title: High strain rate deformation of layered nanocomposites.
abstract: Insight into the mechanical behaviour of nanomaterials under the extreme condition of very high deformation rates and to very large strains is needed to provide improved understanding for the development of new protective materials. Applications include protection against bullets for body armour, micrometeorites for satellites, and high-speed particle impact for jet engine turbine blades. Here we use a microscopic ballistic test to report the responses of periodic glassy-rubbery layered block-copolymer nanostructures to impact from hypervelocity micron-sized silica spheres. Entire deformation fields are experimentally visualized at an exceptionally high resolution (below 10 nm) and we discover how the microstructure dissipates the impact energy via layer kinking, layer compression, extreme chain conformational flattening, domain fragmentation and segmental mixing to form a liquid phase. Orientation-dependent experiments show that the dissipation can be enhanced by 30% by proper orientation of the layers.
authors.affiliation: Department of Materials Science and Engineering, MIT, Cambridge, Massachusetts 02139, USA.
authors.forename: Jae-Hwang
authors.initials: JH
authors.lastname: Lee
authors.forename: David
authors.initials: D
authors.lastname: Veysset
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Singer
authors.forename: Markus
authors.initials: M
authors.lastname: Retsch
authors.forename: Gagan
authors.initials: G
authors.lastname: Saini
authors.forename: Thomas
authors.initials: T
authors.lastname: Pezeril
authors.forename: Keith A
authors.initials: KA
authors.lastname: Nelson
authors.forename: Edwin L
authors.initials: EL
authors.lastname: Thomas