TiAl基合金在置氢退火过程中γ相120o<111>孪晶界形成机制研究

Investigation on the formation mechanism of 120o<111> twin boundaries in γ phase of a TiAl based alloy during annealing treatment in hydrogen atmosphere

摘要:

本文利用金相显微镜、扫描电镜、EBSD技术、透射电镜和X射线衍射研究了铸态和锻态Ti–46Al–2V–1Cr–0.3Ni合金退火过程中氢对γ相120o<111>孪晶界的影响规律。结果表明，氢可以促进铸态和锻态合金γ相的静态再结晶，并且再结晶程度随氢含量的增加而增大；大量再结晶晶粒具有120o<111> 孪晶界，并揭示了120o<111> 孪晶界含量与氢含量的关系。氢致120o<111> 孪晶界增多的原因是氢减弱了γ相的弹性各向异性。

Abstract:

The effect of hydrogen on 120o<111> twin boundaries in γ phase of an as-cast and as-forged Ti–46Al–2V–1Cr–0.3Ni alloy was investigated by means of annealing treatment in hydrogen atmosphere, and the microstructure was observed by an optical microscopy, a scanning electron microscopy, an electron back scattered diffraction technique, a transmission electron microscopy and a X-ray diffraction apparatus. The results showed that hydrogen could promote γ-phase static recrystallization of the as-cast and as-forged alloy, and the extent of static recrystallization increased with increasing hydrogen content. Many static recrystallization grains possessed 120o<111> twin boundaries. The relationship between the fraction of 120o<111> twin boundaries and hydrogen content was given. Hydrogen-weakened γ-phase elastic anisotropy increased 120o<111> twin boundaries.