一种近β型钛合金Ti12LC热变形过程的微观组织研究

Research on Microstructure of Near β Titanium Ti12LC Titanium Alloy in Hot Deformation Process

对一种近β型的两相钛合金Ti12LC进行了热变形实验研究。采用差热实验分析了该合金的相变点温度。通过热模拟压缩实验,研究了变形温度、应变速率和变形量对该合金微观组织的影响。结果表明,随着温度的变化,初生α相的形态和数量发生改变,当上升到相变温度点以上时,β晶粒的粗化明显;随着应变速率的降低,合金内部动态再结晶充分,晶粒均匀细小,但过低的应变速率又会引起组织粗大;随着变形量的增加,条状α相含量相对增多,组织球化明显,且针状β转变组织含量减少,组织相对更加均匀;在变形量小于75%且不发生变形失稳的缺陷下,通过更大的变形量能获得更好的微观组织。

The thermal deformation tests of near-β titanium alloy Ti12 LC were carried out. The phase transition temperature of the alloy was obtained by DTA test. The influence of deformation parameters on the microstructure of the alloy was studied by thermal simulation compression test. The results show that with the change of temperature, the morphology and quantity of the primary α phase change, when it rises above the transition temperature, the coarsening of βgrain is obvious. With the increase of the strain rate, the full dynamic recrystallization in the alloy is sufficient, the grain is uniform and fine. But too low strain rate can cause the coarsening of the microstructure. With the increase of the deformation amount, the number of strip α phase increases, the spherification of the microstructure is obvious and the content of acicular βtransformed phase reduces. When the deformation amount is less than 75% and no deformation instability occurrs, the better microstructure can be achieved by larger deformation amount.