铸态7075铝合金均匀化过程中晶粒生长动力学研究  

Study on grain growth kinetics during homogenization process of as-cast 7075 aluminum alloy

作　　者：张俊杰 何涛 霍元明 杜向阳 陈细林 ZHANG Jun-jie;HE Tao;HUO Yuan-ming;DU Xiang-yang;CHEN Xi-lin(School of Mechanical and Automotive Engineering,Shanghai University of Engineering Science,Shanghai 201620,China)

机构地区：[1]上海工程技术大学机械与汽车工程学院,上海201620

出　　处：《塑性工程学报》2023年第12期184-191,共8页Journal of Plasticity Engineering

基　　金：国家自然科学基金资助项目(52275350);上海工程技术大学国际合作科研平台建设项目(0301006)。

摘　　要：对铸态7075铝合金进行温度分别为435、465和480℃与时间分别为8、24和36 h的单级均匀化热处理,并在优化的单级均匀化制度上进行温度为475℃与时间分别为1、4、8和12 h的双级均匀化热处理;观察了铸态7075铝合金不同均匀化制度下的晶粒尺寸演变;计算了晶粒生长指数与生长活化能,并建立了晶粒生长动力学方程。结果表明:铸态7075铝合金在465℃/24 h制度下,平均晶粒尺寸由铸态的44μm增长至95μm,晶粒增长速度较快;而均匀化温度与时间分别超过465℃和24 h后,晶粒生长速度变得缓慢。双级均匀化过程中,当保温时间超过4 h后,铸态7075铝合金平均晶粒尺寸随着保温时间的延长增加不明显。铸态7075铝合金的晶粒生长指数为3.9,活化能为144.241 kJ·mol^(-1);铸态7075铝合金平均晶粒尺寸在生长动力学模型中的预测值与实验值之间的均方差R_(MSE)与平均绝对相对误差e_(AARE)数值分别为4.951和3.565%,模型具有较高的预测精度,表明采用所建立的晶粒生长动力学模型预测铸态7075铝合金在不同均匀化处理后的晶粒尺寸是可行的。Single-stage homogenization heat treatment was carried out on as-cast 7075 aluminum alloy at 435,465 and 480℃,and time of 8,24 and 36 h,respectively.Based on the optimized single-stage homogenization scheme,double-stage homogenization heat treatment was carried out at 475℃and time of 1,4,8 and 12 h,respectively.The grain size evolution of as-cast 7075 aluminum alloy under different homogenization schemes was observed,the grain growth index and growth activation energy were calculated,and the kinetic equation of grain growth was established.The results show that the average grain size of as-cast 7075 aluminum alloy grows from 44μm in the as-cast state to 95μm under the scheme of 465℃/24 h,the grain growth is fast;whereas the grain growth rate becomes slow when the homogenization temperature and time exceeds 465℃and 24 h,respectively.During the double-stage homogenization process,when the holding time exceeds 4 h,the average grain size increases insignificantly of as-cast 7075 aluminum alloy with the prolonging of holding time.The grain growth index of the as-cast 7075 aluminum alloy is 3.9,and the activation energy is 144.241 kJ·mol^(-1).The mean square deviation R_(MSE) and the average absolute relative error e_(AARE) between the predicted and experimental values of the average grain size of as-cast 7075 aluminum alloy in the growth kinetic model are 4.951 and 3.565%,respectively,and the model has high prediction accuracy,which indicates that it is feasible for the established kinetic model to be used for the prediction of grain size of as-cast 7075 aluminum alloy after different homogenization treatments.

关 键 词：铸态7075铝合金 均匀化 晶粒尺寸 晶粒生长动力学 

分 类 号：TG166.3[金属学及工艺—热处理]