AZ31镁合金在热压缩过程中的变形行为

Deformation Behavior of AZ31 Magnesium Alloy during Hot Compression Process

用Gleeble-1500D型热模拟试验机对AZ31镁合金在变形温度200～400℃、应变速率0.01～1 s^(-1)条件下进行热模拟压缩试验,研究了该合金的热变形行为,并获得了其变形的主要特征参数,建立了高温流变数学模型和功率耗散图。结果表明:热压缩时,AZ31镁合金流变应力受温度和应变速率影响显著,应力-应变曲线呈现出明显的动态再结晶特征,温度越高、应变速率越小,动态再结晶越容易发生;热变形过程受变形激活能控制,得到流变应力的关系式lnε=35.74+9.96ln[sinh(0.01σ)]-1.96×10~5/RT,耗散系数随温度升高和应变速率降低而逐渐增大。

Hot compression experiments of AZ31 magnesium alloy had been carried out at deformation temperature of 200- 400℃ and strain rate of 0. 01- 1 s^-1 on a Gleeble-1500D thermal simulator. The hot deformation behavior was investigated and the main deformation characteristic parameters were acquired. Then the mathematical model of high temperature flow stress and the iso-efficiency map were established. The results show that the temperature and strain rate dramatically affected the flow stress during hot compression process of AZ31 magnesium alloy and the stress-strain curves showed an obvious characteristic of dynamic recrystallization. The dynamic recrystallization easily occured with higher temperature and smaller strain rate. And the hot deformation process was controlled by deformation activation energy. The flow stress was expressed by Inε=35. 74± 9. 96In[sinh（0. 01a）]-1.96 ×10^5/RT. The iso-efficiency coefficient increased with the increasing temperature and decreasing strain rate.