应力三轴度对7050铝合金热塑性成形损伤和晶粒尺寸的影响  

Effects of Stress Triaxiality on Damage and Grain Size of 7050Aluminum Alloy in Thermo-plastic Forming

作　　者：刘德政 李炎 罗静 王友 Liu Dezheng;Li Yan;Luo Jing;Wang You(School of Mechanical Engineering,Hubei University of Arts and Science)

机构地区：[1]湖北文理学院机械工程学院,湖北襄阳441053

出　　处：《特种铸造及有色合金》2020年第6期581-586,共6页Special Casting & Nonferrous Alloys

基　　金：教育部科技发展中心高校产学研创新基金-新一代信息技术创新基金资助项目(2018A04017)。

摘　　要：在应变速率为0.01~10s-1、温度为423~623K下,采用Gleeble1500热物理模拟机并结合有限元法对7050铝合金进行单轴拉伸试验与模拟,分别确定了该材料流变应力、动态再结晶及热塑性损伤的模型参数。然后,基于布里奇曼(Bridgman)法建立了不同缺口半径的7050铝合金圆棒拉伸有限元分析模型,研究了不同温度条件下应力三轴度对7050铝合金热塑性成形损伤的影响。最后,利用DEFORM-3D软件模拟了该合金在不同应力三轴度下的晶粒长大规律。结果表明,在相同温度下,塑性损伤值随应力三轴度的增大而增加,当应力三轴度高于0.7后,塑性损伤值基本保持稳定;在相同应力三轴度下,塑性损伤值随温度的升高而降低,当温度高于523K以后,塑性损伤值基本保持稳定;随应力三轴度的增加晶粒尺寸先减小后增加。The uniaxial tensile tests of 7050aluminum alloy were performed at 0.01~10s-1 and 423~623Kby Gleeble1500thermo-simulator combining with finite element method(FEM).The parameters of flow stress,dynamic recrystallization and thermo-plastic damage were determined firstly by experiment and FE uniaxial tensile tests.Furthermore,the effects of stress triaxiality on the thermo-plastic forming damage of 7050aluminum alloy under different temperatures were investigated via the FE analysis for different notched bars based on the Bridgman method.Lastly,the DEFORM-3Dsoftware was adopted to analyze the process of grain size growth of the 7050aluminum alloy under the different stress triaxiality.The results indicate that at the same temperature,the plastic damage value is increased with the increase of the stress triaxiality degree,while the damage value remains stable when the stress triaxiality is more than 0.7.At the same stress triaxiality,the plastic damage value is decreased with the increase of the temperature,while the damage value remains stable when the temperature reaches to 523Kand the grain size of 7050aluminum alloy is decreased with the increase of stress triaxiality ranged between 0.33~0.50,and the grain size is increased with the increase of stress triaxiality ranged between 0.5~0.9.

关 键 词：应力三轴度 7050铝合金 热塑性成形 损伤 晶粒尺寸 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TB301[金属学及工艺—金属材料]