Papers by Michael V Glazoff
Idaho National Laboratory (INL) has an ongoing project that supports the development of high-temp... more Idaho National Laboratory (INL) has an ongoing project that supports the development of high-temperature electrolysis for efficient hydrogen production from steam using solid oxide electrolysis cells (SOECs). To accomplish this objective, technical and degradation issues associated with the SOECs must be addressed. This report covers various approaches being pursued to model degradation issues in SOECs.
The goal of next generation reactors is to increase energy efficiency in the production of electr... more The goal of next generation reactors is to increase energy efficiency in the production of electricity and provide high-temperature heat for industrial processes. The efficient transfer of energy for industrial applications depends on the ability to incorporate effective heat exchangers between the nuclear heat transport system and the industrial process. The need for efficiency, compactness, and safety challenge the boundaries of existing heat exchanger technology. Various studies have been performed in attempts to update the secondary heat exchanger that is downstream of the primary heat exchanger, mostly because its performance is strongly tied to the ability to employ more efficient industrial processes. Modern compact heat exchangers can provide high compactness, a measure of the ratio of surface area-to-volume of a heat exchange. The microchannel heat exchanger studied here is a plate-type, robust heat exchanger that combines compact-ness, low pressure drop, high effectiveness, and the ability to operate with a very large pressure differential between hot and cold sides. The plates are etched and thereafter joined by diffusion welding, resulting in extremely strong all-metal heat exchanger cores. After bonding, any number of core blocks can be welded together to provide the required flow capacity. This study explores the microchannel heat exchanger and draws conclusions about diffusion welding/bonding for joining heat exchanger plates, with both experimental and computational modeling, along with existing challenges and gaps. Also, presented is a thermal design method for determining overall design specifications for a microchannel printed circuit heat exchanger for both supercritical (24 MPa) and subcritical (17 MPa) Rankine power cycles.
A general asymmetric yield function is proposed with dependence on the stress invariants for pres... more A general asymmetric yield function is proposed with dependence on the stress invariants for pressure sensitive metals. The pressure sensitivity of the proposed yield function is consistent with the experimental result of Spitzig and Richmond (1984) for steel and aluminum alloys while the asymmetry of the third invariant is preserved to model strength differential (SD) effect of pressure insensitive materials. The proposed yield function is transformed in the space of the stress triaxaility, the von Mises stress and the normalized invariant to theoretically investigate the possible reason of the SD effect. The proposed plasticity model is further extended to characterize the anisotropic behavior of metals both in tension and compression. The extension of the yield function is realized by introducing two distinct fourth-order linear transformation tensors of the stress tensor for the second and third invariants, respectively. The extended yield function reasonably models the evolution of yield surfaces for a zirconium clock-rolled plate during in-plane and through-thickness compression reported by Plunkett et al. (2007). The extended yield function is also applied to describe the orthotropic behavior of a face-centered cubic metal of AA 2008-T4 and two hexagonal close-packed metals of high-purity a-titanium and AZ31 magnesium alloy. The orthotropic behavior predicted by the generalized model is compared with experimental results of these metals. The comparison validates that the proposed yield function provides sufficient predictability on SD effect and anisotropic behavior both in tension and compression. When it is necessary to consider r-value anisotropy, the proposed function is efficient to be used with non-associated flow plasticity by introducing a separate plastic potential for the consideration of r-values as shown in Stoughton and Yoon (2004, 2009).
Casting Aluminum Alloys, 2007
Casting Aluminum Alloys, 2007
The present invention consists of an Al-Ni-Mn based alloy for die casting, squeeze casting, perma... more The present invention consists of an Al-Ni-Mn based alloy for die casting, squeeze casting, permanent mold casting, sand casting and/or semi-solid metal forming. Preferred embodiments of this alloy include the following compositional additions, all in weight percent: about 0.5-6% Ni, about 1-3% Mn, less than about 1% Fe, less than about 1% Si, less than about 0.3% Ti, and less than about 0.06% B, the balance Al, incidental elements and impurities. On a more preferred basis, this alloy composition consists essentially of about 3.5-4.5% Ni, about 1.5-2.5% Mn, less than about 0.1% Fe, less than about 0.1% Si, less than about 0.15% Ti, and less than about 0.03% B, the balance A1 and incidentals.
In the post-Fukushima world, the thermal and structural stability of materials under extreme cond... more In the post-Fukushima world, the thermal and structural stability of materials under extreme conditions is an important issue for the safety of nuclear reactors. Because the nuclear industry is going to continue using advanced zirconium cladding materials in the foreseeable future, it becomes critical to gain fundamental understanding of the several interconnected problems. First, what are the thermodynamic and kinetic factors affecting the oxidation and hydrogen pick-up by these materials at normal, off-normal conditions, and in long-term storage? Secondly, what protective coatings (if any) could be used in order to gain extremely valuable time at off-normal conditions, e.g., when temperature exceeds the critical value of ~1200°C (2200° F)? Thirdly, the kinetics of oxidation of such protective coating or braiding needs to be quantified. Lastly, even if some degree of success is achieved along this path, it is absolutely critical to have in-service inspection algorithms allowing identifying defects of cladding as soon as possible.
Russian Journal of Physical Chemistry
ABSTRACT
Russian Journal of Physical Chemistry
ABSTRACT
Metallofizika i noveĭshie tekhnologii
ABSTRACT
Thermally stable transitional alumina retaining high specific surface area after calcination at 1... more Thermally stable transitional alumina retaining high specific surface area after calcination at 1000 C, suitable for the use as catalysts or catalytic supports are produced by treating an aqueous solution containing Al+3 and optionally a doping amount of La+3 (e.g., 0.3 mol.%) with an anion exchange rasin to give a stable hydroxide sol followed by freeze drying of the sol and further thermal dehydration. The resultant stabilized transitional alumina retains high specific surface area at 1000 C, and additionally stabilization is achieved with a very low level of added La.
This technical evaluation (TEV) has been prepared to evaluate the possibility of the formation of... more This technical evaluation (TEV) has been prepared to evaluate the possibility of the formation of explosive and/or highly toxic substances during molten salt pyrolysis of oil residue. It particular, it addresses the possibility of a self-sustained chemical reaction developing in the reactor due to the potential formation of the sodium vapor, highly energetic nitrogen-bearing compounds (e.g., azides), and the influence of the trace amounts of heavy metals (inevitably present in any oil residue) upon these chemical reactions. For chemistry evaluation, standard thermodynamic calculations were conducted using the software ThermoCalc Software AB (Stockholm, Sweden) along with the commercial thermodynamic databases from ThermoCalc Software AB and the ThermoTech Inc. (University of Cambridge, UK). These calculations were validated by comparing the computed values of the Gibbs thermodynamic potentials to the existing reliable experimental data for a number of chemical processes in different...
Zirconium-based alloys Zircaloy-2 and Zircaloy-4 are widely used in the nuclear industry as cladd... more Zirconium-based alloys Zircaloy-2 and Zircaloy-4 are widely used in the nuclear industry as cladding materials for light water reactor (LWR) fuels. These materials display a very good combination of properties such as low neutron absorption, creep behavior, stress-corrosion cracking resistance, reduced hydrogen uptake, corrosion and/or oxidation, especially in the case of Zircaloy-4. However, over the last couple of years energetic efforts have been undertaken to improve fuel clad oxidation resistance during off-normal temperature excursions. Efforts have also been made to improve upon the already achieved levels of mechanical behavior and reduce hydrogen uptake. In order to facilitate the development of such novel materials, it is very important to achieve not only engineering control, but also a scientific understanding of the underlying material degradation mechanisms, both in working conditions and in storage of used nuclear fuel.
Le Journal de Physique IV, 1993
Molecular Dynamics simulations of edge dislocation mobility under stress in ordered L12 Ni3AI hav... more Molecular Dynamics simulations of edge dislocation mobility under stress in ordered L12 Ni3AI have been performed between 10K and IOOOK, and at applied shear stresses ranging from 0.01 to 0.08 Cqq. In this way it has been possible to determine the Peierls stress and mobility parameters as a function of stress and temperature. <001>{100) edge dislocations were studied, which split into closely spaced partials under stress. Under all levels of applied stress (and at lower temperatures) the initial partial dislocations would intermittently stop moving and recombine, then dissociate and move again. In all cases the dislocations exhibited a soliton-like behavior: infinite acceleration at the onset of movement, and hrther movement at a steady velocity (which was only weakly dependent on stress) on the order of 25% of the acoustic shear velocity . Nonclassical, highly non-linear behavior was observed indicating the probability that a soliton picture of dislocation motion is more appropriate than the classical, "massive string" model that is traditionally used. Furthermore, as both the temperature and the stress were increased, dislocation multiplication became increasingly frequent, ultimately resulting in a spontaneous amorphisation transition which has signs of being a percolation process.
MRS Proceedings, 2002
We employ a combination of Z-contrast scanning transmission electron microscopy (Z-STEM) and firs... more We employ a combination of Z-contrast scanning transmission electron microscopy (Z-STEM) and first-principles density-functional calculations to investigate the interaction between metal atoms and cubic alumina catalytic supports. We show that there are two observed La sites at the porous γalumina surface, and that single La atoms do not exhibit a tendency to cluster. Cr behaves very differently from La -it has a tendency to cover the alumina surface in ordered, periodic raft-like patches. The degradation of the chromia/alumina catalyst is related to the possibility for the chromium to move away from the surface into the bulk, and the activation barrier for such a process is higher in ηalumina than in γalumina, i.e., ηalumina is a more durable support for chromium catalyst.
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Papers by Michael V Glazoff