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Features of Notch Preparation for Fracture Toughness Measurements in Partially Stabilized Zirconia
Author(s) -
Krell Andreas
Publication year - 1994
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.1151-2916.1994.tb07036.x
Subject(s) - materials science , notching , sintering , fracture toughness , cubic zirconia , composite material , indentation , yttria stabilized zirconia , fracture (geology) , ceramic , toughness , tetragonal crystal system , phase (matter) , metallurgy , chemistry , organic chemistry
Fracture toughness measurements with the use of saw cut notches or indentation flaws often give overestimated K Ic values when the flaws are introduced into sintered bodies which contain a metastable phase. Notching before sintering offers a way to eliminate the problem of residual stresses generated by flaw preparation, as has been demonstrated with yttria‐partially‐stabilized tetragonal zirconia. However, the response of each new material to the notching procedure in the unsintered stage has to be considered carefully to exclude possible effects of locally changed den‐sification and grain‐growth kinetics. Untransformable alumina microstructures show similar K Ic values as determined by ISB and SENB methods with 0.1‐mm narrow notches introduced in the green state, and similar K Ic values measured with notches of the same width introduced before and after sintering. Notches introduced before sintering generate the well‐known, rather strong notch width influence on K Ic in the notch width range between 0.1 and 0.2 mm.