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Synergistic Effects of Porosity and Glass on Quasi‐Ductility under Hertzian Contact in Liquid‐Phase‐Sintered Alumina
Author(s) -
DiGiovanni Anthony A.,
Chan Helen M.,
Harmer Martin P.,
Nied Herman F.
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.tb01827.x
Subject(s) - materials science , porosity , indentation , composite material , intergranular corrosion , microstructure , phase (matter) , scanning electron microscope , ductility (earth science) , cracking , agglomerate , stress (linguistics) , contact mechanics , creep , finite element method , linguistics , chemistry , philosophy , organic chemistry , physics , thermodynamics
Direct observation of damage mechanisms in a porous liquid‐phase‐sintered alumina under Hertzian contact has been made possible through a modification of the bonded interface technique. Using high‐resolution scanning electron microscopy, subsurface regions have been examined in a pre‐indentation and post‐indentation condition at loads just beyond the yield stress. Intergranular cracking, often through large glassy regions, is observed in the vicinity of pores, whereas dense regions of the microstructure remain undamaged. Distributed subsurface microfracture is attributed to porosity that acts as a stress concentrator and the glassy phase, which provides a weak path for short‐crack propagation.