Influence of Heat Treatment on Microstructure and Wear Properties of TiC/FC250 Composites

Metal matrix composites (MMCs) produced through the unique liquid pressing infiltration (LPI) process exhibit significant industrial potential. In this study, TiC/FC250 metal matrix composites were fabricated using the liquid pressing infiltration process, and the effects of austempering and quenching–tempering heat treatments on the microstructure and wear characteristics were investigated in comparison to as-cast specimens of both the FC250 gray cast iron matrix material and the TiC/FC250 metal matrix composites without heat treatment. The results indicated that the quenching–tempering heat treatment effectively enhanced the dry sliding friction and wear characteristics compared to the as-cast condition. The heat-treated specimens, under optimal conditions, demonstrated superior properties compared to other heat treatments and the matrix material. Although the metal matrix composites were successfully produced via the liquid pressing infiltration process and optimal heat treatment, some graphite morphology transformed from a flake to a spherical shape due to the high temperature and slow cooling rate during the process. With the quenching–tempering heat treatment, the wear resistance increased by approximately 41.53% in the matrix material and by 53.38% in the metal matrix composites compared to the as-cast specimens. The TiC/FC250 metal matrix composite heat-treated under optimal conditions exhibited an approximate 58.28% reduction in the friction coefficient compared to the FC250 gray cast iron.