Laser (Nd:YAG) cladding of AZ91D magnesium alloys with Al+Si+Al2O3

• Published in: Journal of alloys and compounds 2006-01, Vol.407 (1-2), p.201-207
• Main Authors: YAO JUN, SUN, G. P, WANG, Hong-Ying, JIA, S. Q, JIA, S. S
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Metallic coatings; Metals. Metallurgy; Production techniques; Surface treatment
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2005.06.049

Magnesium alloys, although attractive as lightweight materials, have some undesirable properties including poor corrosion resistance and poor creep resistance. The laser surface cladding of AZ91D magnesium alloy with Al+Si+Al2O3 powders (in the wt.% ratio of 7:1:2) was investigated. Laser processing was carried out with a 5 kW Nd:YAG laser. The microstructure and phase analyses of the surface cladding layer were carried out; furthermore, the morphology of the cladding zone, volume fraction and distribution of the Si and Al2O3 particles in the laser surface cladding layer were also investigated. The average microhardness of the surface layer was measured in detail as a function of laser parameters. Microhardness of the surface layer was significantly improved to as high as 210 HVO.05 as compared to 60-70 HVO,05 of the AZ9lD substrate, and the average microhardness of the cladding layer of the composite surfaced specimen decreases with increasing of laser power. However, the rate of decrease is faster at lower power. Though the average microhardness of the surface cladding layer remains constant, there is a little fluctuation in the reading in some regions possibly because of the random distribution of hard particles in the cladding layer. Finally, the proper processing parameter ranges for formation of a homogeneous microstructure and enhancement of microhardness for laser surface cladding of AZ91 D with Al + Si + Al2O3 were established.