关键词: 轻质合金, Ti-22Al-25Nb合金, 热压缩, 微观组织, 织构

Abstract: Combining EBSD and SEM analysis, the flow behavior, microstructural evolution, and texture formation of the Ti-22Al-25Nb alloy under various hot compression conditions (temperature 940-1040 ℃, strain rate 0.01-1 s^-1, and reduction 20%-60%) were investigated. The results show that the flow stress is mainly influenced by both the temperature and strain rate. Specifically, increasing the temperature results in a decrease in peak stress. As the strain rate increases, the main softening mechanism shifts from dynamic recovery to dynamic recrystallization. At high strain rates (1 s^-1), formation of recrystallized grains along grain boundaries is observed. The microstructure analysis indicates that the microstructure after hot compression is predominantly in the B2 phase, with some trace precipitation of the O phase along grain boundaries at temperatures of 940 ℃ and 970 ℃. The texture evolution studies show that the predominant textures after deformation are {100}//RD and {111}//RD surface textures. Their relative intensities are influenced by the temperature, reduction, and strain rate. Notably, the proportion of the {111} texture increases with decreasing temperature, decreasing reduction, and increasing strain rate.

Key words: lightweight alloy, Ti-22Al-25Nb alloy, hot compression, microstructure, texture