Sean R. Agnew
University of Virginia
Ultimate tensile strengthDislocationComposite materialHardening (metallurgy)MetallurgyMaterials scienceDeformation mechanismCondensed matter physicsMagnesium alloyAlloyElectron backscatter diffractionTexture (crystalline)Slip (materials science)MagnesiumCrystal twinningNeutron diffractionPlasticityCrystallographyAnisotropyMicrostructure
201Publications
54H-index
13kCitations
Publications 197
Newest
Strategies for efficient and reliable texture measurements have been explored using the Nanoscale Ordered Materials Diffractometer (NOMAD) at the Spallation Neutron Source located at Oak Ridge National Laboratory (ORNL). To test these strategies, the texture of an Al alloy was also investigated using another neutron diffraction instrument, a constant-wavelength neutron diffractometer (NRSF2) located at the High Flux Isotope Reactor, also at ORNL. Reasonable agreement was found across the two exp...
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#1Mohammed A. Shabana (UVA: University of Virginia)H-Index: 1
#2Jishnu J. Bhattacharyya (UVA: University of Virginia)H-Index: 13
Last. Sean R. Agnew (UVA: University of Virginia)H-Index: 54
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Abstract The principle of “stress equivalence” proposed by Basinski et al. offers insight regarding the nature of thermally activated plasticity of solid solution alloys of FCC and HCP (Mg) crystal structures at low temperatures. More recently, Leyson and Curtin have developed a theoretical framework which builds upon the Labusch solute strengthening model. The current work analyzes some recent results from the literature (for single crystal Mg-Zn, Mg-Y, and Mg-Dy) which permit a further examina...
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#1Jishnu J. Bhattacharyya (UVA: University of Virginia)H-Index: 13
#2Sriramya Nair (Cornell University)H-Index: 8
Last. Sean R. Agnew (UVA: University of Virginia)H-Index: 54
view all 7 authors...
Abstract The elastoplastic transition of a metastable β-Ti alloy, Timetal-18, is studied using in-situ high energy synchrotron X-ray diffraction microscopy (HEDM). The measured evolutions of the complete elastic strain (and stress) tensor(s), resolved shear stress, lattice rotation and rotation of the stress state of the grains are compared with the predictions of the elasto-viscoplastic Micromechanical Analysis of Stress-Strain Inhomogeneities with fast Fourier transform (MASSIF) code instantia...
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#1Michael A. RitzoH-Index: 1
#2Sean R. AgnewH-Index: 54
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Last. Sean R. AgnewH-Index: 54
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1 CitationsSource
#1N.E. Peterson (UVA: University of Virginia)
#2D. Malta (UVA: University of Virginia)
Last. Sean R. Agnew (UVA: University of Virginia)H-Index: 54
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Abstract Exploring the effects of minor ternary alloying additions, typically impurity elements, on the phase stability of U-10Mo is important for preventing undesirable phase decomposition during processing or during service. This work examines the influence small ternary additions of Cr, Ni, and Co. Both in-situ and ex-situ neutron diffraction measurements made during and after high temperature (450 – 525°C) exposures were used to better define the influence of these elements on the time-tempe...
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#1Zachary D. Harris (UVA: University of Virginia)H-Index: 8
#2Michael A. Ritzo (UVA: University of Virginia)H-Index: 1
Last. James T. Burns (UVA: University of Virginia)H-Index: 16
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Abstract Uniaxial tensile experiments on hydrogen-charged and non-charged polycrystalline nickel deformed to a true plastic strain of ~0.1 at room temperature and 77 K reveal that hydrogen has no measurable effect on texture evolution. Texture measurements were completed on samples of each condition, as well as an as-received reference specimen, using electron backscatter diffraction data collected from >20,000 individual grains. Crystal plasticity simulations support the conclusion that the sim...
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#1Fulin Wang (UVA: University of Virginia)H-Index: 10
#2Yejun Gu (Johns Hopkins University)H-Index: 6
Last. Sean R. Agnew (UVA: University of Virginia)H-Index: 54
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Abstract Consideration of published TEM and molecular dynamics studies of interactions between matrix dislocations and { 10 1 ¯ 2 } twin boundaries (TB) in hexagonal close packed metals inspires a hypothesis regarding the formation of dislocations with Burgers vectors inside the twins. It was previously reported that when basal dislocations from the matrix are swept by an advancing TB, they are converted into partial dislocations bounding basal I1 stacking faults (SFs) within the twin. In the pr...
1 CitationsSource
#1Jishnu J. Bhattacharyya (UVA: University of Virginia)H-Index: 13
#2Sriramya Nair (Cornell University)H-Index: 8
Last. Sean R. Agnew (UVA: University of Virginia)H-Index: 54
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ABSTRACT In the present work, the elastic behavior of a metastable β-Ti alloy, Timetal-18, is studied in the β-quenched condition using in-situ far-field (ff) and near-field (nf) high energy synchrotron X-ray diffraction microscopy (HEDM) techniques and full-field crystal elasticity simulation. HEDM enables assessment of the 3D microstructure as well as the complete (6 components) elastic strain tensor and crystallographic orientation of each grain in the gauge volume of a polycrystalline aggreg...
3 CitationsSource
#1Maria-Teresa Pérez-Prado (IMDEA)H-Index: 1
#2Jan BohlenH-Index: 27
Last. Nicole Stanford (UniSA: University of South Australia)H-Index: 42
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Scientific understanding of the behavior of wrought magnesium alloys is quite mature, with literally thousands of papers published on the topic, along with several reviews. Most of this research is relatively recent, being published after the year 2000. With such a large body of work available to the reader, it could easily be missed that the field of magnesium metallurgy is poised for significant advances. Access to synchrotron and neutron scattering has revealed new knowledge about deformation...
3 CitationsSource