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Porous Alumina Coating with Tailored Fracture Resistance for Alumina Composites
Author(s) -
O'Brien Michael J.,
Sheldon Brian W.
Publication year - 1999
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.1151-2916.1999.tb02280.x
Subject(s) - materials science , interphase , composite material , microstructure , coating , porosity , composite number , fracture (geology) , scanning electron microscope , fracture mechanics , biology , genetics
A porous Al 2 O 3 coating for Al 2 O 3 composites was prepared by aerosol‐spray deposition of submicrometer‐sized Al 2 O 3 powder. A model composite specimen was hot‐pressed to change the coating's porosity and, thereby, change the interphase fracture resistance. The mixed‐mode fracture resistance of the interphase ranged from 0.5 to 14.8 J/m 2 . The interphase fracture was characterized using electron and acoustic microscopy. Finite‐element analysis (FEA) showed that the testing method possessed a short transient behavior and was immune to asymmetrical cracks. This approach provided a fundamental investigation of the relationships among interphase microstructure, processing, and fracture resistance. The results also provided a detailed test of the He‐Hutchinson criterion for crack deflection.