采用Gleeble-3800热模拟试验机对粉末冶金法制备的31%B₄Cp/6061Al (体积分数)复合材料进行热压缩行为研究，实验温度和应变速率分别为375~525 ℃和0.001~10 s^-1。基于改进的动态材料模型(MDMM)建立了功率耗散率图和热加工图，确定了热加工的稳定区和失稳区，分析了热压缩过程中的微观组织变化。结果表明，31%B₄Cp/6061Al复合材料的变形温度和应变速率对流变应力的影响十分显著，流变应力随变形温度的降低或应变速率的升高而增加。确定了31%B₄Cp/6061Al复合材料的最优热加工参数所对应的变形温度和应变速率分别为480~525 ℃和0.01~0.04 s^-1。加工失稳区主要集中在低温高应变速率区域，并且该区域随应变的增大而增大。热压过程中应变、温度和应变速率对显微组织的变化都有显著影响，应变越大，则晶粒变形越严重，随着变形温度的升高或应变速率的降低，基体内动态再结晶晶粒尺寸明显增大。

B₄Cp/Al composite has the advantages of light weight, good stability, high neutron absorption capacity and excellent mechanical properties, and is increasingly used in nuclear industry for storage and transportation of spent fuels. However, due to the obvious difference in the mechanical properties between the reinforcement and the aluminum matrix, the deformation of B₄Cp/Al composite is quite difficult. In this study, the hot compression behavior of 31%B₄Cp/6061Al (volume fraction) composite fabricated by powder metallurgy was investigated in the temperature range of 375~525 ℃ and strain rate range of 0.001~10 s^-1 with Gleeble-3800 thermal simulator system. Based on the modified dynamic material model (MDMM), the power dissipation efficiency and processing maps were established, the instability zones and stable area of hot deformation were determined, and the microstructure evolution during hot compression were analyzed. The results show that the temperature and strain rate have significant influences on the flow stress of 31%B₄Cp/6061Al composite, and the flow stress increases with decreasing temperature or with increasing strain rate. The optimum processing domains for 31%B₄Cp/6061Al composite are at temperatures of 480~525 ℃ with strain rates of 0.01~0.04 s^-1. However, the processing instability area is mainly concentrated in low temperature and high strain rate, and increases with the increase of strain. During the hot compressing, the microstructure evolution is influenced by hot processing parameters, such as the strain, temperature and strain rate. The higher the strain is, the more serious the grain deformation is. With increasing deformation temperature or decreasing strain rate, the size of the dynamic recrystallization grain in matrix increases obviously.