A UNIQUE FRAMEWORK TO DESCRIBE SHORT-RANGE ORDER AND PROPERTIES OF THE ORDERED STATE IN ALLOYS

Elastic diffuse scattering of neutrons was performed in situ on two di fferent alloys, Ni3V and Pt3V. Effective pair interactions of an Ising model were deduced from the measured short-range order parameters in the disordered phase. For this two examples, we obtain potentials that don't depend on temperature. Thus we can predict properties of the or dered state. In Ni3V, we describe correctly the temperature variation of the dissociation width of superdislocations and we compare the stab ility of different phases, L1(2) and DO22. In the case of Pt3V, we wil l show how we can relate the measured interactions with the existence of long period structures in the ordered state.