strain rate increases.The elongation increases without any change after fracture,and then decreased rapidly when the strain rate reaches 103 s^-1.The true strain curves of DP1000 show three stages:the point of instability decreases in the strain range of 10^-3-10^-1 s^-1;the instability point increases between 100-5×10^2 s^-1;above 5×10^2 s^-1,and the instability strain becomes smaller again.The plastic deformation mechanism of the DP was determined by the competitive contributions of work hardening (strain hardening,strain rate hardening) and softening effects due to the adiabatic temperature rise.

关键词： dual-phase steel strain rate plastic deformation microstructure

Research on deformation mechanism of AZ31 magnesium alloy sheet with non-basal texture during uniaxial tension at room temperature:A visco-plastic self-consistent analysis

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Journal of Magnesium and Alloys 2022年第7期10卷 1994-2008页

作者： Li Hu Huyuan Lv Laixin Shi Yu Chen Qiang Chen Tao Zhou Mingao Li Mingbo Yang College of Material Science and Engineering Chongqing University of TechnologyChongqing 400054China Southwest Technology and Engineering Research Institute Chongqing 400039China

The relationship between activities of involved deformation mechanisms and the evolution of microstructure and texture during uniaxial tension of AZ31 magnesium alloy with a rare non-basal texture has been thoroughly investigated in the present study by means of electron backscattered diffraction(EBSD) measurement and visco-plastic self-consistent(VPSC) modeling. These results show that except basal slip and prismatic slip, {10■2} extension twin(ET) also plays a significant role during plastic deformation. With the increasing tilted angle between loading direction and rolling direction(RD) of sheet, the activity of {10■2} ET possesses a decreasing tendency and its role in plastic deformation changes from the one mainly sustaining plastic strain to the one mainly accommodating local strain between individual grains. When {10■2} ET serves as a carrier of plastic strain, it mainly results in the formation of basal texture component(c-axis//ND, normal direction). By comparison, when the role of {10■2} ET is to accommodate local strain, it mainly brings about the formation of prismatic texture component(c-axis//TD, transverse direction). At large plastic deformation, the competition between basal slip and pyramidal slip is responsible for the concentration of tilted basal poles towards ND within all deformed samples. The larger difference is between the activities of basal slip and pyramidal slip, the smaller separation is between these two tilted basal poles. Besides,VPSC modeling overesttmates volume fractions of {10■2} ET in samples with angle of 0 to 30° between loading direction and RD of sheet because interactions between twin variants are not included in VPSC modeling procedure at the present form. In addition, as compatible deformation between individual grains cannot be considered in VPSC modeling, the predicted volume fractions of {10■2} ET in samples with angle of 45 to 90° between loading direction and RD of sheet are smaller than the correspondingly measured results.

关键词： AZ31 magnesium alloy Non-basal texture plastic deformation VPSC

Inhibiting plastic tensile instability of non-symmetric thin-walled shell component via increasing regional metal inflow based on heterogeneous pressure-carrying medium

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Chinese Journal of Aeronautics 2024年第1期37卷 391-413页

作者： Nan XIANG Yiquan SHU Pengyi WANG Menghan YANG Haoran WANG Tao HUANG Junqing GUO Fuxiao CHEN School of Materials Science and Engineering Henan University of Science and TechnologyLuoyang 471023China National Key Laboratory for Precision Heat Processing of Metals School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China College of Mechanical&Electrical Engineering Shaanxi University of Science&TechnologyXi’an 710021China Provincial and Ministerial Co-construction of Collaborative Innovation Center for Non-ferrous Metal new Materials and Advanced Processing Technology Luoyang 471023China

Heterogeneous pressure-carrying medium was employed to establish a differentiated pressure field on sheet metal in flexible die forming process in this work,which aimed at matching the non-symmetric shape of target component and improving metal inflow to avoid local tensile instability.Specifically,metal inflow corresponding to the differentiated pressure field was analytically evaluated.Forming of a typical non-symmetric shell component was experimentally and numerically studied based on the proposed method.Compared with forming processes based on the uniform pressure,difference of metal inflow in two sides of the non-symmetric component increased from 2.16 mm to 3.36 mm and metal inflow in critical region increased by 11.9%when differentiated pressure field(taking heterogeneous elastomer#4–3 for example)was employed.The resultant maximum thinning ratio decreased by 4.2% and the uniformity of shell thickness increased by 16.9%.With the decrease of Shore hardness of elastomer in the formed region,stress path in the ready-to-form region transferred towards the bi-axial tension stress state,i.e.,stress ratio(a)increased.And,stress triaxiality(η)in characteristic regions were regulated appropriately,which decreased the risk of tensile instability.It was attributed to the decreased normal pressure and frictional resistance at sheet/elastomer interface in the formed region.

关键词： Aluminum alloys Finite element method Metal forming plastic deformation Sheet metal

Modified constitutive models for Inconel 718 considering current density and temperature in electrically assisted forming process

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Chinese Journal of Aeronautics 2024年第2期37卷 524-540页

作者： Xuan CUI Rui ZHAO Min WAN School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Jiangxi Research Institute of Beihang University Jiangxi 330000China

Electrically Assisted Forming(EAF)technology has obvious advantages in material forming.To develop an effective constitutive model considering electrical effects,room temperature and electrically assisted quasi-static uniaxial tensile tests were conducted using ultrathin nickelbased superalloy plates with a thickness of 0.25 mm.The research focused on the two most widely recognized effects:the Joule thermal and the electric athermal effects.The mechanism of current action can be divided into two scenarios:one considering the Joule thermal effect only,and the other considering both effects simultaneously.Two basic constitutive models,namely the Modified-Hollomon model and the Johnson-Cook(J-C)model,were selected to be optimized through the classification of two different situations,and four optimized constitutive models were proposed.It was found that the J-C model with simultaneous consideration of the Joule thermal effect and electric athermal effect had the best prediction effect by comparing the results of these four models.Finally,the accuracy of the optimization model was verified by finite element simulation of the electrically assisted stretching optimization model.The results show that the constitutive model can effectively predict the temperature effect caused by the Joule heat effect and the athermal effect of current on the material.

关键词： Joule heating Elastoplasticity plastic deformation Superalloys Constitutive models