Accession Number : AD0885295

Title :   STABILITY CHARACTERIZATION OF REFRACTORY MATERIALS UNDER HIGH VELOCITY ATMOSPHERIC FLIGHT CONDITIONS. PART V. VOLUME I. ADDITIONAL STUDIES.

Descriptive Note : Technical rept., Nov 69-Dec 70,

Corporate Author : MANLABS INC CAMBRIDGE MA

Personal Author(s) : KAUFMAN, Larry ; Nesor, Harvey

Report Date : APR 1971

Pagination or Media Count : 214

Abstract : The oxidation of refractory borides, graphites and JT composites, hypereutectic carbide-graphite composites, refractory metals, coated refractory metals over the extensive spectrum of environmental conditions encountered during reentry or high velocity atmospheric flight, as well as those employed in furnace tests was studied. Male and Female configurations of simple nosetip and leading edge structures composed of boride components threaded into coated tantalum holders have been designed and tested successfully for 1800 seconds with no cracking at Mach 3.2 at 520-548 BTU/sq ft sec, 8550 BTU/lb and 0.063 atm. Total oxidation was 29-36 mils at temperatures near 4700F for these tests, or 30-60 times less than comparable recessions for tungsten or graphite. In addition a six cycle exposure of a male nosetip was successfully performed including a 100 BTU/sq ft sec exposure, a 460 BTU/sq ft sec segment followed by four 200 BTU/sq ft sec cycles with a total oxidation depth of 10 mils. No other materials system known currently can match this performance in heat flux, temperature and oxidation resistance and fabricability. (Author)

Descriptors :   *REFRACTORY MATERIALS, *OXIDATION, *ATMOSPHERE ENTRY, REFRACTORY COATINGS, HYPERSONIC FLOW, BORIDES, GRAPHITE, COMPOSITE MATERIALS, CARBIDES, TUNGSTEN ALLOYS, ZIRCONIUM ALLOYS, MICROSTRUCTURE, SOLID SOLUTIONS, REFRACTORY METAL ALLOYS, COPPER ALLOYS, SILICON CARBIDES, ZIRCONIUM OXIDES, NITRIDES, TANTALUM ALLOYS, HEAT TRANSFER, HEAT FLUX, SURFACES.

Subject Categories : Ceramics, Refractories and Glass

Distribution Statement : APPROVED FOR PUBLIC RELEASE