石墨烯增强铝基复合材料的热变形本构方程研究

Study on Hot Deformation Constitutive Equation of Graphene Reinforced Aluminum Matrix Composite

采用热模拟实验机对石墨烯增强7075铝合金复合材料进行高温热压缩实验,变形温度为300~450℃、应变速率为0.001~1 s^(-1),分析其在不同应变速率及温度条件下的高温流变应力特征,并以实验数据为基础,通过函数拟合确定包含应变、应变速率和温度等变形参数的双曲正弦本构方程。研究结果表明:铝基复合材料热压缩变形时流变应力随应变增加迅速增大,达到峰值应力后略有下降且出现锯齿状波动;给出的双曲正弦本构方程可以较好地描述流变应力与应变、应变速率及温度之间的关系,计算值与实验值吻合良好。

The high temperature compression experiment of graphene reinforced 7075 aluminum alloy composite was carried out with a thermal simulation tester.The deformation temperature was 300~450 ℃ and the strain rate was 0.001~1 s-1.The flow stress characteristics under different strain rates and temperatures were analyzed.Based on the experimental data, the hyperbolic sinusoidal constitutive equation including deformation parameters such as strain, strain rate and temperature was determined by function fitting.The results show that the flow stress of aluminum matrix composites increases rapidly with the increase of strain during thermal compression deformation, decreases slightly after reaching the peak stress and fluctuates in a zigzag manner.The relationship between flow stress and strain, strain rate and temperature can be well described by hyperbolic sinusoidal function.