Effect of Texture and Grain Size on the Compressive Creep of Ti 3SiC 2 MAX Phase Ceramics

Abstract

The sintering and simultaneous texturing of Ti₃SiC₂ MAX phase ceramics have been reported. The degree of orientation of Ti₃SiC₂ grains were quantified with X-ray diffraction for the bulk crystallographic texture and electron back scattered diffraction for local and morphological texture. Analysis revealed that the basal plane of Ti₃SiC₂ was aligned perpendicular to the direction of applied external force during sintering. The textured MAX phase was subjected to high temperature annealing to induce grain growth which resulted in a duplex microstructure. The ceramics with fine (~1 µm) and duplex (500 µm wide elongated grains in a matrix of equiaxed 1 µm grains) microstructure were subjected to compressive creep tests at high temperature (1000-1300 °C) in different directions with respect the orientation of the crystals in the bulk Ti₃SiC₂. The creep resistance was highest for fine grained Ti₃SiC₂ with basal planes aligned perpendicular to the direction of applied stress, whereas the ceramics with duplex microstructure and basal plane aligned parallel to the direction of applied stress suffered the highest creep deformation. A probable mechanism for the creep response of the different grades of Ti₃SiC₂ has been proposed.