6082铝合金的高温本构关系

利用Gleeble-3500热模拟机,研究6082铝合金在350℃～500℃、应变速率10-2s-1～5s-1、最大变形程度60%条件下的热压缩变形行为。得到了高温下该铝合金的真应力-应变曲线。分析流变应力与应变速率和变形温度之间的关系,建立了高温热变形的本构关系。推导出包含Arrhenius项的Zener-Hollomon参数所描述的高温流变应力表达式。为减少应变的影响,建立4阶多项式对材料参数进行拟合,得到改进的本构方程,并与实验值进行对比。结果表明,应变速率和变形温度对6082铝合金流变应力有显著影响,流变应力随变形温度的升高而降低,随应变速率的增大而增大。该合金属于正应变速率敏感材料,合金热变形过程受热激活控制,激活能为145.977kJ/mol。

Constitutive equations for hot deformation of 6082 aluminum alloy

The hot compression behavior of 6082 aluminum alloy was investigated with compression tests on Gleeble 3500 thermal mechanical simulator at the temperature range of 350℃~500℃,the strain rate range of 10-2~5s-1,and the reduction in height of 60% at the end of the tests.As the result,the true stress-strain curves were obtained.The relation of flow stress,strain rate and deformation temperature was analyzed,and the constitutive equation was found.Expression for describing the flow stress during hot compression process by Zener-Hollomon parameter including Arrhenius term was deduced.Furthermore,in order to reduce influences of strain,the values were polynomial fitted by 4th order and then the improved equation was obtained.Comparisons between the experimental and predicted flow stress were carried out.The result showed that the flow stress was affected by strain rate and temperature evidently.It increased with the increasing of strain rate and decreased with the increasing of temperature.6082 aluminum alloy is sensitive to positive strain rate.The hot deformation was controlled by activation energy whose value was 145.977kJ/mol.