Senior specialist engineer, Boeing Defense and Space Group, Seattle, WA
Boeing Pennell Professor in Structure Mechanics, University of Washington, Seattle, WA
Pages: 10 Published: Jan 1994
A bar impact test procedure was used to study spallation of Al2O3 bars and dynamic fracture of Al2O3 and SiCw/Al2O3 bars. Fractography analysis of the spalled surface showed extensive intergranular fracture (90 to 95% area). Dynamic fracture studies of precracked Al2O3 and SiCw/Al2O3 bars showed that the dynamic initiation fracture toughness, KId, and the crack branching stress intensity factor, KIb, remained constant with increased impact velocity, that is, impact stress. Despite the increase in static fracture toughness, KIc with the addition of SiC whiskers in A12O3 matrix, KIds and KIbs of Al2O3 and SiCw/Al2O3 were about the same, suggesting that the SiC whiskers are not effective in dynamic fracture.
dynamic fracture, impact damage, spallation, alumina, silicon-carbide whiskers, ceramic composite
Paper ID: STP13739S