We have calculated binding surfaces for cia changes (along the Bain pa
th) and changes of the atomic volume of metallic systems undergoing ma
rtensitic transformations. We find characteristic differences between
the surfaces of nonmagnetic systems (with a close packed low temperatu
re structure) and magnetic systems (with a less close packed low tempe
rature structure). The ab initio calculations have been performed by u
sing the augmented-spherical-wave method within the local-density appr
oximation in the case of stoichiometrically ordered compounds and the
Korringa-Kohn-Rostocker method together with the coherent-potential ap
proximation in the case of disordered alloys.