NASA Scientific and Technical Aerospace Reports
NASA Scientific and Technical Aerospace Reports
NASA Scientific and Technical Aerospace Reports
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20040120859 Duquesne Univ., Pittsburgh, PA, USA<br />
Substituted Iron Oxides<br />
Sorescu, M.; Mar. 2004; 36 pp.; In English<br />
Report No.(s): DE2004-822034; No Copyright; Avail: Department of Energy Information Bridge<br />
Structural <strong>and</strong> morphological characteristics of (1-x)(alpha)-Fe(sub 2)O(sub 3)-xSnO(sub 2) (x= 0.0-1.0) nanoparticles<br />
obtained under hydrothermal conditions have been investigated by X-ray diffraction (XRD), transmission Moessbauer<br />
spectroscopy, scanning (SEM) <strong>and</strong> transmission electron microscopy (TEM) as well as energy dispersive X-ray analysis<br />
(EDX).<br />
NTIS<br />
Iron Oxides; Intermetallics<br />
20040120877 <strong>NASA</strong> Langley Research Center, Hampton, VA, USA<br />
An Ultrasonic Study on Anelasticity in Metals<br />
Namkug, M.; Fulton, J. P.; Nath, S.; Wincheski, B.; [1990]; 8 pp.; In English; No Copyright; Avail: CASI; A02, Hardcopy<br />
A new ultrasonic approach for monitoring the anelastic behavior of metals <strong>and</strong> alloys was presented. The approach poses<br />
some problems related to separating the temperature dependence of the anelastic phenomena from the natural wave velocity<br />
s susceptibility to temperature changes. However, these effects can be distinguished <strong>and</strong> separated without much difficulty. Due<br />
to its high sensitivity to microstructural changes, the new technique will be quite valuable when used in conjunction with strain<br />
gauges for studying anelastic behavior. The two techniques should complement each other quite well. In the future, tests using<br />
both the P2L2 <strong>and</strong> strain gauges to more thoroughly monitor the samples will be conducted. Further work will be done to fully<br />
characterize the temperature sensitivity of the velocity <strong>and</strong> provide a more solid foundation for separating its effects.<br />
Author<br />
Anelasticity; Ultrasonics; Metals; Alloys; Magnetoacoustics<br />
20040120942 Clevel<strong>and</strong> State Univ., Clevel<strong>and</strong>, OH, USA<br />
A Comparison between Growth Morphology of ‘Eutectic’ Cells/Dendrites <strong>and</strong> Single-Phase Cells/Dendrites<br />
Tewari, S. N.; Raj, S. V.; Locci, I. E.; Metallurgical <strong>and</strong> Materials Transactions A; September 11, 2003; Volume 35A,<br />
pp. 1632-1635; In English<br />
Contract(s)/Grant(s): 708-04-05; No Copyright; Avail: CASI; A01, Hardcopy<br />
Directionally solidified (DS) intermetallic <strong>and</strong> ceramic-based eutectic alloys with an in-situ composite microstructure<br />
containing finely distributed, long aspect ratio, fiber, or plate reinforcements are being seriously examined for several<br />
advanced aero-propulsion applications. In designing these alloys, additional solutes need to be added to the base eutectic<br />
composition in order to improve heir high-temperature strength, <strong>and</strong> provide for adequate toughness <strong>and</strong> resistance to<br />
environmental degradation. Solute addition, however, promotes instability at the planar liquid-solid interface resulting in the<br />
formation of two-phase eutectic ‘colonies.’ Because morphology of eutectic colonies is very similar to the single-phase cells<br />
<strong>and</strong> dendrites, the stability analysis of Mullins <strong>and</strong> Sekerka has been extended to describe their formation. Onset of their<br />
formation shows a good agreement with this approach; however, unlike the single-phase cells <strong>and</strong> dendrites, there is limited<br />
examination of their growth speed dependence of spacing, morphology, <strong>and</strong> spatial distribution. The purpose of this study is<br />
to compare the growth speed dependence of the morphology, spacing, <strong>and</strong> spatial distribution of eutectic cells <strong>and</strong> dendrites<br />
with that for the single-phase cells <strong>and</strong> dendrites.<br />
Author<br />
Eutectic Alloys; Dendritic Crystals; Crystal Growth; Liquid-Solid Interfaces; Spatial Distribution<br />
20040120955 <strong>NASA</strong> Langley Research Center, Hampton, VA, USA, Army Research Lab., Hampton, VA, USA<br />
A Comparison of Weld-Repaired <strong>and</strong> Base Metal for Inconel 718 <strong>and</strong> CRES 321 at Cryogenic <strong>and</strong> Room Temperatures<br />
Newman, John A.; Smith, Stephen W.; Willard, Scott A.; Piascik, Robert S.; August 2004; 27 pp.; In English<br />
Contract(s)/Grant(s): WU 23-104-08-41<br />
Report No.(s): <strong>NASA</strong>/TM-2004-213253; ARL-TR-3266; L-19043; No Copyright; Avail: CASI; A03, Hardcopy<br />
Fatigue crack growth tests were conducted to characterize the performance of Inconel 718 <strong>and</strong> CRES 321 welds, weld<br />
heat-affect-zone <strong>and</strong> parent metal at room temperature laboratory air <strong>and</strong> liquid nitrogen (-196oC) environments. The results<br />
of this study were required to predict the damage tolerance behavior of proposed orbiter main engine hydrogen fuel liner weld<br />
repairs. Experimental results show that the room <strong>and</strong> cryogenic temperature fatigue crack growth characteristics of both alloys<br />
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