MATERIALS SCIENCE AND ENGINEERING SEMINAR Characterization of Surface Microstructure in Pure Copper After Severe Plastic Deformation by Sliding by Sergey Suslov Ph.D. Final Examination Co-Advisors: Prof. K. Trumble and Prof. S. Chandrasekar ABSTRACT This study concentrates on the characterization of the surface and sub-surface microstructure and texture evolution in pure copper after severe plastic deformation (SPD) in the form of "wave" sliding. This deformation process, based on conventional machining with modifications in the deformation geometry, is used to address the effects of strain and strain rate on the microstructural parameters like the spacing of geometrically necessary boundaries (GNBs) and incidental dislocation boundaries (IDB), fraction of high-angle boundaries and the development of deformation texture. Transmission Electron Microscopy (TEM), Electron Backscatter Diffraction (EBSD) and Vickers microhardness testing were utilized in this work. It was observed that "wave" sliding using -70* and -80* rake angle resulted in the formation of a sub-surface homogeneous strain distribution layer. It was revealed that the material strain-hardened to a larger depth with one pass at a more positive rake angle, and with each consecutive pass (1-8) at -70* rake angle. It was also shown that simple shear was the main deformation mode in "wave" sliding, and the deformation textures were similar to those found in torsion and equal channel angular pressing (ECAP). Date: Wednesday November 28, 2012 Time: 8:30 A.M. Place: ARMS 1021 Lisa Stacey Secretary/Development Assistant Purdue University School of Materials Engineering 765/494-4100