Effect of laser shock peening on the plasticity of Zr-based metallic glass under compression

The surface of Zr41.2Ti13.8Cu12.5Ni10Be22.5 BMG was modified in this study using LSP to enhance its compressive mechanical properties.The microstructures and thermal properties of the as-cast and laser-peened specimens were characterized using X-ray diffraction and differential scanning calorimetry, respectively. The results indicated that crystallization did not occur in the laser-peened area. Compared to the as-cast metallic glass, the LSP-treated specimen had a higher free volume. The LSP-treated specimen, as compared to the as-cast specimen with a slight plastic strain of 8.1 % prior to final fracture, exhibited an improved compressive plastic strain of 18.8 %. Based on results of the hardness tests, a significant change in microhardness was observed in the specimen after the LSP treatment. The improved plasticity and decreased hardness of the laser-peened specimen were due to the excess free volume in the laser treated surface zone. Scanning electron microscopy observations of the fracture surfaces revealed that the LSP-treated specimen formed multiple shear bands and highly dense vein-like patterns. This study provides a novel method for increasing the plasticity of metallic glasses to promote their industrial application.