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Interfacial Fracture Phenomena in Ceramic Composite Directionally Solidified Eutectics with a Ductile Interphase
Author(s) -
Alem Nasim,
Dravid Vinayak P.
Publication year - 2006
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.1551-2916.2005.00786.x
Subject(s) - materials science , eutectic system , interphase , composite material , scanning electron microscope , ceramic , metal , indentation , composite number , microstructure , metallurgy , genetics , biology
Interphase interfaces in Ni x Co 1− x O/ZrO 2 (CaO) directionally solidified eutectics (DSEs) are modified by selective chemical reduction of the Ni x Co 1− x O oxide phase. Scanning electron microscopy studies of such Ni x Co 1− x O/ZrO 2 (CaO) DSEs show formation of a thin layer of metallic Ni(Co) interphase (∼100 nm) and interfacial porosity upon reduction at high temperatures. A significant change is observed in the mechanical behavior of the reduced Ni x Co 1− x O/ZrO 2 (CaO) DSEs compared with its pristine counterpart, which is largely attributed to the formation of metallic Ni(Co) interphases. Indentation fracture studies indicate that the presence of metallic interphases in the DSEs enhance the stress energy release mechanism through plastic deformation, interfacial delamination, crack arrest, and crack bridging across the metallic interphase after reduction.