中文摘要：

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。

英文摘要：

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.