NIRT: Deformation Mechanisms and Manufacturing of Nanostructured Materials Processed by Severe Plastic Deformation (SPD)

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This proposal aims to gain fundamental understanding of thedeformation mechanisms that operate in nanostructured metals andalloys, in particular in those produced by severe plastic deformation(SPD) methods. Based on this knowledge it further aims to develop fullcapability to manufacture these materials in high quality bulk forms.The extremely attractive (and rare) combination of mechanicalproperties (high strength, ductility, fatigue resistance) andmanufacturability of these materials leads to a new class of highperformance alloys for structural uses. It is understood that thiscombination of properties is due to the formation of nano-scale grainsizes in these materials, but the mechanisms responsible for the highstrength combined with high ductility are not well understood. Thispresents a fundamental obstacle to the optimization of thesematerials, or to predictions of the performance of these materials inapplications.An integrated approach with strong emphasis on manufacturing isproposed. On the theoretical side, deformation mechanisms will besimulated with crystal-plasticity aggregate models and with detailedmodels of the grains and grain boundaries. The experimental programcovers a wide a range of strain rates and temperatures, texturedevelopment, and in situ transmission electron microscopy and atomicforce microscopy to directly verify deformation mechanisms. Theexperimental results will provide validation to the theoreticalmodeling and manufacturing process simulations.Finally, simulations of the manufacturing processes will enableprocess parameter optimization. A complete, miniature, yet fullyscalable, manufacturing facility will be designed and implemented.The significant impacts of the proposed research are made possible bythe acquired fundamental understanding of the deformation mechanisms,and include advances in manufacturing techniques to produce thesehighly desirable materials in bulk. The miniature manufacturingfacility will become a source of significant quantities ofnano-structured alloys. Finally, the proposal will provide students atthe UCSD and at local K-12 schools with interdisciplinary education ina cutting-edge area of research.