Selective laser melting of in situ TiN-Ti5Si3 composites with RE-Si-Fe addition: Comparative study

A comparative study was conducted to investigate the influence of rare earth (RE)-Si-Fe addition on the microstructures and tribological properties of in situ TiN-Ti5Si3 composites prepared by selective laser melting (SLM). With the addition of 3 wt-% RE-Si-Fe, the shape of in situ TiN reinforcing particles became rounded and smoothened, the particle size was refined and the dispersion state was homogenised. Relative to TiN-Ti 5Si3 composites without RE addition, the average friction coefficient of SLM processed RE containing composites decreased from 0.85 to 0.55, and the resultant wear rate decreased from 3.79×10-4 to 2.65×10-4 mm3 N-1m-1. Metallurgical functions of the RE elements in improving the SLM processability and the resultant wear performance of in situ composites were elucidated.