title: Dynamic creation and evolution of gradient nanostructure in single-crystal metallic microcubes.
abstract: We demonstrate the dynamic creation and subsequent static evolution of extreme gradient nanograined structures in initially near-defect-free single-crystal silver microcubes. Extreme nanostructural transformations are imposed by high strain rates, strain gradients, and recrystallization in high-velocity impacts of the microcubes against an impenetrable substrate. We synthesized the silver microcubes in a bottom-up seed-growth process and use an advanced laser-induced projectile impact testing apparatus to selectively launch them at supersonic velocities (~400 meters per second). Our study provides new insights into the fundamental deformation mechanisms and the effects of crystal and sample-shape symmetries resulting from high-velocity impacts. The nanostructural transformations produced in our experiments show promising pathways to developing gradient nanograined metals for engineering applications requiring both high strength and high toughness-for example, in structural components of aircraft and spacecraft.
authors.affiliation: Department of Materials Science and NanoEngineering, Rice University, Houston, TX 77005, USA. thevamaranr@rice.edu elt@rice.edu.
authors.forename: Ramathasan
authors.initials: R
authors.lastname: Thevamaran
authors.affiliation: Department of Materials Science and NanoEngineering, Rice University, Houston, TX 77005, USA.
authors.forename: Olawale
authors.initials: O
authors.lastname: Lawal
authors.affiliation: Department of Materials Science and NanoEngineering, Rice University, Houston, TX 77005, USA.
authors.forename: Sadegh
authors.initials: S
authors.lastname: Yazdi
authors.affiliation: Department of Polymer Science and Engineering, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: Seog-Jin
authors.initials: SJ
authors.lastname: Jeon
authors.affiliation: Department of Mechanical and Industrial Engineering, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: Jae-Hwang
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Materials Science and NanoEngineering, Rice University, Houston, TX 77005, USA. thevamaranr@rice.edu elt@rice.edu.
authors.forename: Edwin L
authors.initials: EL
authors.lastname: Thomas