Sub-10-micrometer toughening and crack tip toughness of dental enamel / Siang Fung Ang; Anja Schulz; Rodrigo Pacher Fernandes; Gerold A. Schneider. Institut für Keramische Hochleistungswerkstoffe

In previous studies, enamel showed indications to occlude small cracks in-vivo and exhibited R-curve behaviors for bigger cracks ex-vivo. This study quantifies the crack tip toughness (KI0, KIII0), the crack closure stress and the cohesive zone size at the crack tip of enamel and investigates the toughening mechanisms near the crack tip down to the length scale of a single enamel crystallite. The crack-opening-displacement (COD) profile of cracks induced by Vickers indents on mature bovine enamel was studied using atomic force microscopy (AFM). The mode I crack tip toughness KI0 of cracks along enamel rod boundaries and across enamel rods exhibit similar range of values: KI0,Ir=0.5-1.6MPa.m0.5 (based on Irwin’s ‘nearfield’ solution) and KI0,cz=0.8-1.5MPa.m0.5 (based on the cohesive zone solution of the Dugdale-Muskhelishvili (DM) crack model). The mode III crack tip toughness KIII0,Ir was computed as 0.02-0.15MPa.m0.5. The crack-closure stress at the crack tip was computed as 163-770MPa with a cohesive zone length and width 1.6-10.1μm and 24-44nm utilizing the cohesive zone solution. Toughening elements were observed under AFM and SEM: crack bridging due to protein ligament and hydroxyapatite fibres (micro- and nanometer scale) as well as microcracks were identified..

Medienart:

E-Book

Erscheinungsjahr:

2011

Erschienen:

Hamburg-Harburg: Univ.-Bibl. der Techn. Univ. Hamburg-Harburg ; 2011

Ausgabe:

[Elektronische Ressource]

Enthalten in:

Zur Gesamtaufnahme

Sprache:

Englisch

Beteiligte Personen:

Ang, Siang Fung, 1981- [Sonstige Person]
Schulz, Anja [asn]
Pacher Fernandes, Rodrigo [asn]
Schneider, Gerold A. [asn]

Links:

Volltext [kostenfrei]
doi.org [kostenfrei]
Volltext

Themen:

Cohesive zone
Crack tip toughness
Enamel
Hierarchical structure
Online-Ressource
Toughening mechanisms
Werkstoffoberflächeneigenschaften

Anmerkungen:

Unterschiede zwischen dem gedruckten Dokument und der elektronischen Ressource können nicht ausgeschlossen werden

Beschreibung:

Systemvoraussetzungen: Internetzugriff, Adobe Reader.

Umfang:

Online-Ressource (PDF-Datei: 12 S., 1.1 MB) ; Ill., graph Darst.

doi:

10.15480/882.990

10.1016/j.jmbbm.2010.12.003

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

646259407