Scientific and Technical Aerospace Reports Volume 38 July 28, 2000

pathways to precursors that produce high purity, two phase In2O3-SnO2. The precursors were formed by complexation of tin with
any oxide ligands to give the ammonium salt (NH4). Thermal studies of these precursors were carried out by thermal gravimetry
(TG) and differential scanning calorimetry (DSC). Further studies by Fourier transform infrared spectroscopy (FTIR) and nuclear
magnetic resonance spectroscopy (NMR) were also conducted.
Author
Thermodynamic Properties; Combustion Chemistry; Combustion Products; Ito (Semiconductors); Nitrogen Oxides; Metal
Oxides
20000065664 Los Alamos National Lab., NM USA
Quantification of damage evolution for a micromechanical model of ductile fracture in spallation of tantalum
Zurek, A. K.; Thissell, W. R.; Tonks, D. L.; Hixon, R.; Addessio, F.; Dec. 31, 1997; 10p; In English; Mechanical and physical
behavior of materials under dynamic loading (EURO/DYMAT)
Report No.(s): DE97-005014; LA-UR-97-791; No Copyright; Avail: Department of Energy Information Bridge
The authors present quantification of micromechanical features such as voids that comprise the ductile fracture obtained
under uniaxial strain condition in a spall test of commercial purity tantalum. Two evolutionary parameters of ductile fracture void
formation are quantified: (i) the void volume fraction (porosity) and its distribution with respect to the distance from the main
spall fracture plane, and (ii) void diameter distribution.
NTIS
Damage; Ductility; Fracture Mechanics; Quantitative Analysis
20000067654 Florida Agricultural and Mechanical Univ., Tallahassee, FL USA
Micromechanical Characterization and Texture Analysis of Direct Cast Titanium Alloys Strips Final Report
Jun. 20, 2000; 73p; In English; Original contains color illustrations
Contract(s)/Grant(s): NAG1-1866; No Copyright; Avail: CASI; A04, Hardcopy; A01, Microfiche
This research was conducted to determine a post-processing technique to optimize mechanical and material properties of a
number of Titanium based alloys and aluminides processed via Melt Overflow Solidification Technique (MORST). This technique
was developed by NASA for the development of thin sheet titanium and titanium aluminides used in high temperature
applications. The materials investigated in this study included conventional titanium alloy strips and foils, Ti-1100, Ti-24Al-11Nb
(Alpha-2), and Ti-48Al-2Ta (Gamma). The methodology used included micro-characterization, heat-treatment, mechanical processing
and mechanical testing. Characterization techniques included optical, electron microscopy, and x-ray texture analysis. The
processing included heat-treatment and mechanical deformation through cold rolling. The initial as-cast materials were evaluated
for their microstructure and mechanical properties. Different heat-treatment and rolling steps were chosen to process these materials.
The properties were evaluated further and a processing relationship was established in order to obtain an optimum processing
condition. The results showed that the as-cast material exhibited a Widmanstatten (fine grain) microstructure that developed into
a microstructure with larger grains through processing steps. The texture intensity showed little change for all processing performed
in this investigation.
Derived from text
Characterization; Mechanical Properties; Micromechanics; Textures; Titanium Alloys; Titanium Aluminides; Metal Strips; Cast
Alloys
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NONMETALLIC MATERIALS
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20000062452 Saclay Research Centre, Inst. National des Sciences et Techniques Nucleaires, Gif-sur-Yvette, France
Conformation and arrangement of polyelectrolytes in semi-diluted solution: A study by small angle neutrons scattering
Spiteri, M. N.; Mar. 25, 1997; 205p; In French; In English
Report No.(s): DE98-732052; FRCEA-TH-608; No Copyright; Avail: Department of Energy Information Bridge
Polyelectrolytes have particular physical and chemical properties and can thus be used for instance for petroleum production.
Some of their microscopic properties have been studied in this work. With the particular zero average contrast technique, the small
angle neutron scattering allows to directly know the form factors in semi-diluted solutions of polyelectrolytes where the chains
are mixed. Another measure leads to the crystal structure. The electrostatic screen effects when salt is added in aqueous solutions