Premium
Acoustic Emission and Microcracking in Sapphire, Sintered Al 2 O 3 , Al/Al 2 O 3 Composite, and Aluminum
Author(s) -
Breval Else,
Srikanth Varanasi,
Subbarao Eleswarapu C.
Publication year - 1995
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.1151-2916.1995.tb08698.x
Subject(s) - materials science , aluminium , sapphire , crystallite , composite material , brittleness , composite number , aluminium oxides , indentation , acoustic emission , phase (matter) , metallurgy , optics , chemistry , physics , organic chemistry , catalysis , laser , biochemistry
A range of materials with brittle to ductile behavior (single‐crystal and polycrystalline alumina, aluminum/alumina composite, and metallic aluminum) were investigated by acoustic emission (AE) methods for microcracking during hardness indentations or cooling from elevated temperatures (800°C). During indentation, the extent of crack formation (and the AE counts) decreased in the following order: sapphire, sintered alumina, aluminum/alumina composite with no microcracking in metallic aluminum. During cooling from 800°C, polycrystalline alumina exhibited more extensive microcracking than the aluminum/alumina composite, suggesting that the metallic phase in the aluminum/alumina composite absorbs stresses more than the glassy boundary phase in sintered alumina.