多羟基介质下纳米晶化TiNi60合金重构表面的超滑行为与机制研究

In current project, a novel strategy in lubrication of Nitinol 60 alloy with polyhydroxy group lubricant is proposed. Herein, surface grain refinement and segregation of nickel in Nitinol 60 alloy are suggested to be realized with ultrasonic deep rolling enhancement and ion irradiation together. The nickel oxide solid like film with super low friction will be formed under the tribochemical reaction of nickel, polyhydroxyl group lubricant and oxygen. The results are beneficial to the application of Nitinol 60 alloy in aviation and space and establish the theoretical foundation for its application. At the same time, the influence of surface nanostructure, reconstruction and the structure of polyhydroxyl group lubricant on the superlubricity of Nitinol 60 alloy will be investigaeed. The mechanism of gain refinement, directed migration and tribochemical reaction of polyhydroxyl group lubricant will be illustrated. And the superlubricity of Nitinol 60 alloy will be realized. Furthermore, we will try to establish the superlubricity model considering the effects of nanocrystallization, surface reconstruction and tribochemical and obtain a new technology of surface treatment about Nitinol 60 alloy. The findings of the present project will be beneficial to improve the tribological perproties of Nitinol 60 alloy and promote the understanding of superlubricity. And it will further provide the technical support for high-speed rotating machinery and low power consumption, long life mechanical design. Thus the current subject has important academic value and application prospects.

本项目提出多羟基介质润滑TiNi60合金的新思路，采用超声深滚强化和离子辐照TiNi60合金，实现合金表面晶粒细化和镍原子表面偏聚摩擦表面，通过活性镍原子及多羟基介质的摩擦化学反应，获得超低摩擦羟基氧化镍复合类固体膜，为TiNi60合金高速轴承在航空、航天等领域的推广应用奠定理论基础。本项目将揭示纳米晶化、表面重构及多羟基介质本征结构对TiNi60合金超滑行为的影响规律。阐明TiNi60合金表面晶粒细化、定向迁移及多羟基介质下的界面摩擦化学反应机制，实现多羟基介质下TiNi60合金的超滑行为，建立包含纳米晶化、表面重构及摩擦化学效应的超滑模型，最终形成TiNi60合金超滑行为的处理新工艺。研究结果将进一步提升低密度高强度TiNi60合金的摩擦学性能，丰富人们对超滑行为的认识，并为现代高速旋转机械和低能耗、长寿命机械设计提供理论支撑，具有重要的学术意义和工程应用价值。

本项目采用超音速微粒轰击表面强化和激光辐照处理TiNi60合金，实现了合金表面晶粒细化和镍原子表面迁移摩擦面，通过活性镍原子及多羟基介质与摩擦界面的摩擦化学反应，获得了TiNi60合金的超滑行为并揭示了其超低摩擦机理。具体研究内容包括：研究了超音速微粒轰击表面强化TiNi60合金表面强化层的形成原理和激光辐照TiNi60合金中镍原子表面迁移摩擦面的形成机理，结果表明随功率、强化时间的增大，合金表面硬度、粗糙度增加，摩擦系数有所减少；摩擦磨损试验结果以及磨损表面形貌的显微分析表明TiNi60合金在摩擦过程中，在接触界面上形成一层摩擦化学反应膜；Raman光谱和XPS分析发现在摩擦过程中TiNi60合金表面形成了层状物质羟基氧化镍，而摩擦配副高速钢上形成了羟基氧化铁；从而获得了低至0.0005的超低摩擦系数；进而从实验和理论上揭示了蓖麻油润滑工况下TiNi60合金的摩擦化学反应以及TiNi60合金表面超滑行为控制规律，其超滑机理为极性高、碳链长蓖麻油在TiNi60合金表面形成了己酸插层的层状羟基氧化物末端带正电氢间的相互排斥力而获得了超低摩擦。本研究为现代航空发动机关键摩擦副滚动轴承和低能耗、长寿命机械设计提供理论支撑。