Al-Zn-Mg合金的热变形组织演化

采用Ｇｌｅｅｂｌｅ １５００热压缩模拟试验机研究了Ａｌ－Ｚｎ－Ｍｇ（７００５）合金的高温变形组织演化行为，利用ＴＥＭ分析了合金在不同压缩条件下的组织形貌特征，采用ＥＢＳＰ分析了晶粒间的取向差，研究了其动态再结晶行为，通过回归分析建立了７００５合金热变形条件与条形亚晶尺寸关系的半经验模型，合金平均亚晶大小随温度补偿应变速率Ｚ参数（Ｚｅｎｅｒ－Ｈｏｌｌｏｍｏｎ参数）的降低而增大，其倒数与Ｚ参数的自然对

MICROSTRUCTURE EVOLUTION OF Al-Zn-Mg ALLOY DURING HOT DEFORMATION

Microstructure evolution of an Al-Zn-Mg (AA7005) alloy during compression at elevated temperatures was investigated by compression on Gleeble 1500 dynamic materials test machine. TEM was employed to analyze the microstructures of the alloy and electron back scattering parttern (EBSP) was conducted to study the orientation differences between neighboring grains and hence dynamic recrystallization behavior of the alloy. Semi-empirical relations between subgrain sizes and deformation variables were constructed by linear regression. The mean subgrain size increases with decrease of temperature compensated strain rate Z, Zener-Hollomon parameter, while the reciprocal of the subgrain size has a good linear relationship with the natural logarithm of Z value, as well as that of the hyperbolic term of flow stress. Geometric dynamic recrystallization is found to be active under a critical deformation condition of in Z < 21.0, and fine equiaxed grains with high-angle boundaries develop resultantly..