First-principles growth kinetics and morphological evolution of Cu nanoscale particles in Al

The morphological evolution of nanoscale precipitates in Al-Cu alloys is studied by integrating first-principles calculations, the mixed-space cluster expansion, and Monte Carlo simulations. Without a priori assumptions, we predict generic precipitate morphologies dominated by strain-induced long-range interactions: single atomic layers consisting of 100%Cu atoms along {1 0 0} planes of a face-centered-cubic lattice of Al atoms, consistent with experimental measurements. We analyze the precipitation kinetics using the Johnson-Mehl-Avrami phase transformation theory and obtain a transformation exponent close to 1.5.