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High-Angle Grain Boundaries and the Evolution of Texture during Severe Plastic Deformation (SPD) Pro

Terry R McNelleyCenter for Materials Science and EngineeringDepartment of Mechanical and Astronautical EngineeringNaval Postgraduate SchoolMonterey, CaliforniaAbstractThe production of highly refined microstructures in engineering alloys by application of novel SPD technologies may lead to dramatic property improvements, but realization of this potential will require improved understanding of microstructure control and microstructure – processing – property relationships. This presentation will examine high-angle boundary formation in microstructures after conventional and SPD processing of aluminum and its alloys, and the relationship between these boundaries and components of the texture. Recent orientation imaging microscopy investigations in this laboratory have revealed distinct, meso-scale band - or block-like features in processed materials. The lattice orientations within these features alternate between prominent texture orientations in a manner reminiscent of deformation banding in fcc metals. Analytical transmission electron microscopy has shown that the interfaces between these features are dislocation boundaries that may be precursors to disordered high-angle grain boundaries. Recent results on materials processed by large-strain extrusion machining will be included.About the PresenterTerry McNelley is a native of Fort Wayne, Indiana. He received his BS in Metallurgical Engineering in 1967 from Purdue and his PhD in Materials Science and Engineering in 1973 from Stanford. For the period 1972-76 he was a faculty member in the Department of Mechanical Engineering at the University of Wyoming, and from 1976 – present he has been in the Mechanical Engineering Department at the Naval Postgraduate School, serving as Department Chair from 1996 – 2002. He has held visiting appointments at institutions in England (1980-81), Japan (1993) and Spain (1999). Professor McNelley's interests include microstructure – processing – property relationships in metallic materials; deformation processing, microstructures, recrystallization and superplasticity; and metal matrix composites. He was elected Fellow of ASMI in 2001.

Location: Seaver Science Library (SSL) Room 150

Audiences: Everyone Is Invited

Contact: April Mundy