Low Shear Strength and Shear-Induced Failure in Ti3SiC2

Shear strength and shear-induced Hertzian contact damage in Ti_3SiC_2 were investigated using double-notched-beam specimen and steel spherical indenter, respectively. The shear strength of 40 MPa that was only about 10% of bending strength was obtained for this novel ceramic. The SEM fractograph of specimens failed in shear test indicated a combination of intergranular and transgranular fracture. Under a contact load, plastic indent without cone crack could be formed on the surface of Ti3SiC2 sample. Optical observation on side view showed half-circle cracks around the damage zone below the indent, and the crack shape was consistent with the contrail of the principal shearing stress. The low shear strength and the shearing-activated intergranular sliding were confirmed being the key factors for failure in Ti3SiC2.