Visualization of indentation induced sub-surface shear bands of Zr-based metallic glass by nanosecond pulse laser irradiation

Characterizing the shear band of metallic glasses (MGs) is meaningful to understand its plastic deformation mechanism. However, the direct method for detecting the internal shear bands of deformed MGs with large field of view is still lacking. Inspired by the fact that surface defects have the enhanced absorption of laser energy, this study attempted to visualize the indentation induced sub-surface shear bands of Zr-based MG by nanosecond pulse laser irradiation in argon. The principle was first verified by laser irradiation of the surface scratch, and then implemented on the visualization of sub-surface shear bands. The experimental results demonstrated that the indentation induced sub-surface shear bands were successfully visualized by nanosecond pulse laser irradiation, and meanwhile, the laser irradiated surface maintained the amorphous characteristic. This study may open a new window for exploring the shear band characteristics of MGs upon external loads.