Deformation behavior of Mg-8.5wt.%Al alloy under reverse loading investigated by in-situ neutron diffraction and elastic viscoplastic self-consistent modeling

TL;DR

This study investigates the cyclic deformation behavior of Mg-8.5wt.%Al alloy with different textures using in-situ neutron diffraction and EVPSC modeling, revealing how twinning and de-twinning influence its mechanical response under reverse loading.

Contribution

It introduces a combined experimental and modeling approach to analyze the effects of initial texture and deformation mechanisms on magnesium alloy cyclic behavior.

Findings

Twinning occurs during initial compression in conventional texture alloy.

De-twinning dominates during reverse tension in conventional texture alloy.

Modified texture alloy exhibits twinning during initial tension and de-twinning during reverse compression.

Abstract

The cyclic deformation behavior of extruded Mg-8.5wt.%Al alloy with a conventional extrusion texture and a modified texture is systematically investigated by in-situ neutron diffraction and elastic viscoplastic self-consistent (EVPSC) modeling incorporating a twinning/de-twinning (TDT) scheme. The role of twinning and de-twinning on the deformation behavior of Mg-8.5wt.% Al alloy is investigated in terms of the macroscopic stress-strain response, the evolution of the activities of various deformation mechanisms, the texture evolution, the evolution of the internal elastic strains, and the evolution of the diffraction peak intensities. The alloy with the conventional extrusion texture undergoes twinning during initial compression and de-twinning during reverse tension. The same alloy does not favor twinning during initial tension, but rather during reverse compression. The alloy with a modified texture undergoes twinning during initial tension followed by detwinning during reverse compression. The results provide insights into the effect of initial texture, loading path, slip, twinning, de-twinning on the cyclic behavior of magnesium.