Kinetics of short-range-ordering in αCu–10at.% Al conducted through differential isothermal calorimetry as influenced by solute–vacancy complexes

A modified first-order kinetic law which takes into account defect decay during an ordering process was employed to predict the short-range-order kinetics of a quenched αCu–10at.% Al alloy, in conjunction with experiments performed by differential isothermal calorimetry (DIC). The effective activation energy of point defect migration and its temperature dependence strongly suggests the contribution of bound vacancies to the ordering process. An estimate of 87.6 kJ mol−1 was made for the activation energy of solute–vacancy migration by applying an effective rate constant, a value which is quite reasonable, since it lies between the activation energy of migration of unbound vacancies and the activation energy for complex dissolution. The isothermal curves were utilized to determine the ordering energy: w=−3.66 kJ mol−1.