7085铝合金的热变形组织演变及动态再结晶模型

Microstructure evolution and dynamic recrystallization model of 7085 aluminum alloy during hot deformation

通过等温压缩实验,系统研究热变形参数(变形温度、应变速率及应变量)对7085铝合金热变形组织演变的影响。结果表明:升高变形温度以及降低应变速率,均有利于7085铝合金的动态再结晶发生,导致变形后的7085铝合金位错密度降低,再结晶晶粒尺寸增大;随着应变量的增加,变形后的合金位错密度降低,动态再结晶体积分数增大。采用线性回归方法建立包括峰值应变方程、临界应变方程、动态再结晶动力学方程以及动态再结晶晶粒尺寸方程的7085铝合金动态再结晶模型。

The effects of hot working parameters （deformation temperature, strain rate and strain） on the microstructure evolution of 7085 aluminum alloy during compressing were studied systematically by isothermal compressive deformation. The results indicate that both the increase of deformation temperature and the decrease of strain rate are good for dynamic recrystallization, which results in the decrease of the dislocation density of 7085 aluminum alloy and the increase of the recrystallization grains size. With the increase of strain of 7085 aluminum alloy, the dislocation density decreases and the volume fraction of dynamic recrystallization increases. The dynamic recrystallization models of 7085 aluminum alloy, which contain the peak strain equation, critical strain equation, kinetics equation of dynamic recrystallization and grain size equation of dynamic recrystallization, were deduced by the linear regression method.