Accession Number : ADA189258

Title :   Composites Strengthening.

Descriptive Note : Final rept. 1985-1987,

Corporate Author : MARYLAND UNIV COLLEGE PARK METALLURGICAL MATERIALS LAB

Personal Author(s) : Arsenault, Richard J

PDF Url : ADA189258

Report Date : Nov 1987

Pagination or Media Count : 172

Abstract : In all cases of discontinuous silicon carbide/aluminum metal matrix it was previously shown that classical composite strengthening mechanisms could not be used to explain the data. A high dislocation density model was proposed to account for the strengthening, but other factors such as residual stress and texture could contribute. These were investigated and it was shown that texture had no effect and residual stress reduced the tensile yield stress. The fracture process is matrix controlled up to SiC particle sizes of 20 micrometers and above where fracture of SiC begins to dominate. The matrix is influenced by residual hydrostatic tension and high density of dislocations generated at SiC/AL interfaces. Crack initiation fracture toughness does not depend on SiC particle size. Crack growth fracture toughness increases as the size of the SiC particles increases.

Descriptors :   *WHISKER COMPOSITES, *METAL MATRIX COMPOSITES, COMPOSITE MATERIALS, DENSITY, FRACTURE(MECHANICS), HYDROSTATICS, PARTICLE SIZE, RESIDUAL STRESS, STRENGTH(MECHANICS), TENSILE STRESS, TOUGHNESS, SILICON CARBIDES, ALUMINUM ALLOYS, CRACK PROPAGATION, INTERFACES

Subject Categories : Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE