Order-disorder transformation mechanism in aluminum-doped Ni3Mn alloy

The kinetics of order-disorder transformation in Ni₃(Mn, Al) alloys prequenched from 700°C has been studied by neutron-diffraction analysis. Within the framework of the I. M. Lifshits model, it is shown that in Ni₃(Mn, Al) alloys containing 2.0 and 4.3 at.% aluminum, ordering proceeds by the homogeneous mechanism at 400° and by nucleation and growth at 450°. The causes are discussed of the sharp speedup of the order-disorder transformation in its first stage in aluminum-doped Ni₃Mn alloy as compared with the binary alloy.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 24–28, April, 1977.