Microstructure and Wear Resistance of TiC/Ni₃Al Composites Made by Pressureless Melt Infiltration Processing

Porous TiC-Ni3Al performs were fabricated by using Ni, Al, Ti and graphite powder with self-propagating high-temperature combustion synthesis (SHS) method. Then, the porous perform were infiltrated with melt Ni3Al via the conventional pressureless infiltration process to prepare TiC/Ni3Al composites. Effects of the infiltration temperature and time on the microstructure, hardness and wear resistance of the composites were studied. XRD, SEM and EDS were used to analyze the phase identification and the solubility of Ni3Al and TiC in each other. The results show that pressureless melt infiltration is an effective method to fabricate dense TiC/Ni3Al composites. The infiltration time can greatly decrease when the infiltration temperature suitably increases. No obvious effect of the infiltration temperature and time on the hardness and the wear resistance of the composites were found. Ni3Al and TiC were well bonded, and they are the only two phases in the composites after infiltration. The wear resistance of TiC/Ni3Al composites including 70% and 80% TiC were promoted 3.25 and 4.33 times compared with pure Ni3Al, respectively.