Thermodynamics and kinetics of grain boundaries in ultra fine grained copper produced by severe plastic deformation

1 List of symbols and abbreviations 3 Chapter 1: INTRODUCTION 6 Chapter 2: LITERATURE SURVEY 8 2.1: The essence of ultra fine grained materials 8 2.2: Severe plastic deformation: a method for producing UFG microstructure 11 2.3: Physical properties of materials derived from GB character 15 2.4: Non-equilibrium GBs: theoretical aspects 16 2.4.1: Conventional models for GB structure 16 2.4.2: Modeling of non-equilibrium GBs 19 2.4.3: Relaxation of the non-equilibrium state 22 2.4.3.1. The approach of Lojkowski 23 2.4.3.2. The approach of Varin & Kurzydłowski 24 2.4.3.3. The approach of Sangal & Tangri 25 2.5: Experimental observations 28 2.5.1: Measurements of diffusion in UFG materials 28 2.5.2: Characterization of UFG materials by X-ray diffraction 30 2.5.3: Utilization of Differential Scanning Calorimetry for UFG materials 31 2.6: Summary and research goals 33 Chapter 3: EXPERIMENTAL METHODS 35 3.1: Research methodology 35 3.1.1: Selection of the alloys 35 3.1.2: Preparation of samples: ECAP and surface treatment 37 3.1.3: Design of diffusion experiments 37 3.1.4: Thermal GB grooving for measurements of the relative GB energy 41 3.1.5: Microstructure characterization 43 3.2: Experimental techniques 44 3.2.1: Transmission Electron Microscopy (TEM) 44 3.2.2: High-resolution Scanning Electron Microscopy (HRSEM) 44 3.2.3: Focused Ion Beam (FIB) 45 3.2.4: The Radiotracer technique for diffusion measurements 45 3.2.5: Secondary Ion Mass Spectroscopy (SIMS) 46 3.2.6: Electron Dispersive Spectroscopy (EDS) in the STEM 46 3.2.7: Atomic Force Microscopy (AFM): 47 3.2.8: Orientation Imaging Microscopy (OIM) 47