Enhanced mechanical properties of molybdenum-coated aluminium via laser cladding

High-quality molybdenum coating has been successfully deposited on the pure aluminium substrate by high-velocity oxygen fuel spraying and subsequent laser remelting and laser cladding process. The microstructure, bonding strength, micro-hardness and wear resistance of the coating were systematically investigated. Results showed that the obtained coating exhibits a good metallurgical bonding interface as well as a dense microstructure with Al8Mo3, AlMo3 and Al5Mo phases, which results in the significant improvement of the mechanical properties of the coating. The bonding strength is increased from 11 +/- 1 to 57 +/- 4 MPa after laser treatment. Micro-hardness of the coating (480 +/- 30 HV) is observed to be increased by about 70% in comparison with the as-sprayed coating (281 +/- 8 HV). The wear resistance of the Mo coating was also increased about five to six times by the laser remelting and cladding process.