Laser Surface Alloying of ZM5 Mg Alloy with Nano-SiC Powder
C-J. Chen, M. Zhang, Q-M. Chang, S-C. Zhang and H-Y. Ma
The aim of this work was to improve the surface layer of a cast Mg alloy (ZM5) by means of laser surface treatment; namely the laser surface alloying (LSA) of nano-SiC powder onto the ZM5 Mg alloy surface using a pulsed Nd:YAG laser. The microstructure, chemical composition and microhardness of the alloyed layer were determined using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis and microhardness testing, respectively. It was shown that laser surface alloying produced a relatively smooth, crack-free and hard surface layer. The interface between the alloyed layer and the substrate showed a good metallurgical joint. The hardness of the surface layer was increased significantly over the base ZM5 Mg alloy due to the formation of dispersive hard particles of SiC and the effect of refinement of the alloyed microstructure.
Keywords: Magnesium alloy, nano-SiC coating, laser surface alloying (LSA), microstructure, chemical composition, hardness