This research is an experimental program employing quantitative transmission electron microscopy and theoretical analyses to clarify the mechanisms of precipitate nucleation and growth in model alloy systems. The role of ternary additions in affecting growth is emphasized. Defect density, solute segregation, ledge growth, and precipitate morphology and spacing are analyzed to reveal effects of systematic changes in ternary alloying additions and aging treatments. In-situ high resolution electron microscopy is employed to show atomic growth mechanisms based on dislocation ledges and to quantify interphase boundary motion.
