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

摘要

The cyclic deformation behavior of extruded Mg-8.5wt.%Al alloy with aconventional extrusion texture and a modified texture is systematicallyinvestigated by in-situ neutron diffraction and elastic viscoplasticself-consistent (EVPSC) modeling incorporating a twinning/de-twinning (TDT)scheme. The role of twinning and de-twinning on the deformation behavior ofMg-8.5wt.% Al alloy is investigated in terms of the macroscopic stress-strainresponse, the evolution of the activities of various deformation mechanisms,the texture evolution, the evolution of the internal elastic strains, and theevolution of the diffraction peak intensities. The alloy with the conventionalextrusion texture undergoes twinning during initial compression and de-twinningduring reverse tension. The same alloy does not favor twinning during initialtension, but rather during reverse compression. The alloy with a modifiedtexture undergoes twinning during initial tension followed by detwinning duringreverse compression. The results provide insights into the effect of initialtexture, loading path, slip, twinning, de-twinning on the cyclic behavior ofmagnesium.