Tribological Improvement of Titanium Alloys by Surface Engineering without Sacrificing their Fatigue Resistance

尽管钛合金具有高的强度质量比和良好的抗疲劳性和耐腐蚀性，但其摩擦学性能较差，这妨碍了其在航空航天和汽车部件中进行滑动接触。与其他具有类似静态和动态强度的材料相比，钛合金具有更高的磨损率，更高的摩擦系数，并且易于磨损和咬合。各种表面处理方法已被用来改善钛合金的磨损和摩擦性能。然而，它们引起机械性能的不可接受的变化，包括断裂韧性和疲劳强度的降低。未来五年的拟议研究将旨在改善低温离子氮化合金的微观结构和性能，这些合金是申请人之前的NSERC发现计划的一部分。提出了控制化合物层的成分和形貌以提高延展性、韧性和耐磨性的新方法。因此，所提出的研究的主题是：（A）通过以下预处理来增强低温离子渗氮处理：i）塑性变形引起的应变，ii）在表面上沉积钒并随后进行热扩散。(B)离子渗氮表面沉积类金刚石膜的双重表面处理的发展实验工作将通过开发磨损机制图和识别疲劳裂纹扩展机制来阐明微观结构与耐磨性和抗疲劳性之间的关系。这些调查将提供深入了解磨损和疲劳的微观机制，确保微观结构和机制之间的关系建立，这将有助于持久和实用的表面处理的发展。总的来说，这项研究将提供生产节能工程部件和技术所需的科学和工程知识，并培养两名博士，一名硕士生和一名本科生。2在这个项目中获得的独特的培训，知识和技能将使这些HQP对许多加拿大制造商非常有吸引力。这些专业人员将配备有宝贵的技能，可以满足加拿大在技术和汽车，航空航天部门以及其他工业应用的未来要求，他们将在这个行业的高需求。

Titanium alloys despite their high strength-to-mass ratios and good fatigue and corrosion resistance exhibit poor tribological performance that preclude their use in aerospace and automotive components subjected to sliding contact. Compared to other materials of similar static and dynamic strength, titanium alloys have higher wear rates, higher coefficients of friction, and they are prone to galling and seizure. Various surface treatment methods have been employed to improve the wear and frictional behaviour of titanium alloys. However, they cause unacceptable changes in mechanical properties including decreases in fracture toughness and fatigue strength. The proposed research in the next five years will be aimed at improving microstructures and properties of low temperature ion nitrided alloys developed as a part of the applicant's previous NSERC Discovery program. New methods are proposed to control compositions and morphologies of the compound layer to increase ductility, toughness and wear resistance Accordingly, the main themes of the proposed research are: (A) Enhancement of low temperature ion nitriding treatment by following pre-treatment i) plastic deformation induced strain, ii) deposition of Vanadium on surface followed by thermal diffusion. (B) Development of a duplex surface treatment by deposition of DLC coatings on ion nitrided surfaces The experimental work will elucidate relationships between microstructures and wear and fatigue resistance by developing wear mechanism maps and identifying fatigue crack growth mechanisms. These investigations will provide insight into the micromechanisms of wear and fatigue—ensuring that the relationship between the microstructure and the mechanisms are established, which will help with the development of durable and practical surface treatments. Overall, the research will provide the scientific and engineering knowledge needed to produce energy efficient engineering components and technologies and train two Ph.D., one MASc and one undergraduate student.The unique training, knowledge, and skills obtained in this program will make these HQP very attractive to many Canadian manufacturers. These professionals will be equipped with valuable skill sets that can meet Canada's future requirements in technology and the automotive, and aerospace sectors as well as other industrial applications where they will be in high demand in this industry.