Dynamic strain aging behavior of an ultra-fine grained Al-Mg alloy (AA5052) processed via classical constrained groove pressing

Abstract

In this study, severe plastic deformation (SPD) was employed on an Al-Mg alloy (AA5052 series) in the annealed condition with sheet form geometry by using the classical constrained-groove pressing (CGP) process up to two passes at room temperature, and accordingly an equivalent plastic strain of ∼2.32 imposed into the sheets. In relation to the microstructural features (cellular structure formation and precipitates morphology), dynamic strain aging behavior of these processed Al-Mg alloys up to different passes were evaluated by elaborating the tensile property along rolling (RD) and transverse directions (TD) of sheets in terms of anisotropy. Also, the effects of thermo-mechanical treatment in H34-temper condition on the characteristics of Al-Mg alloy was elaborated and compared with the SPD processing, as well. The results showed refinement of coarse grain structure (∼50μm) for initial annealed alloy into the ultra-fine range (400–500nm) after implementation of two CGP passes with significant homogenous enhancement of mechanical property. Hardness, yield, and tensile strengths were continuously improved up to ∼55%, 110%, and 20%, respectively, with a considerable deterioration of elongation (>90%). Notably, the strengthening mechanisms were elaborated by dislocation-based models to establish a microstructure–mechanical strength relationship.