5A30铝合金热变形的流变应力及材料常数

The flow stress and material constants of thermal deformation for 5A30 aluminum alloy

在Gleeble-1500热模拟试验机上,采用高温等温压缩试验,研究了5A30铝合金在300～500℃温度范围及应变速率在0.001～1s-1内压缩变形的流变应力变化规律,采用数学回归及最小偏差法求出了该合金的材料常数,建立了该合金流变应力与Zener-Hollomon参数的线性关系式.结果表明,该合金为正应变速率敏感材料,流变应力随变形温度升高而降低,随应变速率升高而增大;该合金的材料常数包括变形激活能Q为160.94kJ/mol,应力水平参数α为0.0184mm2/N,应力指数n为3.314,结构因子A为3.058×109s-1;合金流变应力模型可表达为σ=54.31ln{(Z/3.058×109)1/3.314+[(Z/3.058×109)2/3.314+1]1/2}.

The flow stress characteristics of 5A30 aluminum alloy were investigated by isothermal compression testing method with Gleeble-1500 thermal simulator under the temperature and strain rate range from 300 to 500℃ and 0.001 to 1 s-1 respectively. The material constants of alloy were derived by regression method and minimized deviation criterion,the linear relationship of the flow stress to Zener-Hollomon parameter was established. The results show that the alloy is sensitive material to strain rate positively,and the flow stress increases with decreasing deformation temperature and increasing of strain rate. The material constants of the alloy,including deformation activation energy Q as 160.94KJ/mol,stress-level coefficient α as 0.0184 mm2/N,stress exponential n as 3.314 and structual factor A as 3.058×109 s-1. The model of flow stress can be described as σ=54.31ln{（Z/3.058×109）1/3.314＋[（Z/3.058×109）2/3.314＋1]1/2}.