Ti-6Al-4V合金表面的热氧化/真空扩散处理

Thermal oxidation/vacuum diffusion treatment on surface of titan ium alloy

利用热氧化后真空扩散处理工艺在Ti 6Al 4V合金表面制备了与基体结合良好的硬化层 ,并在空气和真空条件下分别进行了摩擦磨损试验。结果表明 ,硬化层由表面氧化物薄层和氧扩散区组成 ,硬化深度可达 6 0μm。经 84 0℃真空扩散后 ,在表面硬化层中发现有Ti3 Al相形成 ,使沿层深方向的硬度下降趋势变缓。热氧化 /真空扩散处理可有效地降低在空气和真空中的Ti 6Al 4V合金与GCr15钢的干摩擦因数 ,提高Ti 6Al

A hardened layer possessing good bonding strength wit h substrate was prepared on the surface of Ti-6Al-4V alloy by a process of therm al oxidation followed by vacuum diffusion. The friction and wear tests were carr ied out under the air and vacuum conditions. The results show that the hardened layer, which thickness can reach 60 μm, comprises a thin surface oxide layer a nd an oxygen diffusion zone. After vacuum diffusion at 840 ℃, it is found that the decrease rate of the hardness is slower with increasing the depth within th e diffusion layer, resulting from the formation of the Ti 3Al phase. The coef ficient of the dry friction of the thermal oxidation/vacuum diffusion treated Ti -6Al-4V alloy against GCr15 steel is efficiently reduced. The wear resistance of the treated Ti-6Al-4V alloy is significantly increased.