Accession Number : AD0868270

Title :   Improved Graphite Materials for Re-Entry Vehicles. Volume III.

Descriptive Note : Annual rept. no. 2, 1 Jan-31 Dec 69,

Corporate Author : GENERAL ELECTRIC CO PHILADELPHIA PA RE-ENTRY SYSTEMS DEPT

Personal Author(s) : Stover, Edward R.

Report Date : APR 1970

Pagination or Media Count : 164

Abstract : Processing studies and preliminary material characterization data are described for several types of carbon/carbon composites in which a reinforcement constituent extends in several directions in three dimensions. The principles of 4-directional reinforced nose tip ma-terials are described. The first 7- directional yarn reinfor-cement has been fabricated under this contract. Modifica- tions to a 150 C softening point coal tar pitch were ex-plored, and this pitch was used for the matrix in a 4-D reinforced graphite made from Type 2, PAN precursor, 10,000 filament tow. Although ablation performance and impact resistance (inplate slap) were facorable, the high anisotropy inherent to this fiber system tends to limit mechanical strength. Strength, elastic modulus, and thermal expansion doefficient have been characterized as a function of fiber packing angle in this composite. Limited data on CVD-in-filtrated unidirectional and 4-directional fiber systems has also been obtained. Comparative ablation tests have been performed with a channel flow facility and a miniature high pressure facility, and use of a laser for vaporization screening was explored. Scanning electron microscopy shows that rayon precursor carbon and graphite filaments are oxidized or vaporized preferentially, while PAN-precursor filaments are often etched in relief. (Author-PL)

Descriptors :   (*REENTRY VEHICLES, HEAT SHIELDS), (*GRAPHITE, THERMAL PROPERTIES), ABLATION, COMPOSITE MATERIALS, CARBON FIBERS, PYROLYTIC GRAPHITE, GRAPHITED MATERIALS.

Subject Categories : Laminates and Composite Materials
      Guided Missile Dynam, Config & Cntrl Surfaces
      Guided Missile Reentry Vehicles

Distribution Statement : APPROVED FOR PUBLIC RELEASE