Shear bands distribution on the surface of deformed Zr-based BMG samples

Abstract

Initial BMG Zr62Cu22Al10Fe5Dy1 samples and the samples after high-pressure torsion (HPT) weresubjected to a flexural test. Further, the surface on a tensile side of each sample closest to the fractureedge was observed using scanning electron microscopy (SEM) consistently for the initial state andthe states after 1, 5 and 10 HPT revolutions. HPT processing was carried under a pressure P = 6 GPaon ⌀10 mm anvils with a 0.3 mm depth groove, with a rotation speed of 1 rpm, at room temperature(RT). As blanks for mechanical testing, rectangles with parameters of 10 mm in length, 2 mmin width and 0.6 mm in height were cut from alloy disks. During the present study, we found a tendencyto decrease in the shear bands density from the edge of the fracture to the far end band, accompaniedby an increase in the average distance be-tween adjacent bands with distance from the edge of thefracture. The sample subjected to 10 HPT revolutions showed greater plasticity, i.e. it experiencedgreater plastic deformation before fracture, compared to initial one. Furthermore, there was no increasein the density of bands on the sample surface after HPT and three-point bending. Probably,during HPT there are additional deformation mechanisms, replacing the formation of pronouncedbands on the surface.