Dynamic strength and fragmentation of highly oriented Ti3SiC2 under multiaxial compression

Abstract

MAX phases are distinguished by their unique kink band formation, a distinct deformation mechanism in layered materials. This study explores the influence of global grain orientation c-axis, strain rate, and stress state on the compressive response of highly oriented Ti₃SiC₂ through experimental methods. A Kolsky (or split-Hopkinson) bar is employed to evaluate the dynamic compressive response under uniaxial and biaxial (planar confinement) conditions under 10² s⁻¹ strain rate. Macroscopic ultra-high-speed visualization during loading and microscopic post-mortem fractography reveal that confinement states significantly impact both macroscopic failure patterns and microscopic fracture mechanisms. Notably, biaxial loading with dynamic load edge-on to the grains and 80 MPa planar confinement along the layers resulted in the highest dynamic compressive strength observed (1636 ± 136 MPa), a 66 % increase compared to the unconfined uniaxial dynamic condition. The planar confinement appears to delay crack propagation and enhance inelastic deformation.