An experimental study of anisotropic fatigue behavior of rolled AZ31B magnesium alloy

Material orientation effects on cyclic deformation and fatigue of a rolled AZ31B magnesium (Mg) alloy were experimentally studied. Monotonic tension, monotonic compression, and fully reversed strain-controlled tension-compression experiments were conducted using testing specimens taken from a rolled plate along five different directions with respect to the rolled direction (RD): 0 degrees(RD), 22:5 degrees, 45 degrees, 67:5 degrees, and 90 degrees(ND). Fatigue lives range from few loading cycles to over 106 cycles. Significant anisotropy was observed in the monotonic and cyclic deformation behavior. Cyclic hardening was observed for all five orientations at a high strain amplitude. The strain-life curves of all the material orientations form a relatively narrow band. The strain-life curve obtained from each material orientation is characterized with two distinct kink points which are closely associated with the dominating plastic deformation mechanisms, fatigue properties, and fatigue cracking behavior. The RD specimens show the highest fatigue strength while the 45 degrees specimens display the lowest fatigue strength among the five material orientations. A discussion is made on the unique deformation behavior of the 45 degrees specimens. (C) 2019 The Authors. Published by Elsevier Ltd.