Room and High-Temperature Sliding Wear Behavior of In Situ TiC-Based Cermet Fabricated through Selective Laser Melting

In situ TiC-NiCr cermet was manufactured through the selective laser melting (SLM) of an elemental powder mixture prepared using high energy milling for 15 hours. Effects of the applied laser energy densities (138.7, 218.9, 346.7, 378.2 and 416 J.mm(-3)) on the microstructure, densification, hardness and wear properties of the samples were investigated. Microstructural evaluation of the SLM processed samples using scanning electron microscopy showed that energy densities of lower than 346.7 J.mm(-3) result in a relatively non-uniform distribution of TiC and more defects in the cermets. It was also found that by increasing the energy density to 416 J.mm(-3); densification is affected due to increased defects. Vickers microhardness test was used for hardness measurement, which showed the highest average hardness value of 1369.5 HV1 at a laser energy density of 378.2 J.mm(-3). However, hardness decreased at energy densities of higher than 378.2 J.mm(-3). Pin-on-disk dry sliding wear tests were conducted at room (for SLM processed samples) and elevated temperatures (for the specimen manufactured at 378.2 J.mm(-3) energy density). The results showed that increasing the input energy density causes a slight improvement in wear resistance at room temperature. At elevated temperatures, the wear rate showed fluctuations, and the lowest wear rate and friction coefficient were achieved at 600 degrees C.

Automated summary

In this study, in situ TiC-NiCr cermet was fabricated using selective laser melting with different energy densities. Microstructural evaluation showed that lower energy densities led to non-uniform distribution of TiC and increased defects, while higher energy densities affected densification. The highest hardness was achieved at 378.2 J.mm(-3) energy density, but it decreased at higher values. Wear resistance improved slightly with increased energy density at room temperature, and the lowest wear rate was observed at 600 degrees C during elevated temperature testing.