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Controlled Surface Flaws in Hot‐Pressed SiC
Author(s) -
PETROVIC J. J.,
JACOBSON L. A.
Publication year - 1976
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1976.tb09381.x
Subject(s) - knoop hardness test , annealing (glass) , materials science , indentation , indentation hardness , composite material , hardness , microstructure
Controlled semi‐elliptical surface flaws were produced in hot‐pressed SiC by Knoop microhardness indentation. Flawed specimens were placed in 4‐point bending in order to determine their critical stress intensity factor, K IC , at both room and high temperatures. Room‐temperature fracture and K IC values after annealing were sensitive to the annealing environment; this behavior correlated with the active/passive nature of the oxidation process. Flaw healing was observed for annealing exposures in air. Room‐temperature K IC values increased with increasing annealing temperature. High‐temperature K IC values decreased with increasing temperature as a result of a decrease in the fracture surface energy.