Ti-6Al-4V合金高温氧化行为及显微组织研究

分析了Ti-6Al-4V合金在900 _oC,930 _oC,960 _oC温度下的氧化行为及表层显微组织变化。在0.5-24 h时间内,氧化层不断增厚,越靠近表面氧化层越疏松。氧含量在氧化层/富氧层界面的5 μm内发生急剧下降,进入富氧层后缓慢下降直到稳定。氧化层中以TiO₂为主,同时也出现了Al₂O₃。富氧层中的a相含量远远高于基体内部,其晶粒尺寸也发生长大。富氧层深度与热暴露时间的关系可用对数函数描述,通过线性回归分析计算出了O在富氧层中的扩散激活能为206 kJ/mol。

High-temperature oxidation behavior and microstructure evolution of Ti-6Al-4V

This paper investigates the oxidation behavior and microstructure evolution of Ti-6Al-4V alloy at 900_oC, 930_oC and 960_oC. The thickness of surface oxide layer increases during 0.5-24h and the closer to the surface, the more porous of the oxide. There is a sharp decrease of O level at the boundary of oxide layer and a-case. The O level decreases gradually inside the a-case to a stable level in the Ti-6Al-4V base material. The oxide layer is maily composed of TiO₂, and there is also small amount of Al₂O₃. The volume fraction of a in much higher in the a-case and the grain size is also larger. The relationship between a-case depth and thermal exposure time can be fitted using log-log function. Linear regression analysis shows that the activation energy of O diffision in a case is 206 kJ/mol.