Abstract
This paper deals with the influence of deformation twin on fatigue crack propagation in extruded AZ31 magnesium alloy (average grain size: approximately 120μm). In order to introduce the deformation twins, the specimens were compressed along the extrusion direction at several strain levels: 1%, 3% and 5%, respectively. Compact tension (CT) specimens were machined from the pre-compressed materials. Fatigue crack propagation tests were performed on an Electro-hydraulic testing machine at a stress ratio R=0.1 and a frequency of 10 Hz at room temperature in air. The fracture surfaces and the crack paths of the fatigue fractured specimens were observed by SEM and SEM-EBSD. The fatigue crack propagation rates of the specimens introduced the deformation twins are comparable to that of the as-received specimen. It appears that the fatigue crack growth is not controlled by the deformation twins at the crack tip.
