用扫描电镜和X射线衍射方法研究了DZ4合金喷丸试样在不完全固溶和固溶热处理过程中的再结晶行为. 在保温2 h条件下, DZ4镍基高温合金喷丸层在1000℃可发生再结晶; 在不完全固溶热处理中, 再结晶以胞状形式发生; 在固溶热处理中,再结晶以晶粒形式发生;γ'相对再结晶晶界迁移具有阻碍作用; 再结晶速率和再结晶层厚度主要取决于热处理温度, 保温时间影响不显著. 拉伸试样的金相观察表明, DZ4合金在1220℃保温2 h条件下再结晶的临界变形大约为0.9%; 再结晶晶粒优先在拉伸试样表面形核.
Abstract In this paper, the recrystallization of the surface deformed structure of DZ4 directionally solidified superalloy was studied by SEM and X-ray diffraction. The results show that under the condition of two-hour holding, recrystallization takes place at 1000℃.The recrystallization layer increases slowly with the temperature rise when the heat treatment is performed at the temperature lower than that of the -solutioning, whose structure is cellular one, but increases rapidly when performed at the temperature higher than that of the -solutioning and the larger phase within the recrystallization layer decreases until totally disappeared. The recrystallization formed at temperature of 950℃ and 870℃ for long holding time is cellular structure. The rate and thickness of recrystallization mainly depend on temperature, which have little relation to holding time.
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