铝锶合金高温塑性变形行为及本构方程

摘要

采用Gleeble?1500型热模拟试验机进行高温压缩实验,结合连续挤压工艺制定热压缩实验方案,研究铝锶合金高温塑性变形行为,分析变形温度、应变速率对铝锶合金热变形过程中流变应力和Al4Sr相形态的影响,并采用线性回归的方法建立铝锶合金高温下的本构方程.结果表明:铝锶合金的热塑性变形软化机制以动态回复为主;在热变形过程中流变应力随变形温度的升高而减小,随应变速率的增大而增大;变形温度为400 ℃时Al4Sr相破裂严重,而当温度为500 ℃时Al4Sr相具有韧性而易于弯曲;可用包含Zener-Hollomon参数的Arrhenius双曲正弦模型描述其热变形行为.%The pyroplastic deformation experiment of Al-Sr alloy was studied on the Gleeble-1500 thermal-mechanical simulator, which was based on the continuous extrusion process. The pyroplastic deformation behavior of Al-Sr alloy was systematically studied the effects of deformation temperature and strain rate on the flow stress and Al4Sr phase of Al-Sr alloy during hot deformation were analyzed, and the constitutive equation of Al-Sr alloy by linear regression analysis was established. The results show that the main softening mechanism of the Al-Sr alloy under the pyroplastic deformation is dynamic recovery; and the rheological stress decreases with increasing the temperature, and increases with increasing the strain rate. When the deformation temperature was 400 ℃, the Al4Sr phase break seriously; once the deformation temperature was 500 ℃, the particles become ductile and flexible. The thermal deformation behavior can be described by the Arrhenius hyperbolic sine equation with Zener-Hollomon parameters.