Shear band morphology and fracture behavior of cold-rolled Zr52.5Ti5Cu18Ni14.5Al10 bulk metallic glass under tensile loading

The effect of the shear bands generated by cold rolling on the tensile ductility and fracture behavior of the Zr52.5Ti5Cu18Ni14.5Al10 bulk metallic glass (BMG) is analyzed. The results reveal significant changes in the fracture behavior of the cold-rolled material with respect to the as-cast BMG. Fracture in the cold-rolled glass occurs along the pre-existing shear bands forming an angle of 45 degrees with the loading direction. In addition, the fracture morphology shows a regular vein pattern oriented along the shear direction, which indicates that a considerable shear stress is active on the fracture plane. This is in contrast to the fracture behavior of the as-cast glass, where the normal stress plays a significant role. Here, the fracture angle is 55 degrees and the fracture surface is characterized by the conventional irregular pattern of radiating ridges. Finally, work-hardening was observed in the cold-rolled BMG even in the absence of visible shear band intersection. Possible alternative mechanisms for determining this behavior are discussed. (C) 2017 Elsevier B.V. All rights reserved.