高速钢表面TiN薄膜的界面疲劳剥落行为

Interfacial Fatigue Spalling Behavior of TiN Films on High Speed Steel

采用多弧离子镀技术在M2高速钢(W6Mo5Cr4V2)表面制备TiN薄膜,利用滚动接触疲劳法对薄膜界面疲劳行为开展研究。结果表明,界面疲劳失效主要表现形式为薄膜剥落,疲劳裂纹最先萌生于膜/基界面,经一定周次后向薄膜表面偏折,最终造成薄膜剥落。界面最大剪切应力幅(Δτ_(inter))是控制界面裂纹萌生和扩展的主要力学参量,通过Δτinter和临界疲劳周次(N)构建的评价模型可有效用于薄膜界面疲劳性能表征和寿命预估。界面疲劳性能与膜/基界面状态密切相关,利用Δτ_(inter)-N评价模型可有效辨别界面状态间的差异,采用辉光清洗或预制金属打底层等预处理方式均能有效提升界面抗疲劳剥落性能。选取薄膜剥落面积比为5%和50%,以及失效概率为30%、60%和90%比较发现,薄膜剥落面积比和失效概率值大小的选取不影响膜/基界面疲劳性能的判定。研究结果为镀膜轴承等零部件的疲劳性能表征和寿命预估提供了重要理论参考。

Performance and fatigue life of coating parts are seriously restricted by their interfacial fatigue property.Herein,TiN films were deposited on W6Mo5Cr4V2 steel substrates by multiarc ion plating.The interfacial fatigue failure mechanisms were studied by the rolling contact fatigue method.The results show that the interfacial fatigue failure mode is mainly film spalling.The fatigue cracks generated initially at the film/substrate interface proceed to the surface,resulting in film spalling.The interfacial maximum shear stress amplitude(Δτ_(inter))is a key factor for controlling interfacial crack initiation and propagation.The evolution model built using Δτ_(inter) and critical cycles(N)can be used to determine interfacial fatigue performance and for life forecast.The interfacial fatigue property is determined using a film/substrate interface,and glow discharge cleaning and prefabricated metal layer before coating deposition can improve interface fatigue performance.The evaluation model based on Δτ_(inter)-N curves can effectively used to identify the differences in interface states.Selection of the film-spalling area ratios of 5%and 50%and failure probabilities of 30%,60%,and 90%have little effect on the determination of film/substrate interfacial fatigue performance.The results provide important theoretical references for fatigue performance determination and lifespan prediction of coated bearings and other parts.