Laser Cladding Al-Si/Al2O3-TiO2 Composite Coatings on AZ31B Magnesium Alloy

• Published in: Journal of Wuhan University of Technology. Materials science edition 2012-12, Vol.27 (6), p.1042-1047
• Main Authors: Cui, Zeqin, Yang, Hongwei, Wang, Wenxian, Wu, Hongliang, Xu, Bingshe
• Format: Article
• Language: English
• Subjects: AZ31B镁合金; Chemistry and Materials Science; Materials Science; X-射线衍射; 复合涂层; 扫描电子显微镜; 激光熔覆; 激光表面改性; 激光表面熔覆; 耐磨损性
• ISSN: 1000-2413; 1993-0437
• DOI: 10.1007/s11595-012-0597-x

To improve the wear resistance and corrosion resistance of magnesium alloys, a 5 kW continuous wave CO2 laser was used to investigate the laser surface cladding on AZ31 B magnesium alloys with Al-Si/Al2O3-TiO2 composite powders. A detailed microstructure, chemical composition, and phase analysis of the composite coatings were studied by scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, and X-ray diffraction （XRD）. The laser cladding shows good metallurgical bonding with the substrate. The composite coatings are composed of Mgl7Al12, Al3Mg2, Mg2Si, Al2O3, and TiO2 phases. Compared to the average microhardness （50HV0.05） of the AZ3 1 B substrate, that of the composite coatings （230HV0.05） is improved significantly. The wear resistances of the surface layers were evaluated in detail. The results demonstrate that the wear resistances of the laser surface-modified samples are considerably improved compared to the substrate. It also show that the composite coatings exhibit better corrosion resistance than that of the substrate in 3.5wt% NaCI solution.