Studies on Hardfaced Overlay of Diamond Grits Reinforced Ni-Based Alloy Fabricated by Laser Cladding

In this work, a hardfaced overlay of diamond grits reinforced Ni-based alloy was attempted to fabricate on carbon steel by laser cladding technique. In order to obtain the optimal microstructures of hardfaced overlay, the different heat inputs were experimented by varying laser power and sweep speed. The results testify that the hardfaced overlay can be successfully obtained. SEM observation shows that most diamond grits are buried in the overlay, and a few is exposed on the surface. When laser energy density is ranged from 28.6 to 32.0 J/mm2, the diamond grits are wetted well and bonded tightly with Ni-based alloy. A consecutive compound layer is formed at the interface of diamond and Ni-based alloy. Raman spectra analysis indicates that the diamond grits suffer from thermal damages when the laser energy density is higher than 32.0 J/mm2.