采用Gleeble-1500D热模拟试验机,对Cu-Cr-Zr合金在应变速率为0.001~10 s-1、变形温度为650~850 ℃的高温变形过程中的变形行为(流变应力和显微组织)进行研究。根据动态材料模型计算并分析该合金的热加工图,并结合变形显微组织观察确定该合金在实验条件下的高温变形机制及加工工艺。结果表明:流变应力随变形温度的升高而减小,随应变速率的提高而增大。从流变应力、应变速率和温度的相关性,得出该合金高温热压缩变形时的热变形激活能(Q)为392.5 kJ/mol,同时利用逐步回归的方法建立该合金的流变应力方程。利用热加工图确定热变形的流变失稳区,并且获得了实验参数范围内热变形过程的最佳工艺参数:温度范围为750~850 ℃,应变速率范围为0.001~0.1 s-1,并利用热加工图分析了该合金不同区域的高温变性特征以及组织变化。
The high temperature deformation behaviors (flow stress and microstructure) of Cu-Cr-Zr alloy were investigated by compressive tests on Gleeble-1500D thermal-mechanical simulating tester in the strain rate range of 0.001-10 s-1 and temperatures range of 650-850 ℃. Based on dynamic materials model, the processing maps were established and analyzed. Combined with the microstructure observation the hot deformation mechanism and process of Cu-Cr-Zr alloy were worked out. The results show that the flow stress decreases with the increase of temperature and increases with the increase of strain rate. The hot deformation activation energy Q=392.5 kJ/mol is obtained and the flow stress constitutive equation is established from the correlativity of flow stress, strain rate and temperature by stepwise regression analysis. The instability zones of flow behavior can be recognized by the processing maps. The optimum processing parameters of hot deformation in the range of this experiment can also be attained by the processing maps,in which the hot temperature range is 750-850 ℃ and the strain rate range is 0.001-0.1 s-1. The hot deformation characteristics and microstructures were also analyzed with the processing maps.