Stress equivalence during early-stage decomposition of Al 1.7 at.% Cu

To supplement X-ray and electron metallography studies during early-stage decomposition, precision activation volumes were determined by strain-rate change technique and stress equivalence between the decrease in the activation volume and the increase in yield stress was found. This result suggests that near-neighbour solute rearrangement in supersaturated random solution initially takes place with multiple-solute obstacles of greater strength to replace single-solute obstacles of higher density prior to the formation of transition phases.