First principles study of stability, electronic structure and fracture toughness of Ti₃SiC₂/TiC interface

In order to theoretically clarify the interfacial properties of the TiC-Ti₃SiC₂ composites, the work of adhesion, electronic structure and fracture toughness of Ti₃SiC₂ (001)/TiC (111) interface were calculated by first principles method. By comparing the work of adhesion and the interfacial energy, it is determined that the Ti2(Si)-H-C interface with a smooth transition from TiC (111) to Ti₃SiC₂ (001) has the highest bonding strength and thermodynamic stability. Further analysis of the electronic structure of the Ti2(Si)-H-C interface revealed that strong Ti-C mixed covalent-ionic bonds would be formed at the interface, and the electronic structure of the Ti atoms at the interface was close to that of the Ti atoms in the TiC (111) side. The first principles computational tensile tests on the Ti2(Si)-H-C interface showed that the Ti2(Si)-H-C interface tends to break at the Ti2-Si bond near the interface on the Ti₃SiC₂ (001) side.