High temperature damping behavior and dynamic Young's modulus of magnesium matrix composite reinforced by Ti2AlC MAX phase particles

Abstract

The evolutions with the temperature of damping capacities and dynamic Young's moduli of ternary Ti2AlC particles reinforced AZ91D composites were investigated. This work has highlighted that Ti2AlC significantly contributes to the damping capacity and to dynamic moduli of composites. With increasing temperature, especially above 200 °C, the interfacial damping capacity becomes dominant and dynamic moduli of composites decrease. These trends were revealed from the transformed tensile fracture mechanisms. At room temperature, Ti2AlC particles delaminated without any decohesion between Ti2AlC particles and the Mg matrix. However, the interfacial decohesion occurred above 200 °C. One explanation of this change of decohesion mechanism could be ascribed to the inherent structure of the Ti2AlC MAX phase and to the formation of a robust amorphous magnesium layer at the interface between Ti2AlC and magnesium matrix that was evidenced by HRTEM. This amorphous layer further gives rise a high activation energies (H) of damping peaks for composites, which was calculated to 128 kJ/mol. This value is higher than those calculated for SiC or graphite reinforced AZ91D composites, making Ti2AlC particles particularly interesting for application in reinforcing magnesium composites.