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利用扫描电镜和透射电镜对热挤压态和退火态FGH98合金的相析出规律及组织特征进行了分析,并对其再结晶机制进行了深入研究.结果表明:热挤压态FGH98合金在空冷过程中已经发生了少量的再结晶现象,随着挤压温度的提高,体系内位错密度下降.退火态FGH98合金中再结晶机制主要与体系内未回溶的一次γ’相有关,在一次γ’相聚集区再结晶主要以依靠亚晶的聚合和亚晶的长大,或两者的混合机制进行形核;随着一次γ’相的减少,合金还可以通过应变诱发晶界迁移、多晶粒交汇区形核、孪晶叠加等多种方式形核.需要指出的是,FGH98合金中未回溶的一次γ’相在退火处理过程中也会通过部分的回复和再结晶发生软化效应.
The phase precipitation regularity and microstructure of hot extruded and annealed FGH98 alloy were analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and the recrystallization mechanism was further studied.The results show that the hot extrusion FGH98 alloy has better performance in air cooling A small amount of recrystallization has occurred and the dislocation density decreases with the increase of extrusion temperature.The recrystallization mechanism in FGH98 alloy is mainly related to the primary γ ’ ’Phase agglomeration recrystallization relies mainly on subgrain polymerization and subgrain growth, or a combination of both nucleation; with a γ’ phase reduction, the alloy can also be induced by strain-induced grain boundary migration, and more Grain nucleation, twin superposition and other means of nucleation.It should be pointed out that, FGH98 alloy unwetted primary γ ’phase in the annealing process will also be part of the recovery and recrystallization softening effect .