5083铝合金的热变形组织演变及晶粒度模型

摘要

The influences of hot deformation condition upon the microstructure of 5083 aluminum alloy during compressing in the temperature range of 300-450 ℃, the strain rate range of 0.01-1 s-1 and the strain range of 0.36-1.2 were studied by means of isothermal compressive deformation, optical microscopy and transmission electron microscopy.The results show that both the increase of deformation temperature and the decrease of strain rate benefit dynamic recrystallization, which results in the decrease of the dislocation density of 5083 aluminum alloy and the increase of the recrystallization grains size.With the increase of strain of 5083 aluminum alloy, the dislocation density decreases and the volume fraction of dynamic recrystallization increases.According to the exponential model of phenomenological theory and the linear regression method, the dynamic recrystallization grain size model of 5083 aluminum alloy during the thermoplastic deformation was constructed, and the model calculation value coincided well with the experimental data, as the average relative error was only 4.6%.%通过等温压缩实验、光学显微镜与透射电镜研究了变形温度300~450 ℃、应变速率0.01~1 s-1、真应变0.36~1.2范围内变形条件对5083铝合金热变形组织演变的影响.结果表明:升高热变形温度或降低应变速率均可促进5083铝合金的动态再结晶发生,使变形后5083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,变形后合金的位错密度降低,动态再结晶程度增大.根据唯象理论的指数模型,利用线性回归方法建立了5083铝合金动态再结晶晶粒度模型,模型计算值与实测值吻合良好,平均相对误差仅为4.6%.