细小等轴α相对Ti-55531合金静态再结晶行为的影响

Effect of Fine Equiaxed α Phase on Static Recrystallization Behavior of Ti-55531 Alloy

摘要:

初始等轴组织Ti-55531合金在相变点以上经过0.01、0.1、1 s~(-1)不同应变速率的等温压缩变形,随后进行750℃×5 min/AC热处理。采用扫描电子显微镜和透射电子显微镜研究了后续热处理时变形α相和基体β相的静态再结晶机理。结果表明,随着应变速率的升高,残留等轴α相的含量增加。变形合金中拉长α相在经过热处理后有球化现象,同时在强度相对较高的拉长α相端部的基体β相中,位错储能较高,有助于β相再结晶形核和空冷过程中局部高密度次生α相析出。

关键词:钛合金;α相;β相;再结晶

Abstract:

The initial equiaxed Ti-55531 alloy has been carried out the isothermal compression deformation with 0.01, 0.1 and 1 s~(-1) above the phase transformation point, and heat treatment at 750 ℃×5 min/AC. The scanning electron microscope and transmission electron microscope technologies were used to investigate the static recrystallization of deformed α and matrix β phases during subsequent heat treatment. The results show that the content of residual equiaxed α phase increase with the increase of strain rate. The spheroidization behavior of elongated α phase in the deformed alloy occurs after heat treatment. Meanwhile, the dislocation storage energy within β phase is large at the end of the elongated α phase with relative high strength, which facilitates the β recrystallization and nucleation and improved the local high-density secondary α-phase precipitation during air cooling.

Key words:titanium alloy;α phase;β phase;recrystallization