First-principles study of elastic properties of cubic Cr1-xAlxN alloys

The elastic properties of paramagnetic cubic B1 (c-) Cr1-xAlxN ternary alloys are studied using stress-strain and energy-strain methods within the framework of density functional theory. A strong compositional dependence of the elastic properties is predicted. Young's modulus, E, and shear modulus, G, exhibit the same compositional trends as experimentally measured hardness values (i.e., increasing with Al content), while bulk modulus, B, remains almost constant. The isotropic elastic response in the c-Cr1-xAlxN is predicted for concentrations around x = 0.50. Brittle behavior and directional bonding characteristics are predominant in the c-Cr1-xAlxN coatings in the whole composition range and become more pronounced with increasing Al content. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4789378]