Improved mechanical properties and toughening mechanism of mullite ceramics reinforced by introducing Ti3AlC2 particles

摘要

Ti3AlC2, 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 Ti3AlC2 particles. The density of as-prepared mullite-Ti3AlC2 composites was increased by 23% (from 2.86 g/cm(3) to 3.51 g/cm(3)) with Ti3AlC2 increasing from 0 wt% to 20 wt%. The formation of the liquid phase and decomposed particles from Ti3AlC2 are supposed to be responsible for the densification of mullite-Ti3AlC2 composites. The optimal mechanical properties were obtained in the mullite-Ti3AlC2 composites with 15 wt% Ti3AlC2. The bending strength, fracture toughness as well as Vickers hardness were reached 214.36 MPa, 4.84 MPa center dot 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.