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

The solute partitioning and the unmixing kinetics of a Cu0.43Ni0.42Fe0.15 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: qmvaries as t-0.25, Smvaries as t0.7.