(1. 湖南大学 汽车车身先进设计制造国家重点实验室，长沙 410082；
2. 湖南大学 材料科学与工程学院，长沙 410082；
3. 重庆长安汽车股份有限公司 汽车工程研究院车身技术研究所，重庆 401120)
摘 要: 结合Gleeble−1500热模拟机在变形温度为300~500 ℃，应变速率为0.01~10 s−1 条件下通过等温压缩实验研究6061铝合金的流变应力行为，采用未考虑温升效应的参数反求法及考虑温升效应的参数反求法求解流变应力方程参数，并与回归统计法得到的结果进行对比分析。结果表明：采用未考虑温升效应的参数反求法求解流变应力方程参数具有高效、准确等优点，计算峰值应力平均误差为5.17 MPa；与有限元软件结合考虑温升效应的参数反求法能够更好地描述真实的材料变形过程；3种方法得到的流变应力方程参数的偏差小于6.28%，采用多岛遗传算法与模拟退火算法反求得到的流变应力方程参数具有较好的一致性与可靠性，参数反求法可替代传统回归统计法快速获得材料大变形条件下流变应力方程参数。
关键字: 6061铝合金；参数反求；流变应力方程；热压缩变形；有限元
6061 aluminum alloy during hot deformation with inverse methods
（1. State Key Laboratory of Advanced Design and Manufacture for Vehicle Body,
Hunan University, Changsha 410082, China;
2. College of Materials Science and Engineering, Hunan University, Changsha 410082, China;
3. Automotive Engineering Institute Body Technology Research Department,
Chongqing Chang’an Automobile Co. Ltd., Chongqing 401120, China）
Abstract:The flow stress behaviors of 6061 aluminum alloy were studied by compression test at the deformation temperature of 300−450 ℃ and strain rate of 0.01−10 s−1 on Gleeble−1500 system. With the experimental data, the material parameters for the hot deformation constitutive equation were obtained by inverse methods and finite element (FE) simulation based on the inverse methods and compared with the results obtained by regression statistics methods. The results show that the inverse method is efficient and accurate. The average error of flow stress of 6061 aluminum alloy is 5.17 MPa with the inverse methods. The constitutive parameters identified with FE based inverse methods can accurately describe the hot compression deformation of 6061 aluminum alloy. The deviation of constructive parameters obtained by inverse methods, FE based inverse methods and regression statistics methods is less than 6.28%. The constitutive parameters obtained by multi-island genetic algorithm and simulated annealing (SA) algorithm are reliable and robust. Under the large deformation condition, the reverse methods can substitute the traditional regression statistic methods to identify the constitutive parameters accurately and efficiently.
Key words: 6061 aluminum alloy; inverse method; flow stress equation; hot compression deformation; finite element method
