Selective laser melting of in situ TiN–Ti 5 Si 3 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–Ti₅Si₃ 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.