碳化硅颗粒增强6168铝基复合材料热变形本构关系

利用Gleeble-3500热模拟试验机研究碳化硅颗粒增强6168铝基复合材料(SiCp/6168Al)在变形温度为340~540 ℃、应变速率为0.001~10 s-1、真应变为0.7的条件下的热变形行为。结果表明:应变速率和变形温度对流变应力有明显的影响，在应变速率相同的条件下，流变应力随变形温度的升高而降低，相同的变形温度下，随应变速率的增加，流变应力也随之升高。采用双曲正弦模型求解SiCp/6168Al复合材料在不同真应变ε下的材料常数，并使用5次指数函数拟合出n、lnA、α和Q与真应变ε的关系式，建立流变应力σ与真应变ε的本构方程。利用该方程可以计算任意变形条件下的流变应力，该模型能较好地反映该复合材料的实际热变形行为。  

Constitutive Relationship of Hot Deformation Behavior for Al Alloy Matrix Composites 6168 Reinforced by SiC Particulates

The deformation behavior of aluminium matrix composite reinforced by SiC particulates is investigated by compression tests on Gleeble 3500 thermal simulator machine. The tests are performed in the temperature ranging from 340 to 540℃, strain rate from 0. 001 to 10 s-1 , and true strain value of 0.7. The results show that the strain rate and deformation temperature have a significant effect on the flow stress. The flow stress decreases with the deformation temperature increase in same strain rate. And the flow stress in- creases with strain rate increase in same temperature. The flow stress of the SiCp/6168Al during high temperature deformation can be represented by a Zenter-Hollomon parameter in the hyperbolic Arrhenius-type equation. The relationship of Q, lnA, n, a and e can be expressed by 5 exponential function, the model can calculate the flow stress of any deformation condition, and can accurately reflect the thermal deformation of SiCp/6168Al.