Tech Briefs

Capabilities for tailoring material properties for new uses are under development.

A continuing program of research is devoted to understanding composite materials that include nanostructured shape-memory alloy (SMA) constituents and to developing methods of fabricating components from such materials. This research is intended to improve the utilization of SMAs in microscopic structures and miniaturized devices.

Composite materials that include SMAs afford the opportunity to investigate a variety of host-guest interactions at both molecular and bulk levels. In this research, SMAs have been combined with various polymeric and metal host matrix materials, and a variety of techniques for preparation and characterization have been used to determine the extent to which each component of each composite influences the other. New techniques for producing SMA particles that are very small but still exhibit shape memory and pseudoelasticity have been developed. The composite materials studied in this program have shown promising fracture-toughness behavior. Such studies could, potentially, yield adaptive composite materials and components made from such materials in which the SMA constituents can be used to actively or passively control material and structural properties.

The main issues addressed in this research have been the following:

  • Mechanical rolling and folding for producing SMA nanoparticles and SMA composite materials,
  • The influence of grain refinement and cold working on the mechanical behavior of nanostructured SMAs produced by mechanical alloying, and
  • Optimization of chemical functionalization for tailoring the adhesion of SMA particles in a composite matrix.

A separate part of this research has been concerned with manipulation, by use of magnetic fields, of individual nanowires with nickel end caps. Such manipulation can be useful for positioning samples and may, potentially, be useful as a means of utilizing nanowire-based devices as optical switches.

This work was done by Wendy C. Crone, Arthur B. Ellis, and John H. Perepezko of the University of Wisconsin for the Air Force Office of Scientific Research.

AFRL-0083

This Brief includes a Technical Support Package (TSP).

Composites Containing Nanostructured Shape-Memory Alloys (reference AFRL-0083) is currently available for download from the TSP library.

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