Pressure-dependent stability of cubic and wurtzite phases within the TiN–AlN and CrN–AlN systems

Ab initio calculations are employed to demonstrate a strong pressure dependence of the maximum AlN mole fraction preserving the cubic phase in Ti1−xAlxN and Cr1−xAlxN hard coatings before transforming to the wurtzite structure. Under a compression of 4 GPa an increase by ∼0.1 AlN mole fraction is obtained for both systems. Consequently, stress-related effects cannot be neglected in the discussion of the wide spread of experimentally obtained stability ranges.