Shear fracture behavior of Ti3SiC2 induced by compression at temperatures below 1000 °C

Polycrystalline titanium silicon carbide (Ti3SiC2) samples with grain size of 20-50 μm were synthesized from 2Ti/2Si/3TiC powder at 1300 °C for 60 min through the pulse discharge sintering (PDS) technique. Compressive tests were conducted on the Ti3SiC2 specimens at temperatures up to 930 °C in vacuum. The results showed that the Ti3SiC2 specimens displayed obvious shear fracture behavior and monotonically decreasing fracture strength from 935 MPa (25 °C) to 640 MPa (930 °C). On the macro-scale, the shear fracture surfaces make an angle of 23-31° with respect to the stress axis. In micro-scale, the main deformation and damage modes consist of sliding, buckling and fracture of grains, kinking and intergranular cracking. The macro-shear fracture mechanism of Ti3SiC2 is quite analogous to other brittle materials, such as polycrystalline ice and bulk metallic glasses (BMGs). Based on the results available, the shear fracture mechanism of Ti3SiC2 is discussed and related to the behavior of other brittle materials.