title: Effects of helium implantation on the tensile properties and microstructure of Ni73P27 metallic glass nanostructures.
abstract: We report fabrication and nanomechanical tension experiments on as-fabricated and helium-implanted ∼130 nm diameter Ni73P27 metallic glass nanocylinders. The nanocylinders were fabricated by a templated electroplating process and implanted with He(+) at energies of 50, 100, 150, and 200 keV to create a uniform helium concentration of ∼3 atom % throughout the nanocylinders. Transmission electron microscopy imaging and through-focus analysis reveal that the specimens contained ∼2 nm helium bubbles distributed uniformly throughout the nanocylinder volume. In situ tensile experiments indicate that helium-implanted specimens exhibit enhanced ductility as evidenced by a 2-fold increase in plastic strain over as-fabricated specimens with no sacrifice in yield and ultimate tensile strengths. This improvement in mechanical properties suggests that metallic glasses may actually exhibit a favorable response to high levels of helium implantation.
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States.
authors.forename: Rachel
authors.initials: R
authors.lastname: Liontas
authors.forename: X Wendy
authors.initials: XW
authors.lastname: Gu
authors.forename: Engang
authors.initials: E
authors.lastname: Fu
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Wang
authors.forename: Nan
authors.initials: N
authors.lastname: Li
authors.forename: Nathan
authors.initials: N
authors.lastname: Mara
authors.forename: Julia R
authors.initials: JR
authors.lastname: Greer
keywords: Amorphous; Ni−P; ductility; irradiation; mechanical properties