Accession Number : ADA183882

Title :   Investigation of Rapidly-Solidified Dispersion Strengthened Titanium Alloys.

Descriptive Note : Annual rept. Sep 85-Aug 86,

Corporate Author : UNITED TECHNOLOGIES RESEARCH CENTER EAST HARTFORD CT

Personal Author(s) : Snow, David B

PDF Url : ADA183882

Report Date : 01 Jul 1987

Pagination or Media Count : 103

Abstract : Significant potential exists for the improvement of high temperature strength in titanium base alloys by the addition of rare earth elements, followed by rapid solidification and aging. To investigate this potential, the relative effectiveness with which several different rare earth elements form oxide dispersions in splat-quenched Ti-AI solid solutions was examined, using Ti-A-Er as a basis of comparison. The alloying elements of this type which were utilized included yttrium, lanthanum, neodymium, gadolinium, terbium, dysprosium, erbium and lutetium, added individually in amounts of approx. 0.5 at % each. Procedures were developed to prepare rapidly solidified laboratory quantities of these alloys by arc melting and splat quenching in the same apparatus, followed by aging in high purity argon. The dispersions formed in these alloys both before and after aging at 800 C were examined and compared by analytical transmission electron microscopy. While it was not generally possible to completely suppress the precipitation of intercellular oxides by splat quenching to thicknesses of greater than 60 micron, in all cases most of the yttrium or the rare earth component of the alloy was retained in supersaturated solid solution. (Keywords:) Splat quenching , Titanium Martensite, Titanium-aluminum alloys, Yttrium oxide, Neodymium oxide , Rapid solidification.

Descriptors :   *HIGH STRENGTH ALLOYS, ALUMINUM COMPOUNDS, ARC MELTING, ARGON, DISPERSIONS, DYSPROSIUM, ELECTRON MICROSCOPY, ERBIUM, GADOLINIUM, HIGH RATE, HIGH TEMPERATURE, LABORATORIES, LANTHANUM, LUTETIUM, MARTENSITE, NEODYMIUM, OXIDES, PURITY, QUANTITY, QUENCHING, QUICK REACTION, RARE EARTH ELEMENTS, SOLID SOLUTIONS, SOLIDIFICATION, SPRAYS, SUPERSATURATION, TERBIUM, THICKNESS, TITANIUM, TITANIUM COMPOUNDS, TRANSMITTANCE, YTTRIUM, YTTRIUM OXIDES, STRENGTH WEIGHT RATIO, MICROSTRUCTURE, FAILURE, STRESSES

Subject Categories : Properties of Metals and Alloys
      Fabrication Metallurgy

Distribution Statement : APPROVED FOR PUBLIC RELEASE