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Stress–Strain Behavior of Alumina, Magnesia‐Partially‐Stabilized Zirconia, and Duplex Ceramics and Its Relevance for Flaw Resistance, K R ‐Curve Behavior, and Thermal Shock Behavior
Author(s) -
Lutz Ekkehard H.,
Swain Michael V.
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.tb04386.x
Subject(s) - thermal shock , materials science , brittleness , ductility (earth science) , composite material , ceramic , toughening , cubic zirconia , shock (circulatory) , toughness , creep , medicine
The stress–strain behavior for Al 2 O 3 of different grain size, for three different Mg‐PSZ grades, and for various differently composed duplex structures is investigated and compared with their flaw resistance, K R ‐curve behavior, and thermal shock behavior measured in previous works. The experimental results seem to reveal that, for most materials, quasi ductility increases with increasing flaw resistance, increasingly pronounced K R ‐curve behavior, and increasing thermal shock retained strength. However, brittle ceramics can exhibit rising K R ‐curves, whereas pronounced quasiductile materials can exhibit flat K R ‐curves. An explanation for the apparent pseudo relationship between quasi ductility and K R ‐curve behavior may be that, apart from genuine transformation ductility, most quasi‐ductile effects such as microcracking have only a minor contribution to rising R ‐curve behavior, but require the existence of strong residual stresses, which are, on the other hand, responsible for the occurrence of most toughening mechanisms. Also discussed is the influence of microcracking on flaw resistance and thermal shock strength degradation.