Member, American Ceramic Society.
Toughness Properties of a Silicon Carbide with an in Situ Induced Heterogeneous Grain Structure
Article first published online: 8 MAR 2005
Journal of the American Ceramic Society
Volume 77, Issue 10, pages 2518–2522, October 1994
How to Cite
Padture, N. P. and Lawn, B. R. (1994), Toughness Properties of a Silicon Carbide with an in Situ Induced Heterogeneous Grain Structure. Journal of the American Ceramic Society, 77: 2518–2522. doi: 10.1111/j.1151-2916.1994.tb04637.x
G. Grathwohl—contributing editor
Supported by the U.S. Air Force Office of Scientific Research.
- Issue published online: 8 MAR 2005
- Article first published online: 8 MAR 2005
- Manuscript No. 194010. Received December 14, 1993; approved June 17, 1994.
Toughness characteristics of a heterogeneous silicon carbide with a coarsened and elongated grain structure and an intergranular second phase are evaluated relative to a homogeneous, fine-grain control using indentation–strength data. The heterogeneous material exhibits a distinctive flaw tolerance, indicative of a pronounced toughness curve. Quantitative evaluation of the data reveals an enhanced toughness in the long-crack region, with the implication of degraded toughness in the short-crack region. The enhanced long-crack toughness is identified with crack-interface bridging. The degraded short-crack toughness is attributed to weakened grain or interface boundaries and to internal residual stresses from thermal expansion mismatch. A profound manifestation of the toughness-curve behavior is a transition in the nature of mechanical damage in Hertzian contacts, from classical single-crack cone fracture in the homogeneous control to distributed subsurface damage in the heterogeneous material.