7A85铝合金热压缩流变行为与本构方程研究
Study on Flow Behavior and Constitutive Equation of 7A85 Aluminum Alloy During Hot Compression
贾逢博, 易幼平, 黄施全, 李 云
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作者单位：中南大学 机电工程学院, 湖南 长沙 410083
中文关键字：7A85铝合金； 压缩试验； 流变应力； 本构方程
英文关键字：7A85 aluminum alloy; compression experiment; flow stress; constitutive equation
中文摘要：通过在Gleeble-1500 热模拟试验机上进行高温压缩试验，研究了7A85 铝合金在变形温度为250～450 ℃、应变速率为0.001～1 s-1条件下的高温流变行为。研究表明，7A85铝合金在热压缩过程中发生了明显的动态回复与动态再结晶；变形抗力随温度的降低而增加，当温度低于300 ℃时变形抗力增加明显，同时变形抗力随应变速率的增大而增大；应变速率和流变应力之间满足指数关系，温度和流变应力之间满足Arrhenius 方程；采用线性回归方法获得了7A85铝合金高温条件下流变应力的本构方程。
英文摘要：The flow behavior of 7A85 aluminum alloy was investigated on the condition of temperature range from 250 ℃ to 450 ℃ and strain rates range from 0.001 s-1 to 1 s-1 based on hot compression experiment using Gleeble-1500 thermo-mechanical simulator. The results show that the dynamic recovery and dynamic recrystallization of 7A85 aluminum alloy occur clearly during hot compression. The deformation resistance increases with the decease of temperature. Especially, the tendency becomes more obvious below 300 ℃. Meanwhile, the deformation resistance increases with the increase of strain rate. The relationship between the strain rate and flow stress is accordant with the exponential relation, and the relationship satisfies Arrhenius equation. Finally, the constitutive equation for flow stress of 7A85 aluminum alloy at high temperature is obtained by linear regression.