A Novel Micro-Scale Plastic Deformation Feature on a Bulk Metallic Glass Surface under Laser Shock Peening

Laser shocking peening is a widely applied surface treatment technique that can effectively improve the fatigue properties of metal parts. We observe many micro-scale arc plastic steps on the surface of Zr_47.9Ti_0.3Ni_3.1Cu_39.3Al_9.4 metallic glass subjected to the ultra-high pressure and strain rate induced by laser shock peening. The scanning electronic microscopy and atomic force microscopy show that the arc plastic step (APS) has an arc boundary, 50–300 nm step height, 5–50 μm radius and no preferable direction. These APSs have the ability to accommodate plastic deformation in the same way as shear band. This may indicate a new mechanism to accommodate the plastic deformation in amorphous metallic glass under high pressure, ultra-high strain rates, and short duration.