氢处理对TC21合金显微组织的影响

Effect of Hydrogenation on Microstructure of TC21 Alloy

摘要:

利用XRD、OM和TEM研究两相钛合金TC21置氢前后以及除氢后的显微组织变化。研究发现：随着氢含量的增加，TC21合金中的β相逐渐增加，当氢含量达到0.319%（质量分数，下同）以上时，试样中出现面心立方的氢化物δ。氢化物主要是在高温置氢后冷却过程中通过扩散方式发生共析反应形成的。由于共析反应所造成的晶格畸变，除氢后发生了再结晶，晶粒组织更加细化。

关键词:钛合金;氢处理;氢化物;共析转变

Abstract:

Microstructure evolution of biphase TC21 alloy before and after hydrogenation as well as dehydrogenation was investigated by XRD, OM and TEM. The results show that the amount of β phase increases gradually as the hydrogen content increases; fcc δ hydrides appear when the hydrogen content reaches above 0.319%. Hydrides mainly precipitate by eutectoid transformation through diffusion during the cooling process after high-temperature hydrogenation. Because of the lattice distortion caused by eutectoid transformation, recrystallization occurs after the dehydrogenation, so the grains are refined and become much more homogenous.

Key words:titanium alloys; hydrogenation; hydride; eutectoid transformation