7150铝合金热变形行为及微观组织Flow Stress Behavior and Microstructure of 7150 Aluminum Alloy during Hot Deformation

采用Gleeble热模拟机进行热压缩实验,研究7150铝合金在变形温度为300~450℃、应变速率为0.01~10s^-1条件下的变形行为,采用Zener-Hollomon参数法构建合金高温塑性变形本构方程,并对变形后的微观组织进行分析。研究表明:7150铝合金的流变应力随应变速率增大而增大,随变形温度增大而降低。该合金热压缩变形的流变应力行为可用双曲正弦形式的本构方程描述,其参数A为4.161×10¹⁴ s^-1,α为0.01956 MPa^-1,n为5.14336,热变形激活能Q为229.7531kJ/mol。随着温度升高和应变速率降低,动态再结晶逐渐取代动态回复成为合金的主要软化机制。

The flow stress behavior and the deformation microstructure of 7150 aluminum alloy during hot compression deformation were studied by thermal simulation test using Gleeble thermal simulation machine at temperature ranging from 300℃ to 450℃ and strain-rate from 0.01s^-1 to 10s^-1. The constitutive equation of the plastic deformation of 7150 alloy at elevated temperature was obtained by introducing Zener-Hollomon parameter. The experimental results indicate that the flow stress and peak stress increase with increasing strain rate, and decrease with increasing deformation temperature, which can be described by a constitutive equation in hyperbolic sine function, whose values of related parameters A,α, n and activation energy for hot deformation Q, are 4.161×10¹⁴ s^-1, 0.01956 MPa^-1, 5.14336 and 229.7531kJ/mol respectively. With increasing the temperature and decreasing the strain rate, the main soften mechanism of the 7150 alloy transforms from dynamic recovery to dynamic re-crystallization.