Structural transition of Ti3SiC2 under high hydrostatic pressure: A first-principles study

We theoretically studied the phase transformation, electronic and elastic properties of Ti3SiC2 ceramic by using the pseudopotential plane-wave method within the density functional theory. Our results demonstrate that there exists a structural phase transition from α‐Ti3SiC2α‐Ti3SiC2 to β‐Ti3SiC2β‐Ti3SiC2 under pressure up to 384 GPa, and α‐Ti3SiC2α‐Ti3SiC2 is the most stable phase at zero pressure. The calculated electronic band structure and density of states reveal the metallic behavior for the polymorphs of Ti3SiC2. The mechanical stability of α‐Ti3SiC2α‐Ti3SiC2 at zero pressure is confirmed by the elastic constants, and is analyzed in terms of electronic level. By analyzing the ratio between bulk and shear moduli, we conclude that α‐Ti3SiC2α‐Ti3SiC2 is brittle in nature.

► There exists a structural phase transition from α−Ti3SiC2α−Ti3SiC2 to β−Ti3SiC2β−Ti3SiC2 under pressure up to 384 GPa, which is the first time to report this phase transition.
► α−Ti3SiC2α−Ti3SiC2 is the most stable phase at zero pressure, which is confirmed by the elastic constants and analyzed in terms of electronic level.
► α−Ti3SiC2α−Ti3SiC2 is brittle in nature by analyzing the ratio between bulk and shear moduli.