Mechanical Properties of the Pressureless Sintered $Al_2O_3-SiC$ Composite(1) : Dispersion Effects of SiC Powder

상압소결 $Al_2O_3-SiC$계 소결체의 기계적 성질 (I) : SiC분말의 분산효과

  • 이홍림 (연세대학교 공과대학 요업공학과) ;
  • 김경수 (연세대학교 공과대학 요업공학과) ;
  • 이형복 (명지대학교 공과대학 무기재료공학과)
  • Published : 1988.03.01


In order to investigate the effect of second phase on $Al_2O_3$ matrix, SiC particles were dispersed in $Al_2O_3$ matrix as a second phase over the content range of 5 vol.% to 20 vol.%. To this mixture, $Y_2O_3$ or $TiO_2$ powders were added as a sintering additive before isostatically pressing and pressurelessly sintering at 180$0^{\circ}C$ for 90 min in $N_2$ atmosphere. With increasing SiC content, relative densities of composites were decreased but mechanical properties of composites were improvjed. In the case of adding $Y_2O_3$ as a sintering additive, maximum values of flexural strength, hardness and fracture toughness were 525 MPa, 17.1 GPa, 4.1 MPa.m1/2 respectively. In the case of adding X$TiO_2$ as a sintering additive, maximum values of flexural strength, hardness were 285 MPa, 12.1 GPa respectively. Improved mechanical properties were found to be the results of grain growth control of $Al_2O_3$ matrix and crack deflection by the second phase SiC particles.



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