Atomic ordering in Ni 3 Mn-Ni 3 V microcrystalline alloys

Neutron diffraction analysis has been used to determine concentrational dependences of the parameters of long-and short-range atomic order and the sizes of antiphase domains in Ni3Mn-Ni3Al microcrystalline alloys produced by quenching from the melt and in the quenched bulk alloys of the system. The parameters of atomic order were shown to depend on the temperature of the order-disorder transition. The γ′-phase micro-crystals were found to be characterized by high degrees of long-range order. The effect found is explained by the high degree of solid-solution supersaturation with excess vacancies formed upon quenching from the melt and, therefore, by abruptly increasing diffusion mobility of atoms.