Study on the R-curve Behaviour in <TEX>$Al_2O_3-ZrO_2-SiC$</TEX> Whisker Comosite

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J. Korean Ceram. Soc. > Volume 30(9); 1993 > Article

Journal of the Korean Ceramic Society 1993;30(9): 731.

$Al_2O_3-ZrO_2-SiC$ Whisker 복합재료에서의 R-curve 거동에 관한 연구

김현하, 박현¹, 최성철

한양대학교 무기재료공학과
¹삼척산업대학교 재료공학과

Study on the R-curve Behaviour in $Al_2O_3-ZrO_2-SiC$ Whisker Comosite

ABSTRACT

R-curve measurements were performed on Al2O3(matrix)-ZrO2-SiC whisker composite and Al2O3-ZrO2, Al2O3-SiC whisker composites in the favor of comparing the effect of ZrO2 and SiC whisker, as a second phase, to Al2O3 matrix. Al2O3-SiC whisker and Al2O3-ZrO2-SiC whisker were fabricated by hot pressing at 1$700^{circ}C$, 15MPa and Al2O3-ZrO2 by pressureless sintering at 1$600^{circ}C$. A controlled flaw/strength technique was utilized to determine fracture resistance as a function of crack extension and R-curve behaviour was determined from the relationship which is KR=K0(Δa)m. R-curveresults were KR=6.173$times$Δa0.031 for Al2O3-ZrO2, KR=18.796$times$Δa0.172 for Al2O3-SiC whisker and KR=11.96$times$Δa0.110 for Al2O3-ZrO2-SiC whisker composite. From the analysis of R-curve and expeirmental data above three composites, it is found that R-curve behaviour of Al2O3-ZrO2-SiC whisker composite was dominated initially by the strengthening effect of ZrO2 and after, some extended crack were influenced by the effect of SiC whisker. Analysis of SEM and X-ray data revealed that whisker bridging in the crack wake and whisker pull-out mechanisms were the main mechanism for the R-curve behaviour.