Solid solution decomposition and Guinier-Preston zone formation in Al-Cu alloys: A kinetic theory with anisotropic interactions

摘要

Using methods of statistical kinetic theory parametrized withfirst-principles interatomic interactions that include chemical and straincontributions, we investigated the kinetics of decomposition and microstructureformation in Al-Cu alloys as a function of temperature and alloy concentration.We show that the decomposition of the solid solution forming platelets ofcopper, known as Guinier-Preston (GP) zones, includes several stages and thatthe transition from GP1 to GP2 zones is determined mainly by kinetic factors.With increasing temperature, the model predicts a gradual transition fromplatelet-like precipitates to equiaxial ones and at intermediate temperaturesboth precipitate morphologies may coexist.