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The Heat Treatment of Duralumin

Description: When certain light aluminum alloys are heat-treated, quenched and aged, there is considerable improvement in their tensile properties. This paper presents different methods of accomplishing these heat treatments.
Date: March 1927
Creator: Nelson, Wm.
Partner: UNT Libraries Government Documents Department

The Tensile Elastic Properties at Low Temperatures of 18:8 Cr-Ni Steel as Affected by Heat Treatment and Slight Plastic Deformation

Description: Note presenting the relationship between stress, strain, and permanent set for 18:8 Cr-Ni steel as measured at -110 degrees Fahrenheit. The influence of annealing and slight plastic extension upon the derived elastic properties is also discussed.
Date: July 1941
Creator: Mebs, R. W. & McAdam, D. J., Jr.
Partner: UNT Libraries Government Documents Department

Performance of as-forged, heat-treated, and overaged S-816 blades in a turbojet engine

Description: Report presenting an investigation to study the effects of several heat treatments on the operating life of turbine blades in a J33-33 turbojet engine operated without an afterburner. As-forged blades, blades solution treated at temperatures high enough to produce germinated grains, blades given a double-aging treatment, and blades overaged by overtemperature heat treatments are evaluated. Results regarding the engine operating results and blade performance, metallurgical studies of as-heat-treated specimens, and metallurgical studies of failed blades are provided.
Date: March 3, 1955
Creator: Weeton, J. W.; Clauss, F. J. & Johnston, J. R.
Partner: UNT Libraries Government Documents Department

Effect of heat treatment upon the microstructure and hardness of a wrought cobalt-base alloy stellite 21 (AMS 5385)

Description: Report presenting an investigation of the response of wrought Stellite 21, a typical cobalt-base alloy, to heat treatment. The alloy was solution-treated and transformed by aging and isothermal transformation at temperatures of 1200 to 1950 degrees Fahrenheit for periods of 5 minutes to 72 hours. Results regarding the solution-treated structure, precipitation by isothermal transformation, precipitation by aging, grain boundary behavior, and hardness are provided.
Date: March 1954
Creator: Clauss, F. J. & Weeton, J. W.
Partner: UNT Libraries Government Documents Department

Stress corrosion cracking behavior of Alloy 600 in high temperature water

Description: SCC susceptibility of Alloy 600 in deaerated water at 360 C (statically loaded U-bend specimens) is dependent on microstructure and whether the material was cold-worked and annealed (CWA) or hot-worked and annealed (HWA). All cracking was intergranular, and materials lacking grain boundary carbides were most susceptible to SCC initiation. CWA tubing materials are more susceptible to SCC initiation than HWA ring-rolled forging materials with similar microstructures (optical metallography). In CWA tubing materials, one crack dominated and grew to a visible size. HWA materials with a low hot-working finishing temperature (<925 C) and final anneals at 1010-1065 C developed both large cracks (similar to those in CWA materials) and small intergranular microcracks detectable only by destructive metallography. HWA materials with a high hot-working finishing temperature (>980 C) and a high-temperature final anneal (>1040 C), with grain boundaries that are fully decorated, developed only microcracks in all specimens. These materials did not develop large, visually detectable cracks, even after more than 300 weeks exposure. A low-temperature thermal treatment (610 C for 7h), which reduces or eliminates SCC in Alloy 600, did not eliminate microcrack formation in high temperature processed HWA materials. Conventional metallographic and analytical electron microscopy (AEM) were done on selected materials to identify the factors responsible for the observed differences in cracking behavior. Major difference between high-temperature HWA and low-temperature HWA and CWA materials was that the high temperature processing and final annealing produced predominantly ``semi-continuous`` dendritic M{sub 7}C{sub 3} carbides along grain boundaries with a minimal amount of intragranular carbides. Lower temperature processing produced intragranular M7C3 carbides, with less intergranular carbides.
Date: July 1, 1995
Creator: Webb, G.L. & Burke, M.G.
Partner: UNT Libraries Government Documents Department

A SUMMARY OF THE WORK ASSOCIATED WITH THE SOLUTION AND UNDERSTANDING OF STRINGER-TYPE CORROSION IN ZIRCALOY-2 AND -3

Description: This report summarizes the work performed to eliminate stringer-type corrosion from Zircaloy-2 and Zircaloy-3. The investigation included a study of the melting and fabrication variables of the alloys. Metallographic and thermal treatment studies identified the problem to be inert atmosphere melting. Based on this work, a stringer formation mechanism has been postulated. (auth)
Date: April 1, 1959
Creator: Goodwin, J.G.; Rubenstein, L.S.; Grozier, J.D. & Shubert, F.L.
Partner: UNT Libraries Government Documents Department

Loss of Radioactivity from Barium Carbonate Samples

Description: The exchange loss of radioactivity from solid samplos of barium carbonate through the agency of carbonic acid and its ions has been investigated under a variety of conditions. It is concluded that the losses observed are greatly dependent upon the method of sample preparation, in particular the nature or any heat treatment which the sample materials undergo.
Date: January 9, 1948
Creator: Yankwich, Peter E.
Partner: UNT Libraries Government Documents Department

Kinetics of phase growth in the Cu-Sn system and application to composite Nb3Sn strands

Description: Nb{sub 3}Sn is the superconductor most used in the R and D of high field accelerator magnets by either the wind and react or the react and wind technique. In order to program the low temperature steps of the heat treatment, the growth kinetics of Cu-Sn intermetallics was investigated as a function of duration and temperature. The diffusion constants of {eta}, {var_epsilon} and {delta} phases between 150 and 550 C were evaluated using Cu-Sn model samples. Statistical and systematic errors were thoroughly evaluated for an accurate data analysis. Next the behavior of Internal Tin and Modified Jelly Roll Nb{sub 3}Sn composites was compared with the model predictions.
Date: November 18, 2002
Creator: al.1, Emanuela Barzi et
Partner: UNT Libraries Government Documents Department

Empirical Prediction of Dimensional Stability of Natural Uranium Fuel Elements

Description: Since a theoretical mechanism to explain the change in dimensions of fuel elements during irradiation has not been proven to date, an empirical approach was evaluated. This report details results of a study, by multiple correlation techniques, of the dimensional behavior of 956 fuel elements that were divided into six different groups representing different heat treatments.
Date: February 14, 2003
Creator: LeGeros, J.P.
Partner: UNT Libraries Government Documents Department

Robocasting of Ceramics and Composites Using Fine Particle Suspensions

Description: Solid freeform fabrication is the near-net-shape manufacturing of components by sequentially stacking thin layers of material until complicated three dimensional shapes are produced. The operation is computer controlled and requires no molds. This exciting new field of technology provides engineers with the ability to rapidly produce prototype parts directly from CAD drawings and oftentimes little or no machining is necessary after fabrication. Techniques for freeform fabrication with several types of plastics and metals are already quite advanced and maybe reviewed in references 1 and 2. Very complicated plastic models can be fabricated by stereolithography, selective laser sintering, fused deposition modeling, or three-dimensional ink jet printing. Metals may be freeformed by the LENS{trademark} technique and porous ceramic bodies by three dimensional printing into a porous powder bed. However, methods for freeform fabrication that utilize particulate slurries to build dense ceramics and composites are not as well developed. The techniques that are being developed for the freeform fabrication of dense structural ceramics primarily revolve around the sequential layering of ceramic loaded polymers or waxes. Laminated Object Manufacturing and CAM-LEM processing use controlled stacking and laser cutting of ceramic tapes [2,3]. Similar to fused deposition modeling, ceramic loaded polymer/wax filaments are being used for the fused deposition of ceramics [2,4]. Extrusion freeform fabrication uses high pressure extrusion to deposit layers of ceramic loaded polymer/wax systems[1]. Modified stereolithographic techniques are also being developed using ceramic loaded ultraviolet curable resins [2]. Pre-sintered parts made with any of these techniques typically have 40-55 vol.% polymeric binder. In this regard, these techniques are analogous to powder injection molding of ceramics. Very long and complicated burnout heat treatments are necessary to produce a dense ceramic, free of organics. Heating rates of 0.2 degrees Celsius per minute are common. [5] Thus, while a part maybe rapidly prototype within a ...
Date: October 28, 1999
Creator: CESARANO III,JOSEPH
Partner: UNT Libraries Government Documents Department

Partitioning planning studies: Preliminary evaluation of metal and radionuclide partitioning the high-temperature thermal treatment systems

Description: A preliminary study of toxic metals and radionuclide partitioning during high-temperature processing of mixed waste has been conducted during Fiscal Year 1996 within the Environmental Management Technology Evaluation Project. The study included: (a) identification of relevant partitioning mechanisms that cause feed material to be distributed between the solid, molten, and gas phases within a thermal treatment system; (b) evaluations of existing test data from applicable demonstration test programs as a means to identify and understand elemental and species partitioning; and, (c) evaluation of theoretical or empirical partitioning models for use in predicting elemental or species partitioning in a thermal treatment system. This preliminary study was conducted to identify the need for and the viability of developing the tools capable of describing and predicting toxic metals and radionuclide partitioning in the most applicable mixed waste thermal treatment processes. This document presents the results and recommendations resulting from this study that may serve as an impetus for developing and implementing these predictive tools.
Date: March 1, 1997
Creator: Liekhus, K.; Grandy, J. & Chambers, A.
Partner: UNT Libraries Government Documents Department

The influence of carbon on the structure of preceramic polymer derived SiC

Description: The microstructure of SiC produced from allyl-hydridopolycarbosilane (AHPCS) was studied after thermal treatments at temperatures up to 1600 C. SiC samples were prepared in contact with pyrocarbon, carbon fiber, carbon felt, carbon powder, and graphite. Each of these configurations was examined using optical, scanning electron, and transmission electron microscopy. The resultant microstructure of the SiC in the vicinity of the carbon/graphite source was different for each sample. In some cases the grains were uniform, equiaxed and about the same size as SiC grains derived from neat AHPCS. Other samples exhibited accelerated grain growth in the vicinity of the carbon, and occasionally appeared to mimic the original carbon structure. Understanding and controlling such behavior will facilitate the fabrication of polymer derived stoichiometric SiC, and also has significant implications for the fabrication of SiC/SiC composites with a pyrocarbon interface and polymer derived matrix.
Date: January 1, 1997
Creator: Kolaya, L.E. & Lewis, N.
Partner: UNT Libraries Government Documents Department

Characterization of the solid low level mixed waste inventory for the solid waste thermal treatment activity - III

Description: The existing thermally treatable, radioactive mixed waste inventory is characterized to support implementation of the commercial, 1214 thermal treatment contract. The existing thermally treatable waste inventory has been identified using a decision matrix developed by Josephson et al. (1996). Similar to earlier waste characterization reports (Place 1993 and 1994), hazardous materials, radionuclides, physical properties, and waste container data are statistically analyzed. In addition, the waste inventory data is analyzed to correlate waste constituent data that are important to the implementation of the commercial thermal treatment contract for obtaining permits and for process design. The specific waste parameters, which were analyzed, include the following: ``dose equivalent`` curie content, polychlorinated biphenyl (PCB) content, identification of containers with PA-related mobile radionuclides (14C, 12 79Se, 99Tc, and U isotopes), tritium content, debris and non-debris content, container free liquid content, fissile isotope content, identification of dangerous waste codes, asbestos containers, high mercury containers, beryllium dust containers, lead containers, overall waste quantities, analysis of container types, and an estimate of the waste compositional split based on the thermal treatment contractor`s proposed process. A qualitative description of the thermally treatable mixed waste inventory is also provided.
Date: September 24, 1996
Creator: Place, B.G., Westinghouse Hanford
Partner: UNT Libraries Government Documents Department

Energy-efficient process for hot-dip batch galvanizing

Description: Hot-dip galvanizing of steel sheets, pipes, and other fabrication items is a popular method of corrosion protection. Currently, steel articles are immersed in molten zinc at 860{degrees}F, thereby forming a {open_quotes}frozen{close_quotes} metal (interfacial zinc iron intermetallic layer) on the surface. Drawbacks to the current technology include the expense of heating parts at such a high temperature and the generation of by-products such as zinc alloys, zinc oxides, and smoke. Furthermore, new federal regulations have significantly reduced acceptable lead levels in coatings, because lead from galvanized, coated steel will dissolve in water. Such dissolved lead may accumulate in human bodies with deleterious results. Additionally, the use of a molten salt layer on top of zinc (top-flux) causes kettle smoke and ash evolution. Ferro Technologies, Inc. has proposed a lead-free batch technology that will significantly improve the galvanizing process. The new Thermo Prep{trademark} process protects steel surfaces with a thermally stable flux by preheating parts to 400{degrees}F to 450{degrees}F in a separate furnace, and then immersing them in molten, lead-free zinc for a short period of time. The use of a thermally stable pre-flux would eliminate the need for top-flux, thereby reducing associated wastes.
Date: April 1, 1998
Partner: UNT Libraries Government Documents Department

Development of Ultrafine, Lamellar Structures in Two-Phase {gamma}-TiAl Alloys

Description: Processing of two-phase gamma-TiAl alloys (Ti-47Al-2Cr-2Nb or minor modifications thereof) above the alpha-transus temperature (T {sub alpha}) produced unique refined-colony/ultrafine lamellar structures in both powder- and ingot-metallurgy (P/M and I/M, respectively) alloys. These ultrafine lamellar structures consist of fine laths of the gamma and alpha {sub 2} phases, with average interlamellar spacings (lambda {sub Lambda}) of 100-200 nm and alpha {sub 2}-alpha {sub 2} spacings (lambda {sub alpha}) of 200-500 nm, and are dominated by gamma/alpha {sub 2} interfaces. This characteristic microstructure forms by extruding P/M Ti-47Al-2Cr-2Nb alloys above T {sub alpha}, and also forms with finer colony size but slightly coarser fully-lamellar structures by hot-extruding similar I/M alloys. Alloying additions of B and W refine lambda {sub L} and lambda {sub alpha} in both I/M Ti-47Al (cast and heat-treated above T {sub alpha}) or in extruded Ti-47Al-2Cr-2Nb alloys. The ultrafine lamellar structure in the P/M alloy remains stable during heat-treatment at 900 {degrees}C for 2h, but becomes unstable after 4h at 982 {degrees}C; the ultrafine lamellar structure remains relatively stable after aging for {gt}5000 h at 800 {degrees}C. Additions of B+W dramatically improve the coarsening resistance of lambda L and lambda alpha in the I/M Ti-47Al alloys aged for 168 h at 1000{degrees}C. In both the P/M and I/M Ti-47Al-2Cr-2Nb alloys, these refined-colony/ultrafine-lamellar structures correlate with high strength and good ductility at room temperature, and very good strength at high temperatures. While refining the colony size improves the room-temperature ductility, alloys with finer lambda {sub L} are stronger at both room- and high-temperatures. Additions of B+W produce finer as-processed lambda {sub L} and lambda {sub alpha} in I/M TiAl alloys, and stabilize such structures during heat-treatment or aging.
Date: December 1997
Creator: Maziasz, P. J.
Partner: UNT Libraries Government Documents Department

The development of straightness measuring equipment. Final report

Description: This report details work performed between Lockheed Martin Energy Systems, Inc. (LMES) and UTE Straight-O-Matic (UTE) under the National Machine Tool Partnership program. This work included the design and construction of an automatic straightness measuring system capable of retrofitting to existing machines. 1 fig.
Date: May 20, 1997
Creator: Demint, P.D. & Abraham, M.
Partner: UNT Libraries Government Documents Department

Reports of the measurement of elastic properties of 51XX series steels for the heat treatment distortion project

Description: We have measured the temperature dependence of the elastic constants of the 51XX series steels [gear steels] for a range of phases. At RT the normalized steel (pearlite) has the highest value of the moduli, the bainite phase the next highest, and martensite the lowest. Extrapolation of the austenite suggests that at RT austenite has lower moduli than martensite. For all the grades and phases of steels examined, the behavior of the elastic constants is similar: a curve could be drawn for each of the moduli from all the phases and all the grades would not deviate by more than {+-}4%. The normalized phase (100% pearlite in 5180) is stable up to 900 C. Bainite is stable up to 500 C. Martensite starts to change above 150 C as it tempers or strain relieves; once this is complete, the martensite moduli increase to similar values to bainite. Extrapolations are discussed. Behavior in lower carbon steels (5140, 5120) should conform to above; there is no explanation for the anomalous behavior of the quenched 5120 steel.
Date: September 1, 1997
Creator: Darling, T.; Migliori, A.; Armstrong, P.E.; Vaidya, R.; Scherer, C. & Lowe, T.
Partner: UNT Libraries Government Documents Department

Inhibition of stress corrosion cracking of Alloy X-750 by prestrain

Description: Tests of precracked and as-notched compact tension specimens were conducted in 3600C hydrogenated water to determine the effect of prestrain on the stress corrosion cracking (SCC) resistance of Alloy X-750 in the HTH, AH and HOA heat treated conditions. Prestraining is defined as the intentional application of an initial load (or strain) that is higher than the final test load. Prestrain was varied from 10% to 40% (i.e., the initial to final load ratios ranged from 1.1 to 1.4). Other variables included notch root radius, stress level and irradiation. Specimens were bolt-loaded to maintain essentially constant displacement conditions during the course of the test. The frequent heat up and cooldown cycles that were necessary for periodic inspections provided an opportunity to evaluate the effect of test variables on rapid low temperature crack propagation to which this alloy is subject. For Condition HTH, application of 20% to 40% prestrain either eliminates or significantly retards SCC initiation in as-notched specimens and the onset of crack growth in precracked specimens. In addition, this procedure reduces the propensity for low temperature crack growth during cooldown. Similar results were observed for precracked HOA specimens. Application of 20% prestrain also retards SCC in as-notched and precracked AH specimens, but the effects are not as great as in Condition HTH. Prestraining at the 10% level was found to produce an inconsistent benefit. In-reactor SCC testing shows that prestrain greatly improves the in-flux and out-of-flux SCC resistance of Condition HTH material. No SCC was observed in precracked specimens prestrained 30%, whereas extensive cracking was observed in their nonprestrain counterparts.
Date: March 1, 1997
Creator: Mills, W.J.; Lebo, M.R. & Kearns, J.J.
Partner: UNT Libraries Government Documents Department

Embrittlement of austenitic stainless steel welds

Description: The microstructure of type-308 austenitic stainless steel weld metal containing {gamma} and {delta} and ferrite is shown. Typical composition of the weld metal is Cr-20.2, Ni-9.4, Mn-1.7, Si-0.5, C-0.05, N-0.06 and balance Fe (in wt %). Exposure of austenitic stainless steel welds to elevated temperatures can lead to extensive changes in the microstructural features of the weld metal. On exposure to elevated temperatures over a long period of time, a continuous network of M{sub 23}C{sub 6} carbide forms at the austenite/ferrite interface. Upon aging at temperatures between 550--850 C, ferrite in the weld has been found to be unstable and transforms to sigma phase. These changes have been found to influence mechanical behavior of the weld metal, in particular the creep-rupture properties. For aging temperatures below 550 C the ferrite decomposes spinodally into {alpha} and {alpha}{prime} phases. In addition, precipitation of G-phase occurs within the decomposed ferrite. These transformations at temperatures below 550 C lead to embrittlement of the weld metal as revealed by the Charpy impact properties.
Date: December 31, 1997
Creator: David, S.A. & Vitek, J.M.
Partner: UNT Libraries Government Documents Department

Fabrication of stable, large-area thin-film CdTe photovoltaic modules. Final subcontract report, May 10, 1991--February 28, 1995

Description: During the period of this subcontract, May 1991 through February 1995, Solar Cells, Inc. has developed and demonstrated a low-cost process to fabricate stable large-area cadmium telluride based thin-film photovoltaic modules. This report summarizes the final phase of the project which is concentrated on process optimization and product life tests. One of the major post-deposition process steps, the CdCl{sub 2} heat treatment, has been experimentally replaced with alternative treatments with vapor chloride or chlorine gas. Material and device qualities associated with alternative treatments are comparable or superior to those with the conventional treatment. Extensive experiments have been conducted to optimize the back-electrode structure in order to ensure long term device stability. Numerous small-area cells and minimodules have been subjected to a variety of stress tests, including but not limited to continuous light soak under open or short circuit or with resistive load, for over 10,000 hours. Satisfactory stability has been demonstrated on 48 cm{sup 2} and 64 cm{sup 2} minimodules under accelerated tests and on 7200 cm{sup 2} large modules under normal operating conditions. The conversion efficiency has also been significantly improved during this period. The total area efficiency of 7200 cm{sup 2} module has reached 8.4%, corresponding to a 60.3W normalized output; the efficiency of 64 cm{sup 2} minimodules and 1.1 cm{sup 2} cells has reached 10.5% (aperture area) and 12.4% (total area), respectively.
Date: June 1, 1995
Creator: Zhou, T.X.
Partner: UNT Libraries Government Documents Department

Electromagnetic Heating Methods for Heavy Oil Reservoirs

Description: The most widely used method of thermal oil recovery is by injecting steam into the reservoir. A well-designed steam injection project is very efficient in recovering oil, however its applicability is limited in many situations. Simulation studies and field experience has shown that for low injectivity reservoirs, small thickness of the oil-bearing zone, and reservoir heterogeneity limits the performance of steam injection. This paper discusses alternative methods of transferring heat to heavy oil reservoirs, based on electromagnetic energy. They present a detailed analysis of low frequency electric resistive (ohmic) heating and higher frequency electromagnetic heating (radio and microwave frequency). They show the applicability of electromagnetic heating in two example reservoirs. The first reservoir model has thin sand zones separated by impermeable shale layers, and very viscous oil. They model preheating the reservoir with low frequency current using two horizontal electrodes, before injecting steam. The second reservoir model has very low permeability and moderately viscous oil. In this case they use a high frequency microwave antenna located near the producing well as the heat source. Simulation results presented in this paper show that in some cases, electromagnetic heating may be a good alternative to steam injection or maybe used in combination with steam to improve heavy oil production. They identify the parameters which are critical in electromagnetic heating. They also discuss past field applications of electromagnetic heating including technical challenges and limitations.
Date: May 1, 2000
Creator: Sahni, A.; Kumar, M. & Knapp, R.B.
Partner: UNT Libraries Government Documents Department