Origin of different plastic resistance of transition metal nitrides and carbides: Stiffer yet softer

Using density functional theory and the Peierls–Nabarro model, we calculated the shear strength and generalized stacking fault energy of TiN and TiC as prototypes of transition metal nitrides and carbides. In spite of its higher elastic moduli, TiN was found to have a lower plastic resistance as compared to TiC due to the higher shear strength and stacking fault energy of TiC. A mechanism based on the development of a deformed electronic structure is proposed to explain the origin of this difference in plastic resistance.