Author
Bjørn Clausen
Other affiliations: Ohio State University, California Institute of Technology, Colorado State University ...read more
Bio: Bjørn Clausen is an academic researcher from Los Alamos National Laboratory. The author has contributed to research in topics: Neutron diffraction & Residual stress. The author has an hindex of 48, co-authored 251 publications receiving 7930 citations. Previous affiliations of Bjørn Clausen include Ohio State University & California Institute of Technology.
Papers published on a yearly basis
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TL;DR: In this article, the twinning and detwinning behavior in a strongly textured magnesium alloy was investigated using in situ neutron diffraction during the cyclic deformation along the prior extrusion direction at the fully reversed total constant strain amplitude of 1.2% at room temperature.
455 citations
TL;DR: In this paper, a study of the mechanical response of Mg AZ31 when deformed under twinning dominated conditions is presented, and it is concluded that the texture variation due to twinning is sufficient to explain the observed macroscopic stress-strain response.
410 citations
TL;DR: In this paper, a family of transformation-induced plasticity (TRIP) steels with varying retained austenite contents was used to produce a series of transformation induced plasticity steels for cold-rolled 0.1C-7.1Mn steel.
Abstract: Manganese enrichment of austenite during prolonged intercritical annealing was used to produce a family of transformation-induced plasticity (TRIP) steels with varying retained austenite contents. Cold-rolled 0.1C-7.1Mn steel was annealed at incremental temperatures between 848 K and 948 K (575 °C and 675 °C) for 1 week to enrich austenite in manganese. The resulting microstructures are comprised of varying fractions of intercritical ferrite, martensite, and retained austenite. Tensile behavior is dependent on annealing temperature and ranged from a low strain-hardening “flat” curve to high strength and ductility conditions that display positive strain hardening over a range of strain levels. The mechanical stability of austenite was measured using in-situ neutron diffraction and was shown to depend significantly on annealing temperature. Variations in austenite stability between annealing conditions help explain the observed strain hardening behaviors.
310 citations
TL;DR: In this paper, the elastic macrostrains calculated from lattice parameter changes in Rietveld refinements are almost identical to the bulk elastic response and are comparable to the response obtained from a single lattice reflection typically used by practitioners at a steady state source.
Abstract: Macrostrain variations in engineering components are frequently examined using neutron diffraction, at both reactors and pulsed sources. It is desirable to minimize the sampling volume in order to maximize the spatial resolution, although this increases the required measurement time. At reactors, macrostrain behavior is inferred from a single lattice reflection (deemed to be representative of the bulk response). At a pulsed source, a complete diffraction pattern is recorded and accordingly it is natural to fit the entire diffraction spectra using a Rietveld [J. Appl. Cryst. 2, 65 (1969)] refinement. This means that an idealized crystal structure is fit to the measured distorted crystal structure, which includes deviation of the measured lattice reflections from the ideal due to elastoplastic strain anisotropies, which are dependent on the particular lattice reflection (hkl) considered. We show that elastic macrostrains calculated from lattice parameter changes in Rietveld refinements (without accounting for hkl dependent anisotropies) are almost identical to the bulk elastic response and are comparable to the response obtained from a single lattice reflection typically used by practitioners at a steady state source. Moreover good refinements on the complete pattern are obtained with short measurement times compared to what is required for good statistics for single reflections. By incorporating a description of the elastic strain anisotropy expected in cubic materials into the Rietveld code, an empirical prediction of plastic strain history is possible. The validity of these arguments is demonstrated by analysis of a uniaxial tensile load test and a reanalysis of previously reported data taken on a deformed stainless steel ring. The plastic strain predictions compare favorably with a finite element model.
301 citations
15 Jan 1999-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, applied and residual lattice strains were determined by neutron diffraction during a tensile test of a weakly textured austenitic stainless steel and were compared to the predictions of a self-consistent polycrystal deformation model.
Abstract: Applied and residual lattice strains were determined by neutron diffraction during a tensile test of a weakly textured austenitic stainless steel and were compared to the predictions of a self-consistent polycrystal deformation model. Parallel to the tensile axis the model predictions are generally within the resolution of the diffraction measurements, but perpendicular to the tensile axis discrepancies are noted. Discrepancies between model and measurements were greater for the residual lattice strains than during loading. It is postulated that this is because the model does not predict reverse plasticity during unload.
265 citations
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TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.
Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …
33,785 citations
TL;DR: The concept of high entropy introduces a new path of developing advanced materials with unique properties, which cannot be achieved by the conventional micro-alloying approach based on only one dominant element as mentioned in this paper.
4,394 citations
TL;DR: In this paper, a review of recent advances in understanding the mechanical behavior of metallic glasses, with particular emphasis on the deformation and fracture mechanisms, is presented, where the role of glass structure on mechanical properties, and conversely, the effect of deformation upon glass structure, are also described.
2,858 citations
01 Jan 2007
TL;DR: The Third edition of the Kirk-Othmer encyclopedia of chemical technology as mentioned in this paper was published in 1989, with the title "Kirk's Encyclopedia of Chemical Technology: Chemical Technology".
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2,666 citations