TB8钛合金表面间歇式真空渗氮层的组织与性能

Microstructure and Properties of Intermittent Vacuum Nitrided Layer on TB8 Titanium Alloy Surface

对TB8钛合金进行800℃间歇式真空渗氮6 h,研究了表面渗氮层的组织、硬度、耐磨性能及耐腐蚀性能。结果表明:TB8钛合金表面间歇式真空渗氮层主要由厚度60~80μm氮化物层和厚度110~130μm氮扩散区组成,表层物相包括TiN、TiN_(0.3)、Ti_(2)AlN及α-Ti,表层硬度为800~850 HV,由表层至心部硬度缓慢降低,心部基体的硬度为250~270 HV;在相同条件下,间歇式真空渗氮处理合金的磨损质量损失为未渗氮合金的1/12,表面形成了浅而窄的磨痕,耐磨性得到显著提高;间歇式真空渗氮处理合金在HF和HNO_(3)混合溶液中的腐蚀速率仅为未渗氮合金的1/153,表面未见明显腐蚀坑,耐腐蚀性能得到明显提高。

TB8 titanium alloy was treated by intermittent vacuum nitriding at 800℃for 6 h,and microstructure,hardness,wear and corrosion resistance of surface nitriding layer were studied.The results show that the surface inter mittent vacuum nitrided layer of TB8 titanium alloy was mainly composed of nitride layer with thickness of 60-80μm and nitrogen diffusion zone with thickness of 110-130μm,and the phases of surface layer were mainly composed of TiN,TiN_(0.3),Ti_(2)AlN and α-Ti.The surface layer hardness reached 800-850 HV and decrease slowly from the surface layer to the center,and the center matrix hardness was 250-270 HV.Under the same condition,the wear loss weight of alloy treated by intermittent vacuum nitriding was only 1/12 of that of the untreated alloy,shallow and narrow wear traces were formed on the surface,and the wear resistance significantly increased.The corrosion rate of alloy treated by intermittent vacuum nitriding in mixture of HF and HNO_(3) was about 1/153 of that of the untreated alloy,the obvious corrosion pit was not found on the surface,and the corrosion resistance greatly increased.