Papers by Author: Maria Teresa Pérez-Prado

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Authors: Ling Jiang, Maria Teresa Pérez-Prado, Oscar A. Ruano, M.E. Kassner
Abstract: The bond strength of ultrafine grained Zr with a grain size of 0.4 µm, fabricated by accumulative roll bonding (ARB), was assessed. The shear strength of the bond was estimated to be about 20% of the shear fracture strength of the as processed metal, a ratio significantly higher than that found in other materials processed by similar methods. The favorable degree of bonding achieved is attributed to the high ductility of Zr as well as to the high reductions used during the ARB process.
Authors: S.R. Barrabes, M.E. Kassner, Maria Teresa Pérez-Prado, E. Evangelista
Abstract: The micron-size grain refinement of pure a-zirconium obtained with elevated temperature tensile deformation was investigated. The development of low-misorientation subboundaries caused the serration of the original grain boundaries at low strains. The final microstructure (e.g. strains > 3) was predominantly composed of fine, equiaxed “crystallites” with ⅔ of the boundaries being of very low misorientations (< 3°) and the remaining ⅓ being high angle boundaries (θ > 8°, and typically 25-35°). Discontinuous dynamic recrystallization was excluded as a possible mechanism due to the absence of newly formed grain nuclei. The bimodal distribution of the crystallite or (sub)grain boundary misorientations is inconsistent with the occurrence of continuous dynamic recrystallization and rotational recrystallization. The continual thinning of the original grains, the serration of the high angle boundaries, the bimodal misorientation distribution of misorientations, ⅔ of boundaries of very low misorientations at high strains all strongly suggest geometric dynamic recrystallization and dynamic recovery as the grain refinement and restoration mechanisms.
Authors: J.A. del Valle, Maria Teresa Pérez-Prado, Oscar A. Ruano
Authors: Maria Teresa Pérez-Prado, F. Salort, Ling Jiang, Oscar A. Ruano, M.E. Kassner
Abstract: A coarse grained Zr-Hf alloy has been subjected to one rolling pass with different thickness reductions ranging from 10% to 80%. Rolling was performed at three temperatures: 300°C, room temperature (RT) and liquid nitrogen temperature (-196°C). It has been found that, with increasing strain per pass, i.e., with increasing strain rate, the deformation mechanism changes from twinning to dislocation slip. The minimum strain per pass necessary to trigger the transition in deformation mechanism decreases with decreasing temperature. High strain, high strain-rate deformation leads to the development of an ultrafine grained structure. Simultaneously, a basal type rolling texture forms. At the higher temperatures (RT and above) a recrystallization texture component is also present. Thus, nanostructuring of this Zr-Hf alloy during severe rolling is attributed to a combination of grain subdivision by the formation of geometrically necessary boundaries and to nucleation and growth phenomena taking place as a consequence of rapid adiabatic heating.
Authors: Maria Teresa Pérez-Prado, J.A. del Valle, Oscar A. Ruano
Authors: Maria Teresa Pérez-Prado, Joost J. Vlassak
Authors: Maria Teresa Pérez-Prado, Terry R. McNelley, G. González-Doncel, Oscar A. Ruano
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