Superplasticity and superplastic forming ability of a Zr-Ti-Ni-Cu-Be bulk metallic glass in the supercooled liquid region

Abstract

The superplastic deformation behavior and superplastic forming ability of the Zr41.25Ti13.75Ni10Cu12.5Be22.5 (at.%) bulk metallic glass (BMG) in the supercooled liquid region were investigated. The isothermal tensile results indicate that the BMG exhibits a Newtonian behavior at low strain rates but a non-Newtonian behavior at high-strain rates in the initial deformation stage. The maximum elongation reaches as high as 1624% at 656 K, and nanocrystallization was found to occur during the deformation process. Based on the analysis on tensile deformation, a gear-like micropart is successfully die-forged via a superplastic forging process, demonstrating that the BMG has excellent workability in the supercooled liquid region.