Chinese Journal of Lasers, Volume. 37, Issue 8, 2116(2010)
Yuan Qinglong,Feng Xudong,Cao Jingjing,Su Zhijun
Ni60 alloy coatings are prepared on the soft steel (Q235) surface by using a CO2 laser. Cross-section microstructure characteristics of the coating are studied by using scanning electronic microscope,energy spectrum,and micro-hardness analysis. The results show that the microstructure of Ni60 coating by laser cladding is typical rapid solidification structure. The morphology at the bottom of the cladding layer is a cell structure,whose growth is perpendicular to the interface of cladding and substrate. The morphology at the central and top zones of the layer is dendritic structure. The crystal grain of central zone grows with a single direction,but that of the surface layer grows with random direction. There are a large number of eutectic compounds at the middle of the dendrite. The black area contains a large number of inter-metallic compounds,such as alloy cementite. With the effects of solid solution strengthening,dispersion strengthening,hard phase strengthening,and fine grain strengthening,the hardness of the cladding layer is obviously greater than that of the substrate,which achieves the goal of hardening surface.
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Yuan Qinglong, Feng Xudong, Cao Jingjing, Su Zhijun. Yuan Qinglong,Feng Xudong,Cao Jingjing,Su Zhijun[J]. Chinese Journal of Lasers, 2010, 37(8): 2116
Category: laser manufacturing
Received: Nov. 10, 2009
Accepted: --
Published Online: Aug. 13, 2010
The Author Email: Qinglong Yuan (yqinglong@hpu.edu.cn)