7075铝合金热变形行为和组织演变  

Hot deformation behavior and microstructure evolution of 7075 aluminum alloy

作　　者：李琛 王和斌 欧平 王航 王俊峰[1] 张济山[2] Li Chen;Wang Hebin;Ou Ping;Wang Hang;Wang Junfeng;Zhang Jishan(Faculty of Materials Metallurgy and Chemistry,Jiangxi University of Science and Technology,Ganzhou Jiangxi 341000,China;State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]江西理工大学材料冶金化学学部,江西赣州341000 [2]北京科技大学新金属材料国家重点实验室,北京100083

出　　处：《金属热处理》2023年第6期147-156,共10页Heat Treatment of Metals

基　　金：北京科技大学新金属材料国家重点实验室开放基金(2022Z-18);江西省教育厅科技项目(GJJ180479)。

摘　　要：利用MMS-100热/力模拟试验机对固溶态7075铝合金进行了热压缩试验,构建了能描述合金在温度为350~450℃、应变速率为0.01~10 s^(-1)条件下流变应力规律的本构方程,基于动态材料模型和显微组织确定了该合金热加工的最佳工艺窗口。结果表明,475℃固溶温度下,MgZn_(2)相可全部回溶于基体,随固溶时间延长,Al_(2)CuMg和Al_(7)Cu_(2)Fe回溶量增多;合金的流变应力随着温度的降低和应变速率的增加而增大,热变形激活能Q=153.724 kJ/mol;功率耗散系数随温度的升高和应变速率的减小逐渐增大,流变失稳区随应变的增大向高应变速率方向移动,合金的热加工最佳工艺窗口为变形温度420~450℃,应变速率0.01~0.02 s^(-1)。Hot compression test was carried out for the as-solid solution treated 7075 aluminum alloy by MMS-100 thermo-mechanical simulator and the flow stress constitutive model of the alloy was constructed at 350-450℃and strain rate among 0.01-10 s^(-1).Based on the dynamic material model and microstructure,the optimum process window for the hot deformation was determined.The results show that after solution treatment at 475℃,the MgZn_(2)phase is all dissolved back into the matrix,and with the increase of solution treatment time,the fraction of Al_(2)CuMg and Al_(7)Cu_(2)Fe dissolved in matrix increases.The flow stress of the alloy increases with the decrease of temperature and increase of strain rate,and the hot deformation activation energy calculated is approximately Q=153.724 kJ/mol.The power dissipation coefficient gradually increases with the temperature increasing and strain rate decreasing,the flow instability zones move to higher strain rate with the increase of strain,the optimum processing window of the alloy is deformation temperature of 420-450℃and strain rate of 0.01-0.02 s^(-1)

关 键 词：7075铝合金 热变形 本构方程 热加工图 组织演化 

分 类 号：TG146.21[一般工业技术—材料科学与工程]