The effect of powder composition on the morphology of in situ TiC composite coating deposited by Laser-Assisted Powder Deposition (LAPD)

In this paper, the effect of powder composition on in situ TiC formation within an Fe-based matrix coating during laser cladding was studied. Different atomic ratios of C:Ti (45% and 55%) were selected in order to adjust the matrix from an FeTi-based composition to an FeC-based one. Fe percentages of 70, 60, 50 and 10wt% were explored to increase the volume fraction of TiC in the clad. Results showed that chemical composition affects the TiC morphology as well as the TiC distribution and hardness profile in the clad. By increasing the C:Ti ratio from 45at% to 55at%, the volume fraction of the formed TiC increases. A higher volume fraction of TiC in the clad resulted in increases clad hardness. SEM and EDS analyses were used to characterize the phases in the clad, while increasing the C ratio promoted the formation of excess graphite in the Fe matrix.