Effect of laser shock peening on the compressive deformation and plastic behavior of Zr-based bulk metallic glass

The compressive deformation and the plastic behavior of Zr35Ti30Cu8.25Be26.75 bulk metallic glass (BMG) in as-cast and laser peened state were investigated. It was found that as-cast sample displayed brittle fracture with an limited plastic strain of 0.22% and the fracture was mainly localized on one single shear band. For laser peened sample, an apparent plastic strain of 1.48% could be observed in the stress-strain curve, which was much greater than that of as-cast sample. Scanning electron microscope observations revealed that the normal fracture surfaces of both samples displayed a shear mode and consisted of vein like structure. The relatively uniform distribution of multiple shear bands was observed on the side fracture surface of laser peened sample. Numerical simulation was performed to understand quantitatively the plasticity enhancement of laser peened sample. Under the effect of LSP induced residual stress, the laser peened sample exhibited a larger concentrated stress around the main shear stress plane which could promote the initiation of new shear bands. Besides, the increased free volume in main shear stress plane were beneficial for the generation of multiple shear bands which would probably improve the compressive plasticity of Zr-based BMG. (C) 2016 Elsevier Ltd. All rights reserved.