Mechanism and Kinetics of Precipitation and Dissolution of GP Zone and Metastable Phase in Al-3wt% Cu Alloy

B. Khamela, F. Sahnouneb,c, M. Fatmi c and N. Brihi a aDepartment of Physics, Mohammed Saddik Benyahia University, Jijel 18000, Algeria bPhysics and Chemistry of Materials Lab, Department of Physics, University Mohamed Boudiaf of M'sila, 28000, M'sila, Algeria cResearch Unit on Emerging Materials (RUEM), Ferhat Abbas of Setif 01, Setif 19000, Algeria

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Thermal analysis techniques remain important tools amongst the large variety of methods used for analysis of the precipitation and dissolution of the Guinier-Preston zone and metastable phase θ' in Al-3wt% Cu. In the present study, the kinetics of precipitation and dissolution of the Guinier-Preston zone and metastable phase θ' in Al-3wt% Cu was investigated using differential scanning calorimetry carried out between room temperature and 430°C at heating rates of 20, 25, and 30°C min-1. The activation energies evaluated through isothermal differential scanning calorimetry treatment using the Johnson-Mehl-Avrami theory were 25, 100, and 80 kJ mol-1 for the Guinier-Preston zone precipitation, formation of θ'/θ and dissolution of θ', respectively. The Avrami constant n obtained by the Ligero method was about 1.5 for the formation of θ'/θ indicating that bulk nucleation is dominant in θ'/θ formation controlled by diffusion from a constant number of nuclei.

DOI: 10.12693/APhysPolA.131.133 PACS numbers: 81.30.Mh, 81.70.Pg, 81.30.Bx