Elastic constants of BCC binary alloys near the A3B composition and their relation to martensitic transitions

The present work deals with the analysis of the atomic-order dependence of the elastic constants of a BCC binary alloy near the A 3 B composition. The authors assume that each atom interacts with nearest and next-nearest neighbours through a pairwise interatomic potential. The configurational phase diagram of the system has been obtained from Monte Carlo simulation of a lattice model for such an alloy system. The DO 3 , B2 and A2 phases are found to be stable for appropriate values of the interaction parameters. The elastic constants of partially ordered configurations are calculated at T=0 K, after quenches from different temperatures T q ranging over the stability regions of the three phases. The results are compared with experimental data corresponding to the Cu-Zn-Al shape memory alloy and their relevance in connection with the martensitic transformation is discussed.