Abstract:
Mixed powders of aluminum, titanium, TiB
2 with mass ratio of 1.0:3.0:0.5 were cladded on surface of AZ31 magnesium alloy by using a high energy laser with different powers (2.5, 3.0 kW). The microstructure, phase composition, hardness and corrosion resistance of the cladding layer were studied. The results show that during the laser cladding, the aluminum reacted with the titanium to form Al
3Ti phase. Meanwhile, the aluminum reacted with the magnesium to form Al
0.56Mg
0.44 phase and Al
12Mg
17 phase at the laser powers of 2.5 kW and 3.0 kW, respectively. The TiB
2 retained the original crystal structure. The cladding layer had a finer Al
3Ti phase at the laser power of 3.0 kW than at the laser power of 2.5 kW, and showed a better metallurgical bonding by the formation of a eutectic structure layer between the cladding layer and the magnesium alloy substrate. The laser power had little influence on the hardness of the cladding layer; the hardness increased and then decreased with the distance to the surface increasing. The laser cladding can effectively improve the corrosion resistance of AZ31 magnesium alloy. The corrosion resistance of the cladding layer at the laser power of 3.0 kW was better than that at the laser power of 2.5 kW.