TC4表面激光熔覆Ti-Al-N复合涂层的组织与性能

Microstructure and properties of laser cladding Ti-Al-N composite coating on TC4 surface

为了在TC4钛合金表面开发新型MAX相复合涂层,利用激光熔覆在TC4钛合金表面原位合成了含Ti_(2)AlN MAX相的Ti-Al-N复合涂层,分析了涂层的组织结构特征及硬度分布,研究了复合涂层的原位合成机理。结果表明,不同物质的量比粉体熔覆后的涂层与基体呈现良好的冶金结合,涂层由TiAl基体、Ti_(2)AlN MAX相和TiN树枝晶组成,涂层平均硬度约为基体的2倍以上,涂层厚度在1mm~1.6mm之间;添加少量Al粉能够促进熔池中TiN和TiAl的反应,从而显著提高了涂层中Ti_(2)AlN MAX相的含量。此研究结果在明晰MAX相原位合成机理的基础上,对采用激光熔覆技术制备MAX相复合涂层具有重要意义。

In order to develop a new MAX phase composite coating on the surface of TC4 titanium alloy,a Ti-Al-N composite coating containing Ti_(2)AlN MAX phase was synthesized on the surface of TC4 titanium alloy by laser cladding.The structure characteristics and hardness distribution of the coating were analyzed,and the in-situ synthesis mechanism of the composite coating was studied.The results indicate that the coating and the substrate after powder cladding with different ratios of amount of substance show a good metallurgical bond.The coating is mainly composed of TiAl matrix,Ti_(2)AlN MAX phase,and TiN dendrites.The average hardness of the coating is about twice that of the substrate.The coating thickness is between 1mm~1.6mm.Adding a small amount of Al powder can promote the reaction of TiN and TiAl in the molten pool,thereby significantly increasing the content of Ti_(2)AlN MAX phase in the coating.The research results are of great significance to the preparation of MAX phase composite coatings by laser cladding technology based on the clarification of the MAX phase in-situ synthesis mechanism.