Phase Separation Process in FeCr Alloys Studied by Neutron Small Angle Scattering

Abstract

The very early stage as well as late stage of phase separation process in FeCr alloys (Fe-20, 30, 40, 60 at%Cr) have been studied by pulsed cold neutron small angle scattering instrument (SAN). At the early stage, scattering intensity I ( q ) obeys q -2 dependence at the high q side of the scattering function. The results are in accord with the theory of Langer et al. which takes into account nonlinear and thermal fluctuations effects. At the late stage where I ( q ) shows q -4 dependence, a dynamical scaling law holds, while it is not the case for the earlier stage. Phase diagram of FeCr system is also determined by critical scattering measurements.