Effect of twins and plastic-deformation anisotropy of extruded magnesium alloy on fatigue crack growth and crack closure behavior

To study the effect of twins and plastic deformation anisotropy on the fatigue crack growth (FCG) behavior and crack closure behavior of extruded AZ31B magnesium alloys, two types of single-edge notched tensile specimens were prepared, with loading directions parallel (specimen E) and perpendicular (specimen T) to the extrusion direction (ED). FCG experiments using these specimens were performed at stress ratios R = 0.1 and −1, and cyclic speed of 10 Hz.