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利用热模拟技术、金相观察及透射电子显微技术,对Fe-40Ni-Ti奥氏体模型合金850℃变形后等温松弛过程中的应力松弛曲线、微观组织及亚结构演化进行了分析。结果表明:试验合金的应力在松弛过程中各个阶段均高于无Ti的模型合金。松弛200 s时,观察到有再结晶发生;松弛1000 s时晶界周边出现大量的再结晶小颗粒。同时,松弛过程中位错由混乱的状态向多边形结构改变,松弛1000 s时出现完整的位错胞,未溶解的Ti N析出质点在一定程度上阻碍了再结晶的发生。
The stress relaxation curves, microstructure and substructure evolution of the Fe-40Ni-Ti austenitic alloy after 850 ℃ deformation were analyzed by means of thermal simulation, metallographic observation and transmission electron microscopy. The results show that the stress of the test alloy during each stage of relaxation is higher than that of the model alloy without Ti. When relaxation was 200 s, recrystallization was observed. A large amount of recrystallized small particles appeared around the grain boundaries after 1000 s relaxation. At the same time, the dislocations changed from disordered state to polygonal structure in relaxation process, and complete dislocation cells appeared after 1000 s relaxation. Undissolved TiN precipitates particles to a certain extent impeded the recrystallization.