title: Design of stable nanocrystalline alloys.
abstract: Nanostructured metals are generally unstable; their grains grow rapidly even at low temperatures, rendering them difficult to process and often unsuitable for usage. Alloying has been found to improve stability, but only in a few empirically discovered systems. We have developed a theoretical framework with which stable nanostructured alloys can be designed. A nanostructure stability map based on a thermodynamic model is applied to design stable nanostructured tungsten alloys. We identify a candidate alloy, W-Ti, and demonstrate substantially enhanced stability for the high-temperature, long-duration conditions amenable to powder-route production of bulk nanostructured tungsten. This nanostructured alloy adopts a heterogeneous chemical distribution that is anticipated by the present theoretical framework but unexpected on the basis of conventional bulk thermodynamics.
authors.affiliation: Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Tongjai
authors.initials: T
authors.lastname: Chookajorn
authors.forename: Heather A
authors.initials: HA
authors.lastname: Murdoch
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Schuh