Microstructural changes and formability of Al–Mg ultrafine-grained aluminum plates processed by multi-turn ECAP and upsetting

Abstract The article focuses on an evaluation of the microstructure, mechanical properties, anisotropy and formability of ultrafine-grained plates of commercial aluminium alloy 5754, with a main addition of Mg. For manufacturing plates, a hybrid Severe Plastic Deformation process is proposed that combines multi-turn Equal Channel Angular Pressing with upsetting, a conventional metal forming process. It was possible to acquire plates of an average grain size of around 0.4 μm and a fraction of high-angle grain boundaries reaching an average of 70%. Due to the high accumulated strain during the processing, it was possible to achieve a Yield Strength and Ultimate Tensile Strength equal to 430 and 450 MPa, respectively, which is a 200 and 120% increase over the initial condition. The anisotropy of the mechanical properties in plate's plane was negligible. The Lankford parameter was used to evaluate formability, and its values proved to be similar to those acquired from other processing techniques. This combination of a substantial enhancement of mechanical properties and typical anisotropy parameters values offers an attractive technology for the production of high-strength plates suitable for further metal forming.