The main objective of this first-year assessment is to establish a strong foundation for the study of the role of microstructural attributes (grain size, twin density, and texture) on the fatigue behavior of the rolled AZ31 magnesium alloy in different orientations. The mechanical response and the low cycle fatigue behavior under fully-reversed cyclic deformation were determined in the rolling direction (RD), normal direction (ND), and 45˚ between RD and ND in a rolled AZ31 Mg alloy for different cyclic strain amplitudes. The shape of the cyclic stress-strain curves depended on the direction due to the strong texture of the alloy and to the development of twinning/detwinning under certain combinations of load and orientation.
Cyclic hardening under compression and tension occurred due to the presence of twinning and slip. Moreover, the twin volume fraction of the broken samples depended on whether the sample was broken in tension or compression, indicating that twining-detwinning occurs during the whole fatigue life.