Friction stir processing of nanostructured metal matrix composites
Friction stir processing has been developed as a method for modifying the microstructure and properties of an alloy. However, no efforts have been made to determine how the formation of amorphous phases can be promoted during friction stir processing, or whether a composite involving an amorphous or nanocrystalline matrix and carbon nanotubes can be synthesized. These nanostructured composites offer desirable properties in terms of strength to weight ratio, wear resistance, and impact toughness. The goal will be to establish which factors control the formation of nanostructured composites via friction stir processing, and to characterize their microstructures and properties.
The goal of the proposed work will be to synthesize nanostructured composites by friction stir processing and characterize their microstructure, mechanical performance, and thermal stability. The processing conditions and base material chemistry promoting formation of amorphous and nanostructured phases will be determined. The influence of processing parameters on material flow and the dispersion of carbon nanotubes in the metal matrix will also be examined using SEM and optical microscopy. Ultimately, these findings will help to develop an understanding of structure-property relations in nanostructured composites, as well as the influence of severe plastic deformation on amorphous metals. A major focus will be to establish the role of microstructure on the deformation mechanisms, and thermal stability of these materials.
A dedicated friction stir processing machine will be used to synthesize nanocrystalline and amorphous metals, as well as composites reinforced by carbon nanotubes. The student will be trained in the operation of the equipment, and techniques for fabricating the composites.