W-20Cu复合材料热变形行为及本构关系

Thermal deformation behavior and constitutive relationship of W-20Cu composites

通过热模拟压缩试验研究了W-20Cu复合材料在应变速率为0.01~5 s^(-1)、温度为850~1000℃时的高温热变形行为。采用扫描电镜对材料压缩变形后的显微组织进行了观察和研究。结果表明:W-20Cu复合材料具有较高的应变速率强化效应和温度软化效应;热变形加工理想条件为900~950℃,应变速率不大于1 s^(-1);材料热变形过程中,具有明显的条状Cu聚集现象,促使材料更致密,且高温、低应变速率致密效果更显著。利用试验数据,建立材料的Arrhennius本构方程,并对方程参数进行真应变的多项式函数关系修正与拟合,通过对比分析,修正后的本构方程能很好描述材料高温变形行为。

The high temperature thermal deformation behavior of W-20 Cu composites at strain rates ranging from0.01-5 s^(-1)and temperature ranging from 800-1000℃was studied by thermal simulation compression test.The microstructure after material compression deformation was observed and studied by SEM.The results show that W-20 Cu composites have high strain rate strengthening effect and temperature softening effect.The ideal condition for thermal deformation processing is 900-950℃,and the strain rate should below 1 s^(-1).In the process of material thermal deformation,there is an obvious Cu stripe aggregation phenomenon,which promotes the densification of materials,and the densification effect of high temperature and low strain rate is more significant.The Arrhennius constitutive equation of the material is established by using the experimental data and the polynomial function relation of true strain is modified and fitted to the parameters of the equation.Through comparative analysis,the modified constitutive equation can describe the high temperature rheological behavior of materials well.