多尺度碳化物增强钴基复合材料的组织调控与耐磨机理

为了满足航空、航天、能源、医疗等领域对于高耐磨材料的需求，本项目利用粉末冶金方法，在CoCrW合金中引入微米级WC与Cr3C2颗粒，通过颗粒与基体合金发生元素作用，形成分布在晶界处的M6C和M32C6型碳化物，提高晶界强化效果；通过烧结与热处理参数控制，使CoCrW基体原位自生析出细小弥散的碳化物，提高摩擦磨损性能，从而获得高强高耐磨的多尺度碳化物增强钴基复合材料。基于结构参数、制备参数、热处理参数的设计和优化，实现多尺度(M6C+M32C6)/CoCrW复合材料的微观组织与耐磨性能的精确设计和调控，阐明基体中的合金元素与外加颗粒的作用机制，从而揭示内生碳化物与外加增强相相变机制与增强相/基体的界面形成机理，明确碳化物种类、形态、分布等微观组织参数与复合材料力学性能和耐磨性能的内在关联，为高耐磨CoCrW材料的结构设计和摩擦磨损机理的研究提供理论基础和试验指导。

In order to meet the demand for high wear-resisting material used in the areas such as aerospace, energy, medical etc. in this study, micrometer-scale WC and Cr3C2 particles were added into the Co-Cr-W alloy by the method of powder metallurgy. In this study, M6C and M32C6 carbides were formed at the grain boundary through elements interaction between the carbides and matrix alloy, which effectively improved the grain boundary strength. By controlling the parameters of heat sintering and heat treatment, finely dispersed carbides in situ precipitated in the Co-Cr-W matrix, which effectively improved the friction and wear resistance, thereby multi-scale carbide strengthened Co-base composites with high strength and wear resistance were obtained. Base on the design and optimization of the parameters of material--microstructure, preparation and heat treatment, precise design of microstructure and macro-control of comprehensive performance of multi-scale (M6C + M32C6)/Co-Cr-W composites were achieved and the interaction mechanism of alloy element in Co-Cr-W matrix and added particles was clarified, which revealed the transformation mechanism of endogenous and additional carbide reinforced phases and formation mechanism of interface between matrix and them. The effect of microstructure parameter (carbide types, appearance, distribution etc.) on the mechanical properties and wear resistance of the composites was studied. This research provides theoretical basis and application guidance for structure design of high wear-resisting Co-Cr-W material and the study of friction and wear mechanism.