Yu Huijun, Meng Xiaoxi, Wang Zifan, Chen Chuanzhong
Key Laboratory of High Efficiency and Clean Mechanical Manufacture, Ministry of Education, and National Demonstration Center for Experimental Mechanical Engineering Education, School of Mechanical Engineering, Shandong University, Jinan 250061, China.
Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, and Shandong Engineering & Technology Research Center for Superhard Material, School of Materials Science and Engineering, Shandong University, Jinan 250061, China.
Materials (Basel). 2022 Aug 24;15(17):5819. doi: 10.3390/ma15175819.
Laser alloying has attracted significant attentions due to the advantages of high processing precision, good controllability and low heat effects on the substrate. However, the complexity of laser alloying requires further attentions on its processing parameters. This study aims at improving the wear resistance of the Ti-6Al-4V substrate by means of laser surface alloying with Ni-coated graphite (G@Ni). The effect of laser scanning speed is explored. The result suggests that the coating has a high surface quality and excellent metallurgical bonding with the substrate. NiTi and NiTi have a eutectic microstructure as well as in the TiC ceramic-reinforced phase as dendrites distribute in the γ-Ni matrix of the coatings. At higher scanning speeds, the lower energy density and shorter existence time of the molten pool refines the microstructure of the coating, improving its microhardness. At the scanning speed of 15 mm/s, the coating has the lowest wear weight loss due to its high microhardness and dense structure. This paper explores the influence of scanning speed on the microstructure and properties of the coatings, expanding the application of laser alloying on the surface modification of Ti-6Al-4V alloys.
激光合金化因其加工精度高、可控性好以及对基体的热影响低等优点而备受关注。然而，激光合金化的复杂性要求对其加工参数给予进一步关注。本研究旨在通过用镀镍石墨（G@Ni）进行激光表面合金化来提高Ti-6Al-4V基体的耐磨性。探讨了激光扫描速度的影响。结果表明，涂层具有较高的表面质量且与基体具有优异的冶金结合。NiTi和NiTi具有共晶微观结构，以及在涂层的γ-Ni基体中呈枝晶分布的TiC陶瓷增强相。在较高的扫描速度下，熔池的能量密度较低且存在时间较短，这细化了涂层的微观结构，提高了其显微硬度。在15 mm/s的扫描速度下，涂层因其高显微硬度和致密结构而具有最低的磨损失重。本文探讨了扫描速度对涂层微观结构和性能的影响，拓展了激光合金化在Ti-6Al-4V合金表面改性方面的应用。
