Peng Shunli, Wu Yunxin, Zhang Tao, Xie Qiumin, Yuan Zhongyu, Yin Lan
Light Alloy Research Institute, Central South University, Changsha 410083, China.
State Key Laboratory of High-Performance Complex Manufacturing, Central South University, Changsha 410083, China.
Materials (Basel). 2023 Mar 24;16(7):2587. doi: 10.3390/ma16072587.
The thermal deformation behavior of the Mg-Gd-Y-Zr-Ag alloy was studied by isothermal hot compression tests at high temperatures. The flow stress increased with increased strain rates and decreased temperatures, first increasing and finally remaining stable with increased strain. A hot processing map was built. Using the processing map and microstructural analysis, the temperature should remain at 673-773 K for this alloy to ensure the deformation quality. The primary softening mechanism is discontinuous dynamic recrystallization (DDRX). Rising temperatures and declining strain rates facilitated the emergence and growth of Dynamic recrystallization (DRX) grains. An original JC (O-JC) model and a modified JC (M-JC) model were established. The M-JC model indicated a better prediction than the O-JC model. Still, it was deficient in predicting flow stresses with insufficient coupling effects. Hence, based on the M-JC model, a newly modified JC (NM-JC) model, which further enhances the interaction between strain and strain rate as well as strain and temperature, is proposed. Its projected values can better align with the tested values.
通过高温等温热压缩试验研究了Mg-Gd-Y-Zr-Ag合金的热变形行为。流变应力随应变速率的增加和温度的降低而增大，随应变的增加先增大后趋于稳定。构建了热加工图。利用加工图和微观组织分析，该合金的温度应保持在673-773K以确保变形质量。主要软化机制为不连续动态再结晶（DDRX）。温度升高和应变速率降低促进了动态再结晶（DRX）晶粒的出现和长大。建立了原始的JC（O-JC）模型和改进的JC（M-JC）模型。M-JC模型的预测效果优于O-JC模型。然而，它在预测耦合效应不足的流变应力方面存在缺陷。因此，基于M-JC模型，提出了一种新的改进JC（NM-JC）模型，该模型进一步增强了应变与应变速率以及应变与温度之间的相互作用。其预测值能更好地与试验值吻合。
