Compressive creep of SiC whisker/Ti3SiC2 composites at high temperature in air

Abstract

The compressive creep of a SiC whisker (SiCw) reinforced Ti3SiC2 MAX phase-based ceramic matrix composites (CMCs) was studied in the temperature range 1100-1300°C in air for a stress range 20-120 MPa. Ti3SiC2 containing 0, 10, and 20 vol% of SiCw was sintered by spark plasma sintering (SPS) for subsequent creep tests. The creep rate of Ti3SiC2 decreased by around two orders of magnitude with every additional 10 vol% of SiCw. The main creep mechanisms of monolithic Ti3SiC2 and the 10% CMCs appeared to be the same, whereas for the 20% material, a different mechanism is indicated by changes in stress exponents. The creep rates of 20% composites tend to converge to that of 10% at higher stress. Viscoplastic and viscoelastic creep is believed to be the deformation mechanism for the CMCs, whereas monolithic Ti3SiC2 might have undergone only dislocation-based deformation. The rate controlling creep is believed to be dislocation based for all the materials which is also supported by similar activation energies in the range 650-700 kJ/mol.