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Determination of Fracture Toughness at High Temperatures after Subcritical Crack Extension
Author(s) -
Fett Theo,
Munz Dietrich
Publication year - 1992
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.1151-2916.1992.tb04399.x
Subject(s) - fracture toughness , materials science , stress intensity factor , composite material , fracture mechanics , fracture (geology) , creep , ceramic , crack growth resistance curve , stress (linguistics) , crack closure , linguistics , philosophy
As a consequence of R ‐curve behavior, ceramic materials may exhibit increased fracture toughness ( K Ic ) following slow crack extention. In this investigation, the effect of crack propagation on fracture toughness is studied in static bending tests. For the calculation of stress intensity factors ( K I ) the stress distribution must be known at the moment of fracture. As a consequence of creep, this stress distribution must deviate from the linear distribution. The corresponding stress intensity factors are computed using the fracture mechanical weight function. Experimental results for fracture toughness are communicated for a 2.5%‐MgO‐doped hot‐pressed Si 3 N 4 at 1300°.