Unusual room-temperature compressive plasticity in nanocrystal-toughened bulk copper-zirconium glass

Abstract

Cast Cu₅₀Zr₅₀ alloy rods with a diameter of 1 mm have been found to consist of a glassy phase containing fine crystalline particles with a size of about 5 nm. They have a glass transition temperature T _g of 675 K, and a large supercooled-liquid region extending 57 K above T _g. The rods exhibit a high yield strength of 1860 MPa and a Young's modulus of 104 GPa. Because they contain a dispersion of embedded nanocrystals, the as-cast bulk metallic glass rods can sustain a compressive plastic strain at room temperature of more than 50%, an exceptional value which is explicable by compensation of any shear softening by nanocrystal coalescence and pinning of shear bands.

Acknowledgments

At the time of this work ARY and ALG were at the Institute for Materials Research (IMR), Tohoku University, ARY supported by the IMR International Frontier Centre for Advanced Materials (IFCAM) and ALG by a Japan Society for the Promotion of Science (JSPS) Fellowship.