7075铝合金的热激活变形行为与唯象本构关系

利用热物理模拟机Gleeble1500进行多组圆柱试样的热物理模拟压缩试验,试验温度为250～450℃,应变速率为0.01～10 s-1.结果表明,7075铝合金热压缩温度在300、350、400和450℃时流变行为呈近稳态,而在250℃时呈非稳态.应用多元线性同归方法分析计算了7075合金唯象本构模型所需的一组系数及热变形的激活能.获得了能够较精确表示7075合金材料的流动应力与温度、应变速率和应变之间关系的唯象本构模型,为塑性成形模拟提供了所需的基本模型.

Relationship Between Hot Activation Forming Behavior and Phenomenological Constitutive of 7075 Aluminum Alloy

Several series of billet samples were compressed on heat physical simulation machine Gleeble1500 in the range of deformation temperature from 250℃ to 450℃,strain rate from 0.01 s~(-1) to 10 s~(-1).The results show that flow behavior of the material is unstable at 250 ℃,while near-steady-state at 300 ℃,350 ℃,400 ℃,450 ℃.A group of coefficients needed by the phenomenological constitutive model of 7075 aluminum and the activation energy of hot deformation are calculated by the method of multiple linear regression.The phenomenological constitutive model which can accurately describe the relationship between flow stress and temperature,strain rate and strain is achieved,and it offers the basic model for plastic forming simulation.