Effect of anisotropy on the low-cycle fatigue behavior of rolled AZ31 magnesium alloy

Low-cycle fatigue (LCF) tests were carried out to investigate the effect of anisotropy on the fatigue resistance of rolled AZ31 magnesium (Mg) alloy. The alloy showed a strong basal texture indicating that most of the basal planes of hexagonal close-packed lattice were located parallel to the rolling direction. Specimens loaded parallel to the rolling direction (RD) were easy to yield in compression, while those loaded normal to the rolled plane (ND) were easily yielded in tension by twinning. This anisotropy caused superior fatigue resistance of ND specimen by introducing the beneficial compressive mean stress. An energy-based model considering the effect of the mean stress was used for the prediction of fatigue life and the predicted results showed a good agreement with experimental data. (C) 2009 Elsevier B.V. All rights reserved.