Effect of selective laser melting process parameters on microstructural and mechanical properties of TiC-NiCr cermet

TiC-NiCr cermet was in situ synthesized through selective laser melting (SLM) process using a Ti, C, and Ni80Cr20 powder mixture. Feedstock powder was prepared using high energy milling and mixing for a total time of 15 h. The effects of input energy density on the phase evolution and microstructure of SLM samples were investigated using X-ray diffractometery (XRD) and field emission scanning electron microscope (FESEM) equipped with an energy dispersive spectrometer (EDS). The density of in situ fabricated cermets was measured using Archimedes' principle, and microhardness and fracture toughness of the samples were determined through Vickers hardness test. Increasing the input energy density from 138.7 to 378.2 Jmm(-3) resulted in an increase in relative density from 93.07% to 97.49% of theoretical density. Moreover, the microhardness and fracture toughness of the manufactured cermets increased to 1369.5 HV1 and 25.96 MPa m(1/2), respectively. Further increasing of the energy density up to 416 J mm(-3) resulted in lower density and increased porosities. Additionally, it resulted in a slight decrease in microhardness and fracture toughness.