BT20钛合金表面渗氧研究

Surface oxygen diffusion hardening of BT20 titanium alloy

氧与钛之间的亲合力比较高,利用这一点可以通过热处理的办法对钛及钛合金部件表面的硬度和耐磨性进行提高。将激光处理的和未经激光处理的BT20钛合金放置在一种特殊固体介质中于大气气氛下进行渗氧处理,来研究炉的加热条件和前处理过程对显微组织和硬度的影响。激光处理过的和未经激光处理的BT20钛合金在相同温度和处理时间的条件下进行渗氧以获得强化层。处理后外层为金红石型的TiO2,里层为由-αTi组成的氧固溶强化层。激光处理的试样在渗氧后表面硬度最高可达到Hv628,厚度可以达到35μm,而未经激光处理的钛合金的表面硬度最高可以达到Hv580,膜厚度达到25μm。

The high oxygen affinity of titanium can be used to improve the surface hardness and wear resistance of titanium and titanium alloy components by means of thermal treatments. In the present paper,a comparision of the effects of furnace process and pretreatment,carried out using air as treatment atmosphere in a special solid medium,on the microstructure and hardness of commerically BT20 titanium alloy samples is reported. The samples were treated in the form of the as-received and laser treated conditions. Both treatment types,performed at the same temperature and time, produce modified surface layers. The outer layer consists essentially of rutile TiO2 ,while the inner layer（oxygen-diffusion zone） consists of a-Ti. The thickness and hardness of the oxygen-diffusion zone formed on the laser treated sample can be amount to 35μm and Hv628, respectively. While the oxygen-diffusion zone obtained on as-received BT20 samples have a thickness of 25μm and hardness of Hv580.