Mg-Gd-Y-Zn-Zr合金旋转反挤压杯形件的组织演变和动态再结晶机制

Organization evolution and dynamic recrystallization mechanism of Mg-Gd-Y-Zn-Zr alloy rotationally counter-extruded cuprates

摘要:

本文使用传统反挤压（Conventional Backward Extrusion，CBE）和旋转反挤压（Rotational Backward Extrusion，RBE）两种工艺制备了不同的Mg-9Gd-4Y-2Zn-0.5Zr (wt.%)合金杯形件。使用OM、SEM、EBSD等测试方法对不同杯形件的对应区域进行表征。结果表明：RBE的晶粒细化能力远远大于CBE,RBE心部的晶粒细化效果最好，RBE-Ⅲ区域的动态再结晶（Dynamic Recrystallization，DRX）含量可达98.1%，平均晶粒尺寸为2.5μm。RBE的织构弱化能力也优于CBE，心部的织构强度可弱化为1.258。在RBE得到杯形件当中，其LPSO相的破碎程度也大于CBE，第二相（β相）分布的也更加均匀，析出的β相可以通过粒子刺激形核（Particles Simulated Nucleation，PSN）机制促进DRX，并通过钉扎效应抑制晶粒长大。在CBE和RBE杯形件成形过程中，其动态再结晶机制相同，为连续动态再结晶（Continuous Dynamic ecrystallization，CDRX）和不连续动态再结晶（Discontinuous Dynamic Recrystallization，DDRX）两种。

Abstract:

In this paper, different cuprates of Mg-9Gd-4Y-2Zn-0.5Zr (wt.%) alloys were prepared using Conventional Backward Extrusion (CBE) and Rotational Backward Extrusion (RBE) processes. The corresponding regions of the different cuprates were characterized using OM, SEM, EBSD and other testing methods. The results show that the grain refining ability of RBE is much larger than that of CBE, and the grain refining effect in the heart of RBE is the best, and the content of Dynamic Recrystallization (DRX) in the RBE-III region can be up to 98.1%, with an average grain size of 2.5 μm. The texture weakening ability of RBE is also better than that of CBE, and the texture strength of the core can be weakened to 1.258. In the RBE cups, the degree of crushing of the LPSO phase is also larger than that of CBE, and the distribution of the second phase (β-phase) is more uniform, and the precipitated β-phase can promote DRX through the mechanism of Particles Simulated Nucleation (PSN) and restrain the growth of the grains through the pinning effect. In CBE and RBE cup molding processes, the dynamic recrystallization mechanism is the same, which is Continuous Dynamic Recrystallization (CDRX) and Discontinuous Dynamic Recrystallization (DDRX).