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High-Temperature Oxidation Resistance of Thin Iron-Chromium-Aluminum Alloy Sheet

Description: Abstract: "The oxidation resistance of thin sheets of iron-28 w/o chromium-2.67 to 10.0 w/o alloys, nominally 0.004, 0.006, 0.008, 0.012, and 0.016 in. thick, was determined by exposure in static air for 100 hr at 2100 and 2300 F. A minimum of 3.67 and 9.37 w/o aluminum was necessary to prevent excessive oxidation of 0.004-in.-thick sheet material at 2100 and 2300 F, respectively. Correspondingly, specimens of lower aluminum content and greater thickness withstood the oxidation attack. Oxidation of iron-chromium-aluminum alloys appeared to be related to the diffusion of aluminum to surfaces of the sheet to form an adherent protective layer of Al2O3."
Date: October 22, 1957
Creator: Jablonowski, Edward J.; Shober, Frederic R. & Dickerson, Ronald F.
Partner: UNT Libraries Government Documents Department

Effect of heat treatment temperature on creep-rupture properties of Fe{sub 3}Al-based alloys

Description: The effects of heat treatment at 1100 to 1250C on the creep-rupture properties of an Fe{sub 3}Al-based alloy were studied. Tests were conducted at 593C (1100F) and 207 MPa (30 ksi) in air. The modes of fracture were identified using optical metallography and scanning electron microscopy. Analytical electron microscopy was also used to study characteristics of the microstructure, including dislocations, ordered domains, and precipitates. The creep results showed maximum creep-rupture resistance with a heat treatment at approximately 1150C, with significant decreases in rupture life after heat treatments at both lower and higher temperatures. The peak in creep life was associated with fine precipitates that were observed after the 1150C heat treatment and persisted during prolonged creep at 593C. Heat treatment at 1150C appeared to cause dissolution of coarser precipitates which then reprecipitated as new fine particles upon cooling or during creep. These fine precipitates then pinned dislocations and grain boundaries to produce strength during creep.
Date: September 1, 1994
Creator: McKamey, C. G. & Maziasz, P. J.
Partner: UNT Libraries Government Documents Department

Thermal Conductivity of Uranium-Chromium and Uranium-Iron Eutectic Alloys

Description: Report discussing measurements of thermal conductivity and heat capacity for uranium-chromium and uranium-iron eutectic alloys at room temperature. The resulting values were intended for use in design calculations until more accurate data at other temperatures was obtained.
Date: April 14, 1953
Creator: McKee, John M., Jr.
Partner: UNT Libraries Government Documents Department

Spreading of Sn-Ag solders on FeNi alloys

Description: The spreading of Sn-3Ag-xBi solders on Fe-42Ni has been studied using a drop transfer setup. Initial spreading velocities as fast as {approx}0.5 m/s have been recorded. The results are consistent with a liquid front moving on a metastable, flat, unreacted substrate and can be described by using a modified molecular-kinetic model for which the rate controlling step is the movement of one atom from the liquid to the surface of the solid substrate. Although the phase diagram predicts the formation of two Fe-Sn intermetallics at the solder/substrate interface in samples heated at temperatures lower than 513 C, after spreading at 250 C only a thin FeSn reaction layer could be observed. Two interfacial layers (FeSn and FeSn2) were found after spreading at 450 C.
Date: February 28, 2003
Creator: Saiz, Eduardo; Hwang, C-W.; Suganuma, Katsuaki & Tomsia, Antoni P.
Partner: UNT Libraries Government Documents Department

Operating Manual for the PSE&G Hydrogen Reservoir Containing Iron Titanium Hydride

Description: Report issued by the Brookhaven National Laboratory discussing the operation of a hydrogen reservoir. As stated in the introduction, "information is provided on how the reservoir functions and how it can be safely operated. The equipment is described and basic operating procedures are given along with precautionary measures" (p. 1). This report includes tables, illustrations, and photographs.
Date: February 1974
Creator: Strickland, G. & Reilly, J. J.
Partner: UNT Libraries Government Documents Department

Development of filler metals for welding of iron aluminide alloys. Final report

Description: Attempts were made to develop a coating formulation for shielded metal arc (SMA) welding electrodes for iron aluminide alloys. Core wires of various compositions were produced by aspiration casting at ORNL and coating formulation development was conducted by Devasco, Inc. It was found that, except for weld deposit compositions containing less than 10 weight % aluminum, all weld deposits exhibited extensive cold cracking and/or porosity. It was concluded that current coating formulation technology limits successful iron aluminide deposits to less than 10 weight % aluminum.
Date: June 29, 1995
Creator: Goodwin, G. M. & Scott, J. L.
Partner: UNT Libraries Government Documents Department

Analytical prediction of the location of ductility dip cracking in the trans-varestraint test

Description: Some NiCrFe weld metals exhibit decreased ductility over a temperature range known as the {open_quotes}ductility dip{close_quotes} temperature (DDT) range. Ductility dip cracking (DDT) is a phenomenon which occurs in a zone bounded by the DDT range on its sides and a threshold plastic strain on its bottom as shown in figure 1. Figure 1 illustrates how ductility varies as weld metal cools from the solidus temperature for materials with and without a ductility dip. The purpose of this work is to demonstrate the ability to predict the location of the DDC in a Trans-Varestraint Test (TVT) for a specimen machined from a weld deposited EN52 plate. The DDC predictions require a combination of Trans-Varestraint testing and finite element analysis. The test provides the threshold value of externally applied nominal strain below which DDC does not occur. The analysis provides the corresponding threshold local or peak strain. The threshold local plastic strain level and the DDT range are used to predict the location of the DDC. The ultimate purpose of this work is to evaluate susceptibility of highly constrained, component welds to DDC. Test results for Trans-Varestraint Testing for a weld deposited EN52 plate are reported in reference. The ability to predict the location of the DDC in the Trans-Varestraint Test using the techniques reported herein is demonstrated by showing good comparison between the analytical results and the test data.
Date: May 1, 1997
Creator: Singh, I.; Kroenke, W. & Cola, M.
Partner: UNT Libraries Government Documents Department

Bonding of WC with an iron aluminide (FeAl) intermetallic

Description: FeAl, which has high oxidation and sulfidation resistance, was shown to be thermodynamically compatible with WC. Calculations indicate that soly. of WC in liq. Fe-40at.%Al at 1450 C is about 2 at.%. Since liquid FeAl wets WC very well, the WC/FeAl system lends itself to liquid-phase sintering, resulting in close to theoretical densities. Almost fully dense cermets with 20.6 wt% FeAl binder were produced. With one-step infiltration, 98% dense cermets with only 7 wt% FeAl binder were fabricated. RT bend strengths and fracture toughness for WC-20.6 wt% FeAl reached 1680 MPa and 22 MPa{center_dot}m{sup 1/2}. Ductile binder fracture was observed on the fracture surfaces. Pores containing oxide inclusions were found, suggesting that improvements in processing are likely to further improve the mechanical properties. Insufficient process control may explain why WC/FeAlNi cermets did not show improved mechanical properties, although Ni strengthens FeAl. For WC bonded with FeAl, mechanical properties were measured at RT and 800 C. Bend strengths at 800 C in air increased with WC volume fraction, and fracture toughness were higher than at RT.
Date: August 1, 1996
Creator: Schneibel, J. H. & Subramanian, R.
Partner: UNT Libraries Government Documents Department

Metal filter materials in combustion environments

Description: Hot gas filtration in pressurized fluidized bed combustion (PFBC) systems has been proven below 750 C (1400 F). Advanced PFBC designs, focused on operational and efficiency improvements, will require filtration at higher temperatures. E.g., in first-generation advanced PFBCs, the filters will have to perform at 870 C (1600 F), while second-generation units, with both carbonizers for fuel-gas production and fluidized-bed combustors, will eventually require filters to operate up to 930 and 870 C (1700 and 1600 F). Results from the final test campaign at the Tidd PFBC Demonstration Project showed that at these higher temperatures, ceramic filter reliability may be problematical, so it will be of interest to re-examine the possibility of using advanced metal hot-gas filters for these advanced PFBC applications in view of the exceptional corrosion resistance of Fe aluminides in high-temperature sulfur-bearing atmospheres. For the second-generation PFBCs, performance criteria for the carbonizer filters are essentially the same as those for integrated gasification combined cycle systems (reducing environments). For the combustor, issues are similar to those of advanced first-generation units (oxidizing) except that the fuel (byproduct char from carbonizer) should be somewhat clearer and filter performance requirements less demanding than for PFBC systems such as the Tidd plant. For the carbonizer system, the nearer term (market entry) goals are to develop filter materials that will perform at 650-760 C (1200-1400 F), with an increase to 800-930 C (1500-1700 F) for improved cycle efficiency.
Date: September 1, 1996
Creator: Judkins, R.R.; Tortorelli, P.F. & Wright, I.G.
Partner: UNT Libraries Government Documents Department

Reaction synthesis of intermetallics

Description: Exothermicity associated with the synthesis of aluminides was utilized to obtain nickel, iron, and cobalt aluminides. Combustion synthesis, extrusion, and hot pressing were utilized to obtain intermetallics and their composites. Extrusion conditions, reduction ratios, and hot-pressing conditions of the intermetallics and their composites are discussed.
Date: December 1994
Creator: Deevi, S. C. & Sikka, V. K.
Partner: UNT Libraries Government Documents Department

The mechanical properties of FeAl

Description: Only in the last few years has progress been made in obtaining reproducible mechanical properties data for FeAl. Two sets of observations are the foundation of this progress. The first is that the large vacancy concentrations that exist in FeAl at high temperature are easily retained at low temperature and that these strongly affect the low-temperature mechanical properties. The second is that RT ductility is adversely affected by water vapor. Purpose of this paper is not to present a comprehensive overview of the mechanical properties of FeAl but rather to highlight our understanding of key phenomena and to show how an understanding of the factors which control the yield strength and fracture behavior has followed the discovery of the above two effects. 87 refs, 9 figs.
Date: December 31, 1996
Creator: Baker, I. & George, E.P.
Partner: UNT Libraries Government Documents Department

Crystal structure and phase stability in Fe{sub 1{minus}x}Co{sub x} from AB initio theory

Description: For alloys between Fe and Co, their magnetic properties determine their structure. From the occupation of d states, a phase diagram is expected which depend largely on the spin polarization. A method more elaborate than canonical band models is used to calculate the spin moment and crystal structure energies. This method was the multisublattice generalization of the coherent potential approximation in conjunction with the Linear-Muffin-Tin-Orbital method in the atomic sphere approximation. To treat itinerant magnetism, the Vosko-Wilk-Nusair parameterization was used for the local spin density approximation. The fcc, bcc, and hcp phases were studied as completely random alloys, while the {alpha}{prime} phase for off-stoichiometries were considered as partially ordered. Results are compared with experiment and canonical band model.
Date: June 1, 1996
Creator: Soederlind, P.; Abrikosov, I.A.; James, P.; Johansson, B. & Eriksson, O.
Partner: UNT Libraries Government Documents Department

Effects of symmetry on circular and linear magnetic dichroism in angle-resolved photoemission spectra of Gd/Y (0001) and Fe-Ni//Cu (001)

Description: We have observed circular and linear magnetic dichroism in angle- resolved photoemission spectra of 50-monolayer Gd film grown on Y(0001) and 6-monolayer Fe-Ni alloy films grown on Cu(001). The 4f level of Gd and the Fe 3p level of the Fe-Ni alloy were measured. A different geometry was used for the magnetic circular dichroism than was used to measure the magnetic linear dichroism. The geometries were chosen so that the shape of the magnetic circular dichroism is predicted to be equal to the shape of the magnetic linear dichroism for four-fold symmetric Fe-Ni/Cu(001) but not for three-fold symmetric Gd/Y(0001). Experimental results are presented. In this paper we examine the effect of symmetry (experimental geometry and sample geometry) on magnetic linear and circular dichroism in angle- resolved photoemission. In particular we chose separate geometries for measuring magnetic circular and magnetic linear dichroism. The geometries were chosen such that samples with four-fold symmetry about the sample normal may have magnetic circular and magnetic linear dichroism of the same shape. But samples with three-fold symmetry should not exhibit circular and magnetic linear dichroism of the same shape. The samples studied are three-fold symmetric Gd films grown on Y(0001) and four-fold symmetric Fe-Ni alloy grown on Cu(001). After presenting the methods of the experiment, we briefly review parts of a model of magnetic dichroism developed by Venus and coworkers and our specialization and extension of it, particularly for FeNi/Cu(001). We then show the results of our measurements.
Date: March 26, 1997
Creator: Goodman, K.W.; Tobin, J.G.; Schumann, F.O.; Willis, R.F.; Gammon, J.W.; Pappas, D.P. et al.
Partner: UNT Libraries Government Documents Department

Methods for preparation of extremely fine superalloy powders and fabrication to superalloy parts. Final report, October 1, 1995--February 15, 1998

Description: The use of reducing agents such as sodium borohydride have been used in a wide variety of chemical reactions from organic compounds synthesis to metal production. In order to reduce metal ions into the metallic state, the solution electrochemical potential must be sufficiently low to allow the metal to accept electrons from the reducing agent. One information source that gives important information regarding the conditions necessary for spontaneous aqueous nickel metal reduction is the electroless nickel plating literature. Although nickel is not the only desired metal, it provides an important starting point in metal reduction, and it is useful because of its resistance to corrosion. The electroless nickel plating literature indicates that sodium hypophosphite, sodium borohydride, and hydrazine are all used as reductants. Sodium hypophosphite is usually used at 30--95 C in a bath containing dissolved nickel sulfate and other additives such as oxalic acid and ammonium chloride. Sodium borohydride is usually used with sodium hydroxide in a similar temperature range. Hydrazine is also used with sodium hydroxide in a similar temperature range. However, in order to make the transition from electroless nickel deposition to spontaneous metal powder production requires different conditions. In this research program, a number of different conditions were examined to determine optimum conditions for the production of metal and metal alloy powders in aqueous solutions.
Date: July 1, 1998
Creator: Natesh, R.
Partner: UNT Libraries Government Documents Department

Enhanced spin-valve giant magneto-resistance in non-exchange biased sandwich films

Description: A large giant magnetoresistance (GMR) value of 7.5% has been measured in simple NiFeCo(1)/Cu/NiFeCo(2) sandwich films grown on a 30 {angstrom} Cr seed layer. This spin-valve GMR effect is consistent with the differential switching of the two NiFeCo layers due to an enhanced coercivity of the NiFeCo(1) layer grown on the Cr seed layer. A change in growth texture of the NiFeCo(1) layer from fcc (111) to bcc (110) crystallographic orientation leads to an increase in magnetic anisotropy and an enhancement in coercivity. The GMR value increases to 8.7% when a thin CoFe interfacial enhancing layer is incorporated. Further enhancement in GMR values up to 14% is seen in the sandwich films by nano-oxide layer formation. The specular reflection at oxide/magnetic layer interface further extends the mean free path of spin-polarized electrons.
Date: February 17, 2000
Creator: Mao, M; Cerjan, C; Law, B; Grabner, F; Miloslavsky, L & Chien, C
Partner: UNT Libraries Government Documents Department

Refracted x-ray fluorescence (RXF) applied to the study of thermally grown oxide scales on Fe-Cr-Ni-(RE) alloys.

Description: Refracted X-Ray Fluorescence (RXF) is applied to the study of the thermally grown scales on Fe25Cr20Ni(RE) alloys. The evolution of chromia scales is investigated for alloys containing reactive elements (RE) Y and Zr as well as the corresponding RE-free alloy. For these alloys, scale compositions, scale thicknesses and growth rates are measured and information about concentration depth profiles is obtained.
Date: June 3, 1998
Creator: Koshelev, I.
Partner: UNT Libraries Government Documents Department

The correlation between swelling and radiation-induced segregation in iron-chromium-nickel alloys.

Description: The magnitudes of both void swelling and radiation-induced segregation (RIS) in iron-chromium-nickel alloys are dependent on bulk alloy composition. Because the diffusivity of nickel via the vacancy flux is slow relative to chromium, nickel enriches and chromium depletes at void surfaces during irradiation. This local composition change reduces the subsequent vacancy flux to the void, thereby reducing void swelling. In this work, the resistance to swelling from major element segregation is estimated using diffusivities derived from grain boundary segregation measurements in irradiated iron-chromium-nickel alloys. The resistance to void swelling in iron- and nickel-base alloys correlates with the segregation and both are functions of bulk alloy composition. Alloys that display the greatest amount of nickel enrichment and chromium depletion are found to be most resistant to void swelling, as predicted. Additionally, swelling is shown to be greater in alloys in which the RIS profiles are slow to develop.
Date: March 5, 1998
Creator: Allen, T. R.; Busby, J. T.; Kenik, E. A. & Was, G. S.
Partner: UNT Libraries Government Documents Department