Investigation on the lattice vibration, mechanical properties, stress-strain behavior and electronic properties of FeTiSi, CoTiSi and NiTiSi intermetallics from a first-principles calculations

In the present work, we have investigated the structural, electronic, elastic and thermodynamic properties of titanium alloy (XTiSi) (X = Fe, Co, Ni) by using the first-principles calculations. The results showed that XTiSi are dynamically and thermodynamically stable. And the sequence of phase stability is CoTiSi > FeTiSi > NiTiSi. According to the mechanical parameters, three XTiSi ternary alloys exhibit mechanical stability based on the Born stability criteria. FeTiSi exhibits the strongest compression resistance, shear resistance and elastic hardness. The ductility of three alloys is ranked in the order NiTiSi > CoTiSi > FeTiSi. Stress-strain curves are considered by stretching along two directions [100] and [001] directions for three XTiSi alloys. The three-dimensional constructions and two-dimensional projection of elastic moduli were calculated to visually display the anisotropy of three XTiSi alloys. The Debye temperature show that the FeTiSi has good thermal conductivity and chemical bond strength. The electronic structures were used to discussed the magnetic properties, mechanical properties and bonds properties.