HIGH-TEMPERATURE DEFORMATION OF ZRO2-AL2O3 SIC WHISKER COMPOSITES FABRICATED BY 2 TECHNIQUES/

ZrO2-Al2O3/SiC whisker-reinforced composites, with whisker volume frac tions of 0%-28%, fabricated both by powder and precursor processing, h ave been deformed at temperatures of 1300-1500 degrees C under constan t compression rates of 1.7 x 10(-5) to 6.8 x 10(-5) s(-1). Above 1400 degrees C, a stress at which the work-hardening rate became zero could be measured and correlated with whisker content. On the contrary, at 1300 degrees C all samples broke within the elastic regime. At 1350 de grees C, increased whisker content appeared to inhibit fracture, so pl astic behavior was obtained for samples containing 28% SIG. In the ran ge of temperatures and compression rates, noted above, stress exponent s were determined and tentatively correlated with microstructural feat ures and their evolution during plastic deformation.