Processing maps and microstructural events in hot deformation of an Al-Cu alloy

Abstract

This study investigates the hot deformation behavior and microstructural evolution of an AA2017 aluminum alloy with the aim of establishing optimal processing parameters through a comprehensive approach combining hot compression tests, Electron Backscatter Diffraction (EBSD) analysis, and the development of a corresponding processing map. To this end, hot compression tests were first performed on solid-solution-treated samples within a temperature range of 300 °C to 450 °C and strain rates of 0.001 s-1 to 0.1 s-1. An artificial neural network (ANN) model was developed to accurately predict the flow stress, and the corresponding processing maps were subsequently generated. Furthermore, the dominant dynamic restoration mechanisms were studied through EBSD observations and correlated with the flow behavior and the developed processing map. At low temperatures and high strain rates (e.g. 300 °C - 0.001 s-1 and 400 °C - 0.1 s-1) dynamic recovery (DRV) was found to be the governing softening mechanism, leading to highly deformed microstructures with extensive low-angle grain boundaries and inhomogeneous deformation, which corresponded to unstable regions in the processing maps. Conversely, at high temperatures and low strain rates, dynamic recrystallization (DRX) became the dominant softening process. At the highest temperature and the lowest strain rate, i.e. 450 °C - 0.001 s-1, discontinuous DRX was detected, resulting in highly refined, equiaxed, and largely strain-free microstructure, which coincided with stable regions (high efficiency areas) of the processing maps.

9 - Indústria, Innovació i Infraestructura

13 - Acció per al Clima

12 - Producció i Consum Responsables

Postprint (published version)