In situ toughened silicon carbide with Al-B-C additions

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Joe J. Cao
  • Warren J. MoberlyChan
  • Lutgard C. De Jonghe
  • Christopher J. Gilbert
  • Robert O. Ritchie

Detail(s)

Original languageEnglish
Pages (from-to)461-469
Journal / PublicationJournal of the American Ceramic Society
Volume79
Issue number2
Online publishedFeb 1996
Publication statusPublished - Feb 1996
Externally publishedYes

Abstract

"In situ toughened" silicon carbides, containing Al, B, and C additives, were prepared by hot pressing. Densification, phase transformations, and microstructural development were described. The microstructures, secondary phases, and grain boundaries were characterized using a range of analytical techniques including TEM, SEM, AES, and XRD. The modulus of rupture was determined from four-point bend tests, while the fracture toughness was derived either from bend tests of beam-shaped samples with a controlled surface flaw, or from standard disk-shaped compact-tension specimens precracked in cyclic fatigue. The R-curve behavior of an in situ toughened SiC was also examined. A steady-state toughness over 9 MPa·m1/2 was recorded for the silicon carbide prepared with minimal additives under optimum processing conditions. This increase in fracture toughness, more than a factor of three compared to that of a commercial SiC, was achieved while maintaining a bend strength of 650 MPa. The mechanical properties were found to be related to a microstructure in which platelike grain development had been promoted and where crack bridging by intact grains was a principal source of toughening. References.

Citation Format(s)

In situ toughened silicon carbide with Al-B-C additions. / Cao, Joe J.; MoberlyChan, Warren J.; De Jonghe, Lutgard C.; Gilbert, Christopher J.; Ritchie, Robert O.

In: Journal of the American Ceramic Society, Vol. 79, No. 2, 02.1996, p. 461-469.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review