(西北工业大学材料学院 凝固技术国家重点实验室，西安 710072)
摘 要: 通过等温压缩试验和定量金相分析研究挤压态7075铝合金在变形温度为250~450℃、应变速率0.01~10 s-1下的变形行为和组织演化规律，得到不同变形条件下的真应力—应变曲线、平均晶粒尺寸、再结晶晶粒尺寸及再结晶分数。基于Yada模型通过统计回归建立挤压态7075铝合金动态再结晶经验模型并进行验证。结果表明：所建立的Yada再结晶模型误差平均值达到5%；通过二次开发实现了再结晶模型与Deform-3D软件的结合，并进行单向墩粗模拟验证，结果表明该模型预报精度较好。采用所建立的Yada再结晶模型研究7075铝合金三通件多向加载成形过程组织演化，获得加载路径对工件晶粒尺寸特征的影响规律。
关键字: 7075铝合金；再结晶模型；数值模拟
（State Key Laboratory of Solidification Processing, School of Materials Science and Engineering,
Northwestern Polytechnical University, Xi’an 710072, China）
Abstract:Using isothermal compression test and quantitative metallographic analysis, the deformation behavior and microstructure evolution of as-extruded aluminum alloy 7075 were studied within a temperature range of 250-450 ℃ and a strain rate range of 0.01-10s-1. The true stress—strain curves, average grain size, recrystallized grain size, recrystallization volume fraction under different deformation conditions were obtained. Based on Yada recrystallization model, an empirical dynamic recrystallization model of the as-extruded aluminum alloy 7075 was established by means of statistical regression method. The results show that the average error of the model is less than 5%. Through secondary development, the established recrystallization model was implanted in the software Derform-3D, simulation validation shows that the prediction accuracy of the model can meet the requirements. Then, adopting the established model, the microstructure evolution in multi-way loading forging process of the as extruded 7075 triple valve workpiece was studied, and the grain size and distribution laws of the workpiece under the two loading paths were obtained.
Key words: 7075 aluminum alloy; recrystallization model; numerical simulation
