TC4表面激光熔覆Ti-Al-(C, N)复合涂层的组织与力学性能  

Microstructure and Mechanical Properties of Laser Cladded Ti-Al-(C, N) Composite Coating on TC4 Surface

作　　者：冯进宇 肖华强[1] 肖易 游川川 赵欣鑫 田雨鑫 周璇 Feng Jinyu;Xiao Huaqiang;Xiao Yi;You Chuanchuan;Zhao Xinxin;Tian Yuxin;Zhou Xuan(College of Mechanical Engineering,Guizhou University,Guiyaug,Guizhou 550025,China)

机构地区：[1]贵州大学机械工程学院,贵州贵阳550025

出　　处：《中国激光》2022年第2期159-167,共9页Chinese Journal of Lasers

基　　金：国家自然科学基金(52065009);贵州省科技计划项目(黔科合基础-ZK[2021]一般269);贵阳市科技计划项目(筑科合同[2021]1-4号)。

摘　　要：为了改善TC4合金的表面性能,在TC4表面预置不同成分的复合粉末,采用激光熔覆工艺制备了Ti-Al-(C, N)复合涂层。通过对涂层的物相组成及微观组织结构进行分析,揭示了复合涂层的合成机理,并结合复合涂层的组织结构特征分析了其硬度分布。结果表明:熔覆层与基体之间形成了良好的冶金结合;熔覆层主要由基体相Ti_(x)Al_(y)和树枝晶TiC_(1-x)N_(x)组成;激光快速熔凝过程中Al元素扩散进入TiC_(1-x)N_(x)相枝晶边缘形成MAX相;合适的粉末配比能使熔覆层的组织细小致密,熔覆层的最高硬度为基体的2.04倍。Objective Titanium alloys have been widely used in various fields like aerospace, biomedicine, and marine, because of their low density, high specific strength, good corrosion resistance, and biological compatibility. However, titanium alloys’ inherent low hardness, poor wear resistance, and high-temperature oxidation limit their future applications. Surface modification using laser cladding technology can significantly improve titanium alloy’s shortcomings. Among the materials used in surface modification, the ternary cermet MAX phase has the excellent properties of metal and ceramic materials due to its unique lamellar structure and bonding type, making it a great candidate for use as a protective coating material. Therefore, starting from the powder system ratio, Ti-Al-(C, N) composite coating was synthesized in situ by laser cladding technology. The effects of powder ratio on the phase, structural properties, and hardness of the coating were thoroughly investigated.Methods The substrate used in this study was 40 mm×20 mm×10 mm TC4 alloy block. The cladding materials were Ti Al powder(particle size was 15-53 μm and purity was greater than 99%), Ti C powder(particle size was 2-4 μm and purity was greater than 99%), and Al N powder(particle size was about 1 μm and purity was greater than 99.9%). The three powders were mixed in the planetary mill(YXQM-4 L) using the preset ratio(Table 1). The ball-material ratio was 5∶1, the rotating speed was 200 r/min, and the milling time was 120 min. The mixed powder materials were pre-laid on TC4 with a thickness of about 2 mm by a self-made mold after being vacuum dried at 100 ℃ for 10 h. Laser cladding was carried out by the YSL-6000 fiber laser in an argon chamber with a flow rate of 10 L/min. The optimized cladding parameters were as follows: the spot size was 10 mm×2 mm, laser output power was 2.7 k W, and scanning speed was 120 mm/min. The microstructure, element distribution, and phase of the coatings were examined using a scanning electron microscope(SE

关 键 词：激光技术 激光熔覆 复合涂层 显微组织 合成机理 

分 类 号：TG174.4[金属学及工艺—金属表面处理] TG665[金属学及工艺—金属学]