激光熔覆碳化钛增强钛基复合涂层研究进展

钛合金具有密度低、比强度高、耐腐蚀性强等显著优点，在航空航天、海洋工程等领域具有广阔的应用前景。然而，钛合金硬度低、耐磨性差，严重制约其在摩擦工况下的使用寿命。激光熔覆技术具有生产效率高、热影响区窄、结合强度高、组织致密等优势，被广泛用于钛合金零部件表面改性和熔覆修复。高硬、高模量碳化钛的热物性参数与钛合金基材相近，常被选作激光熔覆钛基复合涂层的增强相，以提高其耐磨性。介绍了碳化钛的晶体结构、生长形态和性能特点。综述了碳化钛增强钛基激光熔覆材料体系以及工艺参数对熔覆层成形质量、宏观形貌和微观组织的影响。重点从碳化钛增强相的分布、数量、尺度以及相结构等方面，论述了碳化钛增强钛基激光熔覆层的组织特征，同时阐述了碳化钛强化机制，讨论了碳化钛增强钛基激光熔覆层组织特征与耐磨性能的内在关联性。最后提出了目前激光熔覆碳化钛增强钛基复合涂层研究中存在的问题与展望。

Research Progress of Laser Cladding Titanium Carbide Reinforced Titanium-based Composite Coating

Due to low density, high specific strength, strong corrosion resistance, etc., titanium alloy has wide application prospect in various fields such as aerospace, marine engineering, etc. However, the low hardness and poor wear resistance of titanium alloy severely restrict its service life under friction conditions. Laser cladding technology has the advantages of high production efficiency, narrow heat-affected zone, high bonding strength and dense microstructure and now is increasingly applied in surface modification and cladding repair of titanium alloy components. Titanium carbide with high hardness and modulus is generally selected as the reinforcement phase of laser cladding titanium-based composite coating to improve wear resistance, which is due to the similar thermal physical parameters of titanium carbide and titanium alloy substrate. The characteristics of crystal structure, growth morphology and performance of titanium carbide were introduced firstly. Then, the titanium carbide reinforced titanium-based material system was overviewed and the influences of the process parameters on the forming quality, macroscopic morphology and microstructure of the cladding layer were summarized. After that, the microstructure characteristics of titanium carbide reinforced titanium-based laser cladding layer were discussed from the distribution, quantity, size and phase structure of titanium c titanium carbide reinforcing phase and the strengthening mechanism was also revealed. The relationship between the microstructure characteristics and wear resistance of titanium carbide reinforced titanium-based laser cladding layer was discussed. Finally the existing problems and future development of laser cladding titanium carbide reinforced titanium-based composite coating were put forward.