Microstructures and wear behaviors of WC particle reinforced nickel-based composites fabricated by selective laser melting

To improve the mechanical performance of popular Nickel alloys, in this study, selective laser melting method was introduced to print IN718 alloy composites (WC/IN718) by using Tungsten carbide (WC) as reinforcement particles. The effects of WC content (10-20 wt%) on microstructure evolution and mechanical performance of the printed composites were analyzed comprehensively. It was found, with proper addition of WC reinforcement particles, desired microstructures and mechanical properties can be achieved in the printed composites. WC particles could distribute uniformly in the matrix and excellent metallurgical bonding could be obtained at the heterogeneous interface between the WC_P and the IN718 matrix. Under strong laser irradiation, the surface of WC particles could be melted and the decomposed W and C atoms could diffuse into the matrix under strong laser irradiation. WC-W₂C/M_xC/IN718 (M representing Ni, Cr, Fe, Ti, Nb) sandwich structure was formed due to the substitution of matrix element for W and C element in WC particles. When the added WC particle content increases from 0 to 20 wt%, the hardness of the printed WC/IN718 composite can increase from 304.8 HV to 421.3 HV. Its wear resistance was found to first increase and then decrease due to the transition of the wear mechanism. Among all the printed composites, 15 %WC/IN718 has the best wear resistance and smallest coefficient of friction. The ranking of the wear resistance of the printed composites was found to be 15 %WC/IN718 > 10 %WC/IN718 > 20 %WC/IN718 > IN718.