Final rept. 1985-1987,
MARYLAND UNIV COLLEGE PARK METALLURGICAL MATERIALS LAB
Pagination or Media Count:
In all cases of discontinuous silicon carbidealuminum 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 SiCAL 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.
- Laminates and Composite Materials