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研究了Ti 48Al合金全片层组织在 115 0℃时效时的组织稳定性。结果表明 ,140 0℃ ,1h固溶处理后炉冷获得的粗片层组织的稳定性远远优于空冷获得的细片层组织。细片层组织首先在晶界处发生不连续粗化 ,而后粗化片层组织中的α2 相发生溶解并球化 ,从而转变为近γ组织 ;空冷组织中魏氏片层的存在降低了片层组织的稳定性 ,魏氏片层 /基体界面与晶界一同成为片层组织发生分解的起始部位。Ti 48Al+ 0 .8%B(摩尔分数 )合金的细片层组织因晶界TiB2 相的存在有效抑制了晶界不连续粗化 ,但γ相从TiB2 /基体界面和晶界重新形核生长使片层组织转变为均匀的细晶近γ组织
The microstructures and mechanical properties of Ti48Al alloy were studied at 115 ℃ for aging. The results show that the microstructure of the coarse lamella obtained after the solution heat treatment at 140 ℃ for 1h is much better than the thin lamella microstructure obtained by air cooling. The microstructure of fine lamellar layer is discontinuous roughening first at the grain boundaries, and then the α2 phase in the coarsening lamellae is dissolved and spheroidized, which transforms to near-γ microstructure. The presence of Wei’s lamella in the air- The stability of the layer organization, Wei’s sheet / matrix interface together with the grain boundaries become the starting point for the decomposition of lamellar tissue. The microstructure of Ti48Al + 0.8% B (mol fraction) alloy effectively restrained the grain boundary discontinuous coarsening due to the presence of TiB2 phase, but the γ phase recrystallizes from TiB2 / matrix interface and grain boundary Layered tissue into uniform fine grain near γ tissue