Accession Number : AD0881239

Title :   Investigation of the Properties of Carbon-Carbon Composites and their Relationship to Nondestructive Test Measurements.

Descriptive Note : Annual rept. 1 Jun 69-1 Jun 70,

Corporate Author : MCDONNELL DOUGLAS ASTRONAUTICS CO-WEST SANTA MONICA CA

Personal Author(s) : Evangelides, John S. ; Meyer, Robert A.

Report Date : JAN 1971

Pagination or Media Count : 310

Abstract : Material variations and discrete discontinuities can be encountered in carbon-arboncomposites. This requires that those variations that affect the quality andperformance of the composite be identified and characterized. The approach tothis problem was to characterize the precursor materials and apply nondestructiveanalysis and mechanical testing to the carbon-carbon materials after variousprocessing steps to assist in identifying and characterizing these propertiesthat affect the performance of uni-and multidirectional carbon-carbon composites.By modifying the ultrasonic attenuation method with the use of a collimatedreceiver, the limit of defect detectability of this technique was increased.X-ray radiography was applied to the composite systems and the informationcontained in the X-ray radiographs was related to the defects present in thecomposite. Neutron radiography was evaluated as a method examining thecomposites and the results were not as good as with X-ray radiography. It wasconcluded that monitoring material uniformities and detecting discretediscontinuities in unidirectional multidirectional carbon-carbon composites onan in-process basis can be successfully accomplished. (Author, modified-PL)

Descriptors :   *CARBON), (*COMPOSITE MATERIALS, (*CARBON FIBERS, COMPOSITE MATERIALS), (*NONDESTRUCTIVE TESTING, COMPOSITE MATERIALS), CRYSTAL DEFECTS, THERMAL STABILITY, THERMOGRAVIMETRIC ANALYSIS, X RAY PHOTOGRAPHY, ULTRASONIC PROPERTIES, MECHANICAL PROPERTIES, PYROLYSIS.

Subject Categories : Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE