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Strength of Crack Healed-Specimen and Elastic Wave Characteristics of Al2O3/SiC Composite Ceramics

알루미나 탄화규소 복합세라믹스 균열치유재의 강도와 탄성파 특성

  • 김해숙 (부경대학교 대학원) ;
  • 김미경 (경도대학 대학원) ;
  • 김진욱 (한국기계연구원 원자력공인사업단) ;
  • 안석환 (부경대학교 기계공학부) ;
  • 남기우 (부경대학교 신소재공학부)
  • Published : 2007.04.01

Abstract

[ $Al_2O_3/SiC$ ]composite ceramics were sintered to evaluate the bending strength and elastic wave characteristics. The three-point bending test was carried out under room temperature. The elastic wave was detected by fracture wave detector. The crack healing behavior was investigated from 1373 K to 1723 K. The bending strength of $Al_2O_3/SiC$ composite by nanocomposite is higher than that of $Al_2O_3$ monolithic. Crack-healing behavior depended on an amount of additive powder $Y_2O_3$. In $Al_2O_3/SiC$ composite ceramics with 3 wt. % $Y_2O_3$ for additive powder, the bending strength at 1573 K is about 100% increase than that of the smooth specimens. From the result of wavelet analysis of elastic wave signal, the smooth specimen and heat treated specimen of $Al_2O_3$ monolithic and $Al_2O_3/SiC$ composite ceramics showed characteristics of frequency about 58 kHz. The strength of $Al_2O_3/SiC$ composite ceramics was a little higher than those of $Al_2O_3$ monolithic. The dominant frequencies were high with increasing of $Y_2O_3$ for additive powder. The dominant frequencies had direct connection with the bending strength.

Keywords

$Al_2O_3/SiC$ Composite Ceramics;Additive Powder $Y_2O_3$;Bending Strength;Crack Healing;Dominant Frequency;Elastic Wave;Wavelet Analysis

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