Characterization of shear bands/cracks induced by fatigue experiment in a Zr–Cu–Al bulk metallic glass

A Zr50Cu40Al10 bulk metallic glass was deformed by three-point bending fatigue experiments. Shear bands/cracks appeared on the tensile and compressive regions of the sample surfaces. Characterizations of these shear bands/cracks cross sections by transmission electron microscopy reveal that a composition change occurred within the shear bands/cracks. Additionally, nanocrystallites with a higher copper content formed within the cracks. The composition change of the shear bands/cracks and formation of nanocrystallites are attributed to the diffusion of oxygen and copper atoms, respectively.