Ideal shear strength and deformation behaviours of L1$_0$ TiAl from first-principles calculations

[摘要] The stressâ€�?�strain relationships for four different shear processes of L1$_0$ TiAl have been investigated from first-principles calculations, and the peak shear stresses in these slip systems were obtained. By analysing the structural unit cell, bond length and charge density, the deformation modes under shear were elaborately discussed. Both of the peak shear stresses and the charge density indicate that the ideal shear strength of L10 TiAl occurs in the $langle direction. It is shown that some bonds are enormously stretched accompanying with depletion of charge density as the strain increase. The density of states was studied in detail. It is indicated that strong hybridizationexists between Ti 3$d$ and Al 2$p$, and the structural stability would be lowered with increase of the strain.

[学科分类] 材料工程

[关键词] First-principles calculations;ideal shear strength;deformation mode;charge density;density of states.