Shear strength and shear failure of layered machinable Ti3AlC2 ceramics

Shear-induced failures in uniaxial compression and Hertzian contact damage of Ti3AlC2 fabricated by a solid-liquid reaction synthesis were investigated, and shear strength was evaluated using double notched samples and punch hole tests respectively. Compressive strength of 749 MPa and the slip angle of 38degrees between the slip plane and the loading direction were measured when the applied load was parallel to the hot-pressing direction of the material; whereas the compressive strength of 841 MPa and the angle of 26degrees were obtained when the applied load was perpendicular to the hot-pressing direction. The shear strength obtained using double-notched sample was 96 MPa and that from punch-shear test was 138 MPa, respectively. SEM fractographs of specimens failed in shear and compression tests indicated a combination of intergranular and transgranular fracture and also an evidence of friction in the slip plane during compression failure process. Punch-shear test was developed and confirmed to be a simple and feasible method for determining the shear strength of layered machinable ceramics. (C) 2003 Elsevier Ltd. All rights reserved.