Abstract Scope |
We present a systematic study of structural, electronic and mechanical properties of cleaved and sheared MAX phase (M 2 SiC: M= Sc, Ti, V, Cr, Mn, Fe, Co, Cu, Mo, Nb, Ni, Y, Zr, Ta, Hf, Ta) using first-principles density functional theory. Our focus remains on the cleave/shear (simple alias) deformation of M-A layer as the weaker metallic bonds between M-A make the deformation easier. Interestingly, we directly connect the mechanical behavior of cleaved/sheared M 2 SiC to changing interstitial electron-counts and atomic-size while moving across the periods and groups of the periodic table, respectively. The predicted elastic constants obey the well-known Born stability criteria and indicate the mechanical stability as a function of the cleave/shear distance (0-3 Å). The Pugh’s ratio (G/K) has been used to establish ductility or brittleness. We also discuss the effect of vacancies on the structural, electronic and mechanical properties of M2SiC MAX Phases. |