Duan Yali, Yu Jianmin, Dong Beibei, Zhang Huifang, Meng Mu, Cheng Mei, Zhang Zhimin, Zhang Baohong, Hao Hongyuan, Xu Ping, Liu Huiling
College of Materials Science and Engineering, North University of China, 3 Xueyuan Road, Taiyuan 030051, China.
Department of Mechanical and Electrical Engineering, Taiyuan City Vocational College, 3 Xinghua Street, Taiyuan 030027, China.
Materials (Basel). 2022 Jan 29;15(3):1057. doi: 10.3390/ma15031057.
Rotating backward extrusion (RBE) is one of severe plastic deformation (SPD) methods used to produce cylindrical components with a very large strain by a single pass. In this study, the microstructure and texture evolution in the different regions of Mg-12Gd-4Y-2Zn-0.5Zr (wt.%) alloys via RBE process were investigated by using optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron back-scatter diffraction (EBSD). The results showed that the cup-shaped sample formed by RBE process exhibited typical gradient microstructure expanding from its inner wall to outer wall along the radial direction (RD). The average grain size of the RBEed sample decreased when the radius decreased from the edge region to the center region along the RD, which was attributed to the different strains and strain rates in the different regions. It also could be observed that the center region showed highest deformation and the edge region exhibited the lowest deformation in the RBEed sample along the RD. In addition, the grain refinement mechanisms of the experimental alloy containing long-period stacking ordered (LPSO) phases after RBE with 100 N were continuous dynamic recrystallization (CDRX), discontinuous dynamic recrystallization (DDRX) and particle stimulated nucleation (PSN).
反向旋转挤压（RBE）是一种严重塑性变形（SPD）方法，用于通过单次加工生产具有非常大应变的圆柱形部件。在本研究中，通过光学显微镜（OM）、X射线衍射（XRD）、扫描电子显微镜（SEM）和电子背散射衍射（EBSD）研究了Mg-12Gd-4Y-2Zn-0.5Zr（wt.%）合金在RBE过程中不同区域的微观结构和织构演变。结果表明，通过RBE工艺形成的杯形样品呈现出典型的梯度微观结构，沿径向（RD）从内壁向外壁扩展。沿RD方向，当半径从边缘区域向中心区域减小时，RBE处理后样品的平均晶粒尺寸减小，这归因于不同区域的应变和应变速率不同。还可以观察到，沿RD方向，RBE处理后样品的中心区域变形最大，边缘区域变形最小。此外，100 N反向旋转挤压后含长周期堆垛有序（LPSO）相的实验合金的晶粒细化机制为连续动态再结晶（CDRX）、不连续动态再结晶（DDRX）和粒子激发形核（PSN）。
