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

University Of California-San Diego, La Jolla CA

Investigators

Abstract

This proposal aims to gain fundamental understanding of the deformation mechanisms that operate in nanostructured metals and alloys, in particular in those produced by severe plastic deformation (SPD) methods. Based on this knowledge it further aims to develop full capability to manufacture these materials in high quality bulk forms. The extremely attractive (and rare) combination of mechanical properties (high strength, ductility, fatigue resistance) and manufacturability of these materials leads to a new class of high performance alloys for structural uses. It is understood that this combination of properties is due to the formation of nano-scale grain sizes in these materials, but the mechanisms responsible for the high strength combined with high ductility are not well understood. This presents a fundamental obstacle to the optimization of these materials, or to predictions of the performance of these materials in applications. An integrated approach with strong emphasis on manufacturing is proposed. On the theoretical side, deformation mechanisms will be simulated with crystal-plasticity aggregate models and with detailed models of the grains and grain boundaries. The experimental program covers a wide a range of strain rates and temperatures, texture development, and in situ transmission electron microscopy and atomic force microscopy to directly verify deformation mechanisms. The experimental results will provide validation to the theoretical modeling and manufacturing process simulations. Finally, simulations of the manufacturing processes will enable process parameter optimization. A complete, miniature, yet fully scalable, manufacturing facility will be designed and implemented. The significant impacts of the proposed research are made possible by the acquired fundamental understanding of the deformation mechanisms, and include advances in manufacturing techniques to produce these highly desirable materials in bulk. The miniature manufacturing facility will become a source of significant quantities of nano-structured alloys. Finally, the proposal will provide students at the UCSD and at local K-12 schools with interdisciplinary education in a cutting-edge area of research.