Laser cladding of electroplated Ni-WC on surface of TA2:microstructure and mechanical properties

The combination of electroplating Ni/WC composite coating and laser cladding was utilized to modify surface of TA2 substrate. Microstructure of the Ni/WC composite coating was characterized by SEM and TEM. The composite coating consists mostly of TiNi-WC layer and Ti2Ni layer. The phases in the TiNi-WC layer include TiNi, unreacted Ti and uniformly dispersed WC, while Ti2Ni is the main phase in the Ti2Ni layer. The composite coating shows remarkable nano-hardness (9.5 GPa) compared to the TA2 substrate (2.5 GPa), which is contributed by residual WC particles in the laser remelted coatings. In addition, the hard phase WC particles facilitates the wear resistance of the laser remelted Ni/WC coating. Abrasive wear and adhesive wear mechanism are dominant in the friction and wear mechanism.