Anomalous X-ray scattering study of early-stage precipitation in AlZnAg

Initial stages of phase separation in an Al14%Zn4%Ag alloy was studied by anomalous small-angle X-ray scattering. Although the three partial structure functions could not be determined individually, it was observed that composition tie-lines rotated in the course of aging time. The rotation was interpreted in terms of a change of the Ag/Zn concentration ratio within the evolving precipitates. An early stage stability analysis was also performed based on an approximate sub-regular solution model for the coherent AlZnAg ternary miscibility gap.