EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

The strain induced decomposition of the supersaturated solid solutions of Al30Zn2Cu and Al10Zn2Cu (wt.%) alloys was investigated thanks to X-ray diffraction and transmission electron microscopy. Solutionized materials were deformed at room temperature by high pressure torsion and the large plastic strain led to a concomitant grain refinement and decomposition of the supersaturated solid solution. Surprisingly however, phases that were identified in both alloys were significantly different from those predicted by thermodynamic calculations (Thermocalc®). Deformed materials were annealed at 200°C during 24h to achieve equilibrium conditions. Some of the strain induced phases clearly disappeared during this annealing indicating that they could be achieved only under the specific conditions of HPT. Based on these experimental data, the specific mechanisms leading to metastable phases formation during severe plastic deformation will be discussed.