Atomic ordering in Ni3Mn-Ni3Ti microcrystalline alloys

Abstract

Neutron diffraction is used to determine the concentration dependences of the long-and short-range order parameters and the antiphase-domain size in Ni3Mn-Ni3Ti microcrystalline alloys produced by melt quenching and the initial bulk alloys quenched from 1433 K. The dependences of the order parameters on the order-disorder transition temperatures are determined. Microcrystals of the γ’ phase are found to have a high long-range order parameter as compared to this parameter in the bulk alloys. This fact is explained by the high degree of supersaturation of a solid solution with excess vacancies formed during melt quenching and, hence, a sharp increase in the atomic diffusion mobility.