An analysis of the partial structure functions in unmixed Cu-Ni-Fe alloys studied by anomalous small-angle X-ray scattering

Abstract

The solute partitioning and the unmixing kinetics of a Cu_0.43Ni_0.42Fe_0.15 alloy have been studied by anomalous small-angle X-ray scattering (ASAXS). From ASAXS data, partial structure factors (PSF) have been extracted: the homoatomic PSF curves cannot account for a pseudobinary system and one has to consider a Ni (or Fe) segregation at the interfaces between the Cu-rich phase and the Ni-Fe phase. The main contribution to the PSF comes nevertheless from the two-phase term which behaves as in the late stage of deep quenches of concentrated binary systems: PSF present a hump which increases and shifts toward low q values as power laws of the aging time: q_m^{varies as} t^-0.25, S_m^{varies as} t^0.7.