Bonding properties and bulk modulus of M4AlC3 (M = V, Nb, and Ta) studied by first-principles calculations

We have investigated the bonding properties and bulk modulus of M4AlC3 (M = V, Nb, and Ta) by first-principles calculations. The calculated cohesive energy indicates the enhancement of bond strength of M4AlC3 as V is replaced by Nb and subsequently by Ta. This conclusion was further confinned by the analysis of density of states of M4AlC3. The bulk modulus of M4AlC3 is found to be proportional to its corresponding binary compound MC. The hardness of M4AlC3 was discussed based on the relationship between the bulk modulus and hardness. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim