Chen Ming, Ma Cong, Liu Qingjie, Cheng Ming, Wang Haolei, Hu Xiaodong
School of Mechanical Engineering and Automation, University of Science and Technology Liaoning, Anshan 114051, China.
Research Center of Magnesium Alloy Casting and Rolling Technology, University of Science and Technology Liaoning, Anshan 114051, China.
Materials (Basel). 2023 Feb 3;16(3):1320. doi: 10.3390/ma16031320.
ZK61 magnesium-alloy plate with high tensile strength and elongation is obtained by combined multipass symmetric hot rolling and asymmetric warm rolling. Deformation history considering varying strain rate obtained from the macro-finite element analysis of the selected passes are introduced into the viscoplastic self-consistent model (VPSC) as initial boundary conditions for macro- multiscale and micro-multiscale coupling analysis. VPSC simulation results show that in the initial stage of rolling deformation, the basal slip is the dominated deformation mode, supplemented by prismatic slip and pyramidal <c+a> slip. With increased rolling strain, the pyramidal <c+a> slip presents competitive relationship with basal slip, and the activation amount of {101-1} compression twins is limited. During asymmetric rolling, the basal slip is dominant, followed by the pyramidal <c+a> slip. Experimental results show that the basal texture is gradually strengthened after symmetric rolling, and grain size is refined due to the activation and recrystallization of twins. Asymmetric rolling makes the basal texture deflect 10° to the rolling direction and further refine the grain size. With the ongoing of symmetric rolling, the mechanical anisotropy of the plate weakens, and the yield strength, tensile strength, and plasticity of the material improves. In particular, after asymmetric rolling, the tensile strength in the RD and TD directions of the plate reaches 391.2 MPa and 398.9 MPa, whereas the elongation reaches 19.8% and 25.5%.
通过多道次对称热轧和非对称温轧相结合的方式获得了具有高抗拉强度和伸长率的ZK61镁合金板材。将从选定道次的宏观有限元分析中获得的考虑应变率变化的变形历史作为宏观多尺度和微观多尺度耦合分析的初始边界条件引入粘塑性自洽模型（VPSC）。VPSC模拟结果表明，在轧制变形初始阶段，基面〈a〉滑移是主导变形模式，辅以棱柱面〈a〉滑移和锥面〈c+a〉滑移。随着轧制应变增加，锥面〈c+a〉滑移与基面〈a〉滑移呈现竞争关系，{101-1}压缩孪晶的激活量有限。在非对称轧制过程中，基面〈a〉滑移占主导，其次是锥面〈c+a〉滑移。实验结果表明，对称轧制后基面织构逐渐强化，孪晶的激活和再结晶使晶粒细化。非对称轧制使基面织构向轧制方向偏转10°并进一步细化晶粒尺寸。随着对称轧制的进行，板材的力学各向异性减弱，材料的屈服强度、抗拉强度和塑性提高。特别是，非对称轧制后，板材轧制方向（RD）和横向（TD）的抗拉强度分别达到391.2MPa和398.9MPa，伸长率分别达到19.8%和25.5%。
