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Indentation‐Induced Contact Deformation and Damage of Glasslike Carbon
Author(s) -
Sakai Mototsugu,
Hanyu Hiroyuki,
Inagaki Michio
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.tb08429.x
Subject(s) - indentation , materials science , composite material , brittleness , deformation (meteorology) , contact mechanics , ceramic , vickers hardness test , fracture (geology) , pressing , fracture mechanics , indentation hardness , microstructure , structural engineering , finite element method , engineering
Fracture mechanics are examined for the Vickers‐indentation‐induced contact deformation and damage of glassy carbons produced by different densification processes. The indentation load versus indentation depth relationship during the loading‐unloading cycle reveals that the contact deformation is purely elastic even under such a sharp indentation, which subsequently leads to an indentation‐induced ring/cone crack system instead of the median/radial crack system. The processes and mechanisms of such an anomalous surface crack system are related to the very open microstructure of glassy carbons. The ring/cone cracks induced by Vickers indentation are, however, significantly different in nature from the well‐known Hertzian cone crack which is induced by pressing a spherical indenter on a brittle surface. Demonstrated is the superiority of glassy carbons to ordinary brittle ceramic materials in resistance to strength degradation by contact with hard particles such as in ballistic situations.