Improved mechanical properties and toughening mechanism of mullite ceramics reinforced by introducing Ti 3 AlC 2 particles

Abstract Ti 3 AlC 2 , as a toughening phase, was introduced into mullite ceramics for the first time by the pressureless sintering process aiming at improving the mechanical properties. Significant enhancement in density and mechanical performance of mullite ceramics was achieved through the introduction of Ti 3 AlC 2 particles. The density of as‐prepared mullite–Ti 3 AlC 2 composites was increased by 23% (from 2.86 g/cm 3 to 3.51 g/cm 3 ) with Ti 3 AlC 2 increasing from 0 wt% to 20 wt%. The formation of the liquid phase and decomposed particles from Ti 3 AlC 2 are supposed to be responsible for the densification of mullite–Ti 3 AlC 2 composites. The optimal mechanical properties were obtained in the mullite–Ti 3 AlC 2 composites with 15 wt% Ti 3 AlC 2 . The bending strength, fracture toughness as well as Vickers hardness were reached 214.36 MPa, 4.84 MPa·m 1/2 , and 9.21 GPa, which are 40%, 74%, and 113% higher than pure mullite ceramics, respectively. The improved mechanical performance was mainly attributed to the synergetic action of crack deflection, crack branching and bridging, and strengthened grain boundary.