Theoretical and experimental study of precipitation and coarsening kinetics of 0′ phase in Al-Cu alloy

The microstructural evolution and precipitation kinetics of an Al-4.8 wt% Cu alloy were investigated by transmission electron microscope (TEM) and differential scanning calorimetry (DSC) under different heating rates. The DSC results of quenched Al-Cu alloy obtained at different heating rates were used to calculate kinetics parameters of 0 ' precipitation. The activation energy for the precipitate growth obtained by the Kissinger method and the analytical model were determined as 53.54 kJ/mol and 85 +/- 5 kJ/mol, respectively. For aged Al-Cu alloys, the typical microstructure of 0 ' precipitates and the phase relationship with the matrix were obtained. In addition, 0 ' phase coarsening kinetics is in coincident with the classical Liftshitz-Slyozov-Wagner (LSW) theory, and the calculated activation energy suggests that coarsening kinetics of 0 ' is controlled by diffusion of Cu in the matrix of the investigated Al-Cu alloy.