W80-Cu20复合材料热变形行为及加工图研究

Thermal deformation behavior and processing map of W80-Cu20 composite by hot compressing

摘要:

采用Gleeble-1500热模拟机研究了W80-Cu20(wt.％)复合材料在变形温度为810~970 ℃和应变速率为0.01~10 s_^-1条件下真应变达0.69的热变形行为,基于改进动态材料模型(MDMM)和Malas’s准则建立功率耗散图和热加工图,结合微观组织确定出合理热加工参数,并对材料的损伤方式进行分析。结果表明：W80-Cu20复合材料的应力-应变曲线表现出典型的动态再结晶型特征,峰值应力随变形温度的降低和应变速率的增加而增加；确定出W80-Cu20复合材料的合理热加工区域为：840~885℃、0.2~1.42 s_^-1和885~917℃、0.83~2.05 s_^-1；W80-Cu20复合材料的损伤方式主要有Cu相撕裂、W-Cu界面分离、W-W界面分离以及W颗粒破碎。

Abstract:

The thermal deformation behavior of W80-Cu20 composites was investigated by hot compression with Gleeble-1500 thermal simulation system in the temperature range of 810-970℃ and strain rate range of 0.01~ 10s_^-1 up to a true strain of 0.69. Based on modi?ed dynamic materials model (MDMM) and Malas"s criterion, the power dissipation map and processing map were established. Combined with microstructure, the reasonable parameters of hot processing were determined. And the damage formation of W80-Cu20 composite was analyzed. The results show that the stress-strain curves of W80-Cu20 composite are typical dynamic recrystallization (DRX) type curves, and the peak stress increases with the decreasing of deformation temperature and the increasing of strain rate. The preferable processing zones of W80-Cu20 composite were determined as follows: 840-885 ℃, 0.2-1.42 s_^-1 and 885-917℃, 0.83-2.05 s_^-1. The damage modes of W80-Cu20 composites involve Cu phase rupture, W-Cu interfacial separation, W-W grain boundary separation and W-grain crack.