Abstract
Cavitation of superplastic metal matrix (6061Al alloy) composite reinforced by 20% volume fraction of Si3N4, particulate and Si3N4, whisker has been investigated. A constant stress tention test was carried out at temperature of 818K and stress of 8MPa for the composite containing Si3N4, particulate, and at 833K, 10MPa for the composite containing Si3N4, whisker. Volume of cavity in the Si3N4p/6061Al composite was larger than that in the Si3N4w/6061Al composite at a range of strain up to 1.5. Both composites already included the volume of cavity of 0.6-0.8% at a strain of 0.2. Cavity volume fraction exponentially increased with increasing strain. Most cavities of both composites were nucleated at the interface of matrix and reinforcements. Cavities in the Si3N4p/6061Al composite were almost granular and those in the Si3N4w/6061Al composite were either granular or flat.
