Nanoscale amorphous “band-like” structure induced by friction stir processing in Zr55Cu30Al10Ni5 bulk metallic glass

Abstract Friction stir processing (FSP) is successfully applied in Zr-based bulk metallic glass in this study. In the FSP specimen obtained, large defects and cracks are not present in the FSP region. The microstructure in the friction zone (FZ) exhibited an amorphous “band-like” structure with widths of 10–45 nm and a small number of nanoscale crystalline particles were observed along the “band-like” structure. We concluded that the nanoscale amorphous “band-like” structure obtained in this study is nanoscale shear bands. From this result, FSP is expected to be a useful method of processing bulk metallic glass with nanoscale shear bands to investigate the influence of shear bands on the deformation behavior of bulk metallic glass.