title: Highly monodisperse core-shell particles created by solid-state reactions.
abstract: The size distribution of particles, which is essential for many properties of nanomaterials, is equally important for the mechanical behaviour of the class of alloys whose strength derives from a dispersion of nanoscale precipitates. However, particle size distributions formed by solid-state precipitation are generally not well controlled. Here we demonstrate, through the example of core-shell precipitates in Al-Sc-Li alloys, an approach to forming highly monodisperse particle size distributions by simple solid-state reactions. The approach involves the use of a two-step heat treatment, whereby the core formed at high temperature provides a template for growth of the shell at lower temperature. If the core is allowed to grow to a sufficient size, the shell develops in a 'size focusing' regime, where smaller particles grow faster than larger ones. These results suggest strategies for manipulating precipitate size distributions in similar systems through simple variations in thermal treatments.
authors.affiliation: National Center for Electron Microscopy, Materials Science Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA. VRRadmilovic@lbl.gov
authors.forename: V
authors.initials: V
authors.lastname: Radmilovic
authors.forename: C
authors.initials: C
authors.lastname: Ophus
authors.forename: E A
authors.initials: EA
authors.lastname: Marquis
authors.forename: M D
authors.initials: MD
authors.lastname: Rossell
authors.forename: A
authors.initials: A
authors.lastname: Tolley
authors.forename: A
authors.initials: A
authors.lastname: Gautam
authors.forename: M
authors.initials: M
authors.lastname: Asta
authors.forename: U
authors.initials: U
authors.lastname: Dahmen