Structure and bulk modulus of M2AlC (M=Ti, V, and Cr)

We have performed theoretical studies of the bulk modulus of M2AlC, where M=Ti, V, Cr by means of ab initio total energy calculations using the projector augmented wave methods. Our estimated equilibrium volume and the lattice parameters (c/a) agree well (within +/-2% and +/-0.06%, respectively) with experimental data. The bulk modulus of M2AlC increases as Ti is substituted with V and Cr by 19% and 36%, respectively. This can be understood since the substitution of Ti by V and Cr is associated with an extensive increase in the M-Al and M-C bond energy. (C) 2003 American Institute of Physics.