2010 Volume 51 Issue 11 Pages 2025-2032
The mechanical behavior of extruded pure magnesium during low-cycle fatigue at room temperature was investigated using ultrasonic reflection methods with longitudinal and shear waves. The sound velocities and calculated mechanical properties, Young’s and shear moduli, decreased by a large percentage with an increased number of cycles. However, Poisson’s ratio and bulk modulus increased before a macroscopic crack occurred. The fatigue behavior was compared with the high-cycle one from a previous study. The fatigue stress amplitude was normalized using 0.2% proof strength to provide a reasonable figure for the mechanical property degradation that would accompany the development of void defect mainly caused by cleavage crack. The damage phase data were determined using optical microscopy, scanning electron microscopy, and Vickers hardness tests.