Effects of Basal-texture Inclination on Bending Formability in Mg-Al-Zn-Ca Alloys

Abstract

Flame-resistant magnesium alloy containing Ca is attracting attention in the transportation field because it is safe and lightweight. In this study, the effects of texture on bending formability were investigated for samples having different forms of texture that were cut from an extruded Mg-Al-Zn-Ca alloy plate at different angles ranging from 0° to 90° from the extrusion direction. Tensile and compressive deformation behaviors were also examined to discuss the shift of a neutral layer in bending. For bending, it was shown to be preferable that the basal texture not be inclined in low-strain region because of tension/compression asymmetry. However, in high-strain region, the influence of the shift of the neutral layer was weakened. In the experiment, the sample with a cutting angle of 45° exhibited the best bending formability. Furthermore, the result of a verification test using a sheet fabricated by a lateral extrusion, named friction-assisted extrusion (FAE), in which the basal texture was controlled to be inclined, showed that FAE improves the bending formability. This was confirmed by microstructural observation of the cross section near the tension surface at the same bending radius. The number of deformation twins that cause voids and cracks was reduced by controlling the basal texture to be inclined.