钛合金表面的热氧化层工艺及性能

Process and Properties of Thermal Oxidation Layer on Surface of Titanium Alloy

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。经790℃真空扩散后,表面氧化层中的部分TiO2发生了分解,在表面与基体之间沿层深方向产生了一定的硬度梯度。热氧化后进行真空扩散的工艺可有效地降低Ti 6Al 4V合金与GCr15钢在空气和真空中的干摩擦系数,提高Ti 6Al 4V合金在空气和真空中的磨损抗力。

A hardened layer possessing good bonding strength with substrate was prepared on the surface of Ti6Al4V alloy using a process of thermal oxidation followed by diffusion in vacuum. The friction and wear tests were carried out under the air and vacuum conditions. The results showed that the hardened layer with a thickness of 30μm consisted of a thin surface oxide layer and an oxygen diffusion zone. After diffusion in vacuum at 790℃, partial TiO2 was decomposed,resulting in formation of a certain microhardness gradient between surface and substrate. The coefficient of the dry friction of thermal oxidation/vacuum diffusion treated Ti6Al4V alloy against GCr15 steel was efficiently reduced in air and vacuum. The wear resistance of the treated Ti6Al4V alloy was significantly increased in air and vacuum.