Reordering kinetics of disordered A15 compounds

The study of reordering in A15 compounds gives valuable information about atomic processes in this structure. This information is relevant to diffusion and solid-state compound growth, as well as to recovery from radiation damage. It also offers further valuable insight into the nature of radiation damage in these materials, complementing the results obtained by X-ray studies, electron microscopy, and the measurement of superconducting and normal-state properties. The extreme sensitivity of superconducting critical temperature T_c to the degree of order in the A15 compounds allows the former property to be used to monitor the reordering- process. The recovery of T_c in A15 compounds disordered thermally and by neutron irradiation has been achieved by annealing, and the data analyzed in terms of a theory of reordering due to Welch. From this analysis, it is possible to make estimates of the activation energies for atomic migration and vacancy formation in A15 compounds.