Ti600高温钛合金600℃下表面稳定性研究

Research on Surface Stability of Ti600 High-Temperature Titanium Alloy at 600 ℃

对Ti600合金600℃下氧化特性和氧化对力学性能的影响进行了研究。结果表明,Ti600合金氧化皮生长接近氧扩散控制的氧化皮生长规律。经过600℃长时间氧化,表面主要形成TiO2和Al2O3氧化物,固溶于α-Ti的氧元素主要存在于八面体间隙中,使得α-Ti晶格a、b轴几乎不变,c轴畸变明显。通过力学性能对比分析,证明表面氧化是Ti600合金热暴露后塑性降低的最主要原因,要使合金在600℃稳定使用,采取表面保护措施是必要的。

The oxidation characteristics and the effect of oxidation on mechanical properties of Ti600 alloy at 600 ℃ were researched.The results show that the increase of oxide skin is nearly controlled by the diffusion of O element.After 600 ℃ thermal exposure for a long time,the surface is mainly composed of TiO2 and Al2O3.The solution O element mainly exists inside octahedral interstice,which leads to almost changeless ＂a＂ and ＂b＂ and obviously increased ＂c＂ of hcp α-Ti crystal lattice.Through the comparison of mechanical properties between the samples with oxide skin and without oxide skin,it can be concluded that the decrease of plasticity is mainly due to the oxidation of the alloy.Thus it is very necessary to adopt surface protection for Ti600 alloy for 600 ℃ application.