In Situ X-Ray Stress Analysis for the Highly Textured Mg-Base Wrought Alloy AZ31

Abstract

The deformation behaviour of the highly textured Mg-base wrought alloy AZ31 subjected to tensile and compressive elasto-plastic loading was characterized by means of synchrotron radiation. In former publications it was shown that there exists an asymmetry in the deformation behaviour of the investigated alloy, which can be related to the deformation mechanism of the hexagonal structure due to the crystallographic texture relative to the loading direction. A local X-ray stress analysis was carried out on highly textured metal sheets for different {hkil}- planes of the hexagonal crystal structure. The load transfer was investigated within in-situ loading experiments in order to account for suitable XEC´s, thus ensuring accurate stress evaluations. An X-ray imaging method was applied in order to provide bending stress distributions with a high local resolution using synchrotron radiation (beamline G3, Hasylab (DESY)). Stress analyses were carried out on the side face of a bending bar being subjected to elasto-plastic bending up to total strains in the outer layers of approximately 2%. It is distinguished between loading stress distributions measured in in-situ loading experiments as well as residual stress distributions monitored after unloading of elasto-plastically bended bars. Furthermore the loading direction was alternated, in order to investigate the effect of the twin formation as well as the reversibility of the twinning on the results of X-ray stress analysis.