Characterisation of energy-dissipating mechanisms by Acoustic Emission technique during mechanical loading of Ti2AlC and Ti3AlC2 MAX phases: Influence of phase composition and porosity

Abstract

Mechanical properties of two ternary carbides MAX phases (Ti2AlC and Ti3AlC2) were investigated under cyclic bending tests with coupled acoustic emission monitoring (AE). Results show significant differences in terms of observed microstructural changes associated to acoustic emission response. Influence of the proportion of MAX phases and the presence of porosity in the sample were studied. It was found that homogeneous proportions of MAX phases led to an increase of interfaces in the material and thus to lower mechanical properties, with a more acoustically active behaviour. Porosity was found to be a preferential site of initiation and propagation of cracks, leading to samples enduring slower but earlier rupture.

Keywords

• MAX phases
• Mechanical properties
• Damage and failure mechanisms
• Acoustic emission technique