7075-T6高强铝合金温热变形本构方程及热加工图

Warm deformation constitutive equation and thermal processing map of 7075-T6 high strength aluminum alloy

为了获得7075高强铝合金的温热成形合理变形的工艺参数,采用Gleeble-3500热模拟试验机测试7075-T6铝合金的应力-应变曲线。研究了该合金在变形温度为150~300℃和应变速率为0.01~10 s^(-1)条件下的流变行为,并基于Arrhenius本构方程建立了0.3~0.6应变下7075-T6铝合金的热加工图,最后结合金相显微组织验证了热加工图的可靠性和实用性。结果表明:7075-T6铝合金对变形温度、应变速率、应变量具有高度敏感性,热形变激活能Q=291.151 kJ·mol^(-1);修正后的Arrhenius本构方程的拟合结果良好,相关系数r值与平均绝对误差AARE分别为99.65%和5.54%,能较好地预测7075-T6铝合金的流变行为;在应变为0.6时,最佳的温热加工安全区域范围为温度为250~300℃、应变速率为0.01~0.05 s^(-1)。

In order to obtain the reasonable deformation process parameters of warm forming for 7075 high strength aluminum alloy,the stress-strain curve of 7075-T6 aluminum alloy was tested by thermal simulation testing machine Gleeble-3500,and the rheological behavior of 7075-T6 aluminum alloy under the conditions of the deformation temperature of 150-300℃and the strain rate of 0.01^(-1)0 s^(-1)was studied.Then,the thermal processing map of 7075-T6 aluminum alloy under the strain of 0.3-0.6 was established based on Arrhenius constitutive equation,and the reliability and practicability of the thermal processing map were verified by metallographic microstructure.The results show that 7075-T6 aluminum alloy is highly sensitive to deformation temperature,strain rate and strain amount,and the thermal deformation activation energy Q is 291.151 kJ·mol^(-1).The fiting result of the modified Arrhenius constitutive equation is good,and the correlation coefficient r value and the average absolute error AARE are 99.65%and 5.54%respectively,which can better predict the rheological behavior of 7075-T6 aluminum alloy.When the strain is 0.6,the best warm processing safe zone range is the temperature of 250-300℃and the strain rate of 0.01-0.05 s.