挤压Mg-Li-Zn-Ce-Y-Zr合金的热变形行为

在温度T=250~450℃,应变速率为0.001~10s-1的条件下,利用Gleeble-3500热模拟试验机对挤压Mg-7.8%Li-4.6%Zn-0.96%Ce-0.85%Y-0.30Zr合金进行高温热压缩试验,分析流变应力曲线特点。合金的流变应力曲线表现出动态再结晶特征,动态再结晶是热变形过程中的主要软化机制。流变应力峰值随温度的降低和应变速率的增大而升高。稀土相化合物和α相促进β相的动态再结晶,使α相再结晶减缓。在热变形过程中动态再结晶迅速,流变应力曲线表现为临界应变较小,加工硬化迅速被动态软化所掩盖。

Key Laboratory of Superlight Materials and Surface Technology, Harbin Engineering University, Harbin 150001, China

High-temperature hot deformation experiments were conducted on the extruded alloy Mg-7.8%Li-4.6%Zn-0.96%Ce0.85%Y-0.30Zr at T=250-450 °C and strain rates of 0.001-10 s-1 using a Gleeble 3500 machine. The stress-strain curves of the alloy were analyzed. The curves show the characteristics of dynamic recrystallization, which is the main softening mechanism during the hot deformation processing. The peaks of the stress-strain curves become higher as the temperature decreases and the strain rate increases. The rare earth phase compound and α phases promote the dynamic recrystallization of β phases and slow down the dynamic recrystallization of α phases. In the process of the hot deformation, the dynamic recrystallization conducts quickly, the critical strain is lower in the stress-strain curves and dynamic softening covers the strain hardening effect.