Thermal and mechanical analyses of an EN AW 6082 alloy with static and dynamic precipitations

Abstract

Abstract In this study, the microstructural characterization of a solution annealed and quenched EN AW 6082 alloy was performed that was subjected to cold deformation (10 and 30%) and equal channel angular pressing. The findings showed that a band structure was formed, the crystallite size decreased significantly as well as that the dislocation density and stored energy increased due to severe plastic deformation. Static and dynamic precipitations in the processed alloys were characterized by thermal analyses and it was observed that precipitation sequence in heating shifted to lower temperatures due to increased kinetics caused by deformation. Increased precipitation kinetics due to severe plastic deformation could be seen in the variation of hardness during aging at 190 °C and the peak hardness of deformed alloys shifted to shorter aging times. The peak hardness of conventional heat-treated alloy was attained as 122 HV0.5 for 300 min, whereas the same hardness was achieved for an aging time of 45 min in the 30% cold-deformed alloy. By severe plastic deformation, the highest peak hardness was obtained as 130 HV0.5 after aging for 15 min. Microstructural characterization on overaged alloys indicated that the alloy having the highest stored energy had the highest tendency for recrystallization.