This effort explores mechanisms of precipitate coarsening in metal alloys that contain low volume fractions of precipitates. The mechanisms of precipitate coarsening and associated effects of elastic strain are important areas in physical metallurgy that needs to be resolved. Four binary alloys have been selected for this study to provide a range of lattice mismatches, from a low of 0.003 in the nickel/silicon system to a high of 0.0112 in the nickel/germanium system. The effects of elastic interaction and volume fraction of precipitate on particle coarsening and equilibrium shape are examined. The kinetics of coarsening are followed using the techniques of transmission electron microscopy and magnetic analysis, which enables measurement of the solute concentration in the Ni-rich matrix during coarsening. Magnetron sputtering is explored as a means of preparing alloys of precisely controlled compositions and homogeneity. %%% This research has relevance to microstructural formation and stability in high temperature metal alloys. The emphasis is on binary nickel-base alloys, the principal base for superalloy compositions development.
