Young's modulus at 21°C in quenched &agr; Cu‐Al alloys increases with time. This correlates with a decrease in resistivity which has been attributed to vacancy‐enhanced diffusion and short‐range ordering [M. S. Wechsler and R. H. Kernohan, Acta Met.7, 599 (1959); R. H. Kernohan and M. S. Wechsler, J. Phys. Chem. Solids18, 175 (1961)]. The total change in modulus during aging increases with Al content and quenching speed and is also a function of the quenching temperature. An effective activation energy of 0.69 ev was determined 38 min after quenching. This is an effective energy of motion for the point defects involved in the diffusion process at this point in the reaction.