Author
A. Morawiec
Bio: A. Morawiec is an academic researcher from Carnegie Mellon University. The author has contributed to research in topics: Grain boundary & Misorientation. The author has an hindex of 6, co-authored 8 publications receiving 449 citations.
Papers
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TL;DR: In this paper, a semi-automated method has been used to measure all five macroscopically observable parameters of 4.1×10 6 boundary plane segments making up 5.4 mm 2 of boundary area in a hot-pressed magnesia polycrystal.
262 citations
TL;DR: In this article, the authors measured all five macroscopically observable degrees of freedom of 41 × 106 boundary plane segments making up 52 × 106μm2 of grain boundary interface area in a magnesia polycrystal and demonstrated that not all grain boundary configurations occur with the same frequency and that the relative free energies of the different interfacial configurations influence the population distribution.
Abstract: The multiplicity of distinct grain boundary configurations in polycrystals has made it difficult to determine the relative frequency with which each configuration is adopted As a result, the physiochemical properties of each boundary and the influence of the distribution of boundaries on macroscopic materials properties are not well understood Using a semiautomated system, we have measured all five macroscopically observable degrees of freedom of 41 × 106 boundary plane segments making up 52 × 106μm2 of grain boundary interface area in a magnesia polycrystal Our observations demonstrate that not all grain boundary configurations occur with the same frequency and that the relative free energies of the different interfacial configurations influence the population distribution Furthermore, the results indicate that relative grain boundary energies can be estimated based on the free surface energies
74 citations
TL;DR: In this article, a numerical method for reconstructing the grain boundary energy distribution over the complete space of macroscopic boundary parameters is presented, based on the analysis of the dihedral angles between homophase grain boundaries of polycrystalline triple junctions.
61 citations
TL;DR: In this article, a finite series of symmetrized spherical harmonics has been used to approximate the misorientation dependence of the relative grain boundary energy, and best fit coefficients for this series were determined by assuming that the interfacial tensions at each triple junction are balanced.
Abstract: Geometric and crystallographic data obtained from a well annealed magnesia polycrystal have been used to specify the five macroscopic degrees of freedom for 4665 grain boundaries. The results indicate, that for this sample, the five parameter grain boundary character space is fully occupied. A finite series of symmetrized spherical harmonics has been used to approximate the misorientation dependence of the relative grain boundary energy. Best fit coefficients for this series were determined by assuming that the interfacial tensions at each triple junction are balanced. The grain boundary energy function shows Read-Shockley behavior at small misorientations and a broad minimum near the Σ3 misorientation. Furthermore, misorientations about the ‹100› axis create boundaries with relative energies that are less than those created by misorientations about the ‹110› or ‹111› axes.
44 citations
TL;DR: A new experimental approach to the quantitative characterization of polycrystalline microstructure by scanning electron microscopy by combining automated electron backscattering diffraction with conventional scanning contrast imaging and with calibrated serial sectioning, which recovers precision estimates of the 3D idealized aggregate function G(x).
20 citations
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01 Jan 2000
TL;DR: In this article, the authors present a framework for the automated backscatter diffraction in scanning and transmission Electron Microscopy (EBSD) using three-dimensional orientations.
Abstract: List of Contributors. 1. The Development of Automated Diffraction in Scanning and Transmission Electron Microscopy D.J. Dingley. 2. Theoretical Framework for Electron Backscatter Diffraction V. Randle. 3. Representation of Texture in Orientation Space K. Rajan. 4. Rodriques-Frank Representations of Crystallographic Texture K. Rajan. 5. Fundamentals of Automated EBSD S.I. Wright. 6. Studies on the Accuracy of Electron Backscatter Diffraction Measurements M.C. Demirel, B.S. El-Dasher, B.L. Adams, A.D. Rollett. 7. Phase Identification Using Electron Backscatter Diffraction in the Scanning Electron Microscope J.R. Michael. 8. Three-Dimensional Orientation Imaging D.J. Jensen. 9. Automated Electron Backscatter Diffraction: Present State and Prospects R.A. Schwarzer. 10. EBSD: Buying a Systems A. Eades. 11. Hardware and Software Optimization for Orientation Mapping and Phase Identification P.P. Camus. 12. An Automated EBSD Acquisition and Processing System P. Rolland, K.G. Dicks. 13. Advanced Software Capabilities for Automated EBSD S.I. Wright, D.P. Field, D.J. Dingley. 14. Strategies for Analysis of EBSD Datasets W.E. King, J.S. Stolken, M. Kumar, A.J. Schwartz. 15. Structure-Property Relations: EBSD-Based Materials-Sensitive Design B.L. Adams, B.L. Henrie, L.L. Howell, R.J. Balling. 16. Use of EBSD Data in Mesoscale Numerical Analyses R. Becker, H. Weiland. 17. Characterization of Deformed Microstructures D.P. Field, H. Weiland. 18. Anisotropic Plasticity Modeling Incorporating EBSD Characterization of Tantalum and Zirconium J.F. Bingert, G.C. Kaschner, T.A. Mason, P.J. Maudlin, G.T. Gray III. 19. Measuring Strains Using Electron Backscatter Diffraction A.J. Wilkinson. 20. Mapping Residual Plastic Strain in Materials Using Electron Backscatter Diffraction E.M. Lehockey, Yang-Pi Lin, O.E. Lepik. 21.EBSD Contra TEM Characterization of a Deformed Aluminum Single Crystal Xiaoxu Huang, D.J. Jensen. 22. Continuous Recrystallization and Grain Boundaries in a Superplastic Aluminum Alloy T.R. McNelley. 23. Analysis of Facets and Other Surfaces Using Electron Backscatter Diffraction V. Randle. 24. EBSD of Ceramic Materials J.K. Farrer, J.R. Michael, C.B. Carter. 25. Grain Boundary Character Based Design of Polycrystalline High Temperature Superconducting Wires A. Goyal. Index.
1,443 citations
TL;DR: The absolute grain boundary mobility of 388 nickel grain boundaries was calculated using a synthetic driving force molecular dynamics method; complete results appear in the Supplementary materials as discussed by the authors. But the authors did not consider the effect of boundary mobility on grain boundary roughening.
646 citations
TL;DR: In this article, the fundamental concepts of grain boundary engineering (GBE) accompanied by a critical appraisal of GBE investigations are reported, and several variants on processing route schedules to produce successfully a GBE microstructure with improved properties.
559 citations
TL;DR: A review of grain boundary energy anisotropy can be found in this paper, with a brief discussion of the role of the grain boundary energies in nucleating discontinuous transitions in grain boundary structure and chemistry known as complexion transitions.
Abstract: This paper reviews findings on the anisotropy of the grain boundary energies. After introducing the basic concepts, there is a discussion of fundamental models used to understand and predict grain boundary energy anisotropy. Experimental methods for measuring the grain boundary energy anisotropy, all of which involve application of the Herring equation, are then briefly described. The next section reviews and compares the results of measurements and model calculations with the goal of identifying generally applicable characteristics. This is followed by a brief discussion of the role of grain boundary energies in nucleating discontinuous transitions in grain boundary structure and chemistry, known as complexion transitions. The review ends with some questions to be addressed by future research and a summary of what is known about grain boundary energy anisotropy.
366 citations