激光熔覆制备颗粒增强Ni基复合涂层的组织结构

Microstructure of particle reinforced Ni-base alloy composite coating by laser cladding

关键词:  激光熔覆  颗粒增强  涂层  显微组织

Key words:  laser cladding  particle reinforced  coating  micro-structure

摘要:

利用横流CO₂激光器在45钢表面制备出原位自生TiB₂陶瓷颗粒增强Ni基复合材料涂层。XRD分析表明,涂层中存在γ-(Ni,Fe)固溶体及TiB₂为主的陶瓷相。利用SEM、EDS、EPMA对涂层微区组织结构进行研究。结果表明,涂层内枝晶组织细小均匀,枝晶内和枝晶间存在明显的组织和成分差异。热影响区是以混合马氏体为主的组织。涂层显微硬度比基体显著提高。

Abstract:

In-situ synthesis of TiB₂ ceramic particle reinforced Ni-base alloy composite coating has been conducted on 45 steel surface by CO₂ flow transverse laser.X-ray diffraction analysis shows γ-(Ni,Fe) solid-solution and ceramic phase mainly of TiB₂ in the coating.Scanning electron microscope,energy dispersive spectroscopy and electron probe microanalysis show that the dendrites dispersed homogeneously in the coating are very thin.The mierostructure and composition in the dendrites are evidently different from that in the intergranular.The mierostructure in the heat-affected zone is mainly composed of blended martensite.The microhardness of the coating increases substantially compared to that of the matrix.