摘要
采用Gleeble-1500热/力模拟系统,研究热轧的AZ31镁合金板材在应变速率0.01,0.1,1,5和10 s-1,变形温度473～723 K,预设最大变形量80%条件下的高温塑性变形行为。采用实验得到的真应力-真应变曲线,分析合金流变应力与应变速率、变形温度之间的关系,计算合金高温变形的材料参数和激活能;用Zener-Hollomon参数法建立合金高温变形的本构关系,并比较实测应力与计算得到的应力。研究结果表明:AZ31镁合金高温变形时受应变速率的影响较大,应变速率小于1 s-1时(573～723 K),合金的真应变接近100%,但当应变速率大于5 s-1时,实验温度范围内合金的真应变都小于60%。AZ31镁合金高温变形的流变应力-应变速率-变形温度的关系可用双曲正弦函数描述,激活能随应变速率和变形温度的提高,从110.4 kJ/mol升高到163.2 kJ/mol。实验获得的AZ31镁合金应力-应变本构方程的计算结果与实验结果较吻合。
The plastic deformation simulation of AZ31 magnesium alloy at elevated temperature was performed on Gleeble-1500 hot simulator with strain rates of 0.01,0.1,1,5 and 10 s-1 over a temperature range from 473 to 723 K and the maximum deformation degree of 80%.According to the obtained true stress-true strain curve,the relationship between flow stress and deformation temperature as well as strain rate were analyzed and the materials parameters and the activation energy were calculated.The constitutive relationship was established with Zener-Hollomon parameter and a comparison between the measured stresses and calculated stresses was made.The results show that the flow stress increases with the increase of strain rate at constant temperature,and decreases with the increase of deformation temperature at constant strain rate,and there are kinds of flow stress in different deformation models.The established constitutive relationship can reflect the change of flow stress during hot deformation.
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2010年第5期1749-1755,共7页
Journal of Central South University:Science and Technology
基金
国家科技支撑计划项目(2006BAE04B02-3)
关键词
镁合金
流变应力
变形激活能
本构关系
magnesium alloy
flow stress
deformation activation energy
constitutive relationship
