Improved strength-impairing contact damage resistance of Ti3Si(Al)C2/SiC composites

The resistance of Ti3Si(Al)C2-based materials to strength-impairing contact damage was investigated using the Hertzian indentation method. Microstructural analysis indicated that for the three types of testing materials the contact damage was governed by multiple grain slip, crushed grains, and intergranular shear failure. No cone cracking or other macro-cracks were visible on or beneath the contact damage surfaces. Bending tests on the specimens containing single-cycle contact damage revealed that the resistance of Ti3Si(Al)C2 to strength degradation was significantly improved by incorporating SiC particles into the matrix. The mechanism of the improvement is ascribed to the increased shear resistance and the fact that the hard SiC particles inhibit the downward extent of the contact damage through restricting the slip and deformation of the Ti3Si(Al)C2 grains.