STACKING-FAULTS IN SIC PARTICLES AND THEIR EFFECT ON THE FRACTURE-BEHAVIOR OF A 15-VOL-PCT SIC 6061-AL MATRIX COMPOSITE/

Mechanical tests and microstructural examinations performed on a SiC-p article-reinforced 6061-Al matrix composite indicate that particle cra cking during mechanical testing significantly affects the failure mech anisms of the composite. Microcracks were observed to nucleate and pro pagate on stacking faults and interfaces between the 4H (or 3C) and 6H hexagonal phases within the SiC particle reinforcements. These planar defects were the predominant defects seen in the SiC particles. Parti al dislocations, having a 1/3 [<10(1)over bar 0] Burgers vector, were also observed bounding the stacking faults in the reinforcement phase.