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Titolo:
Fracture toughness of ceramics and semi-brittle alloys using a miniaturized disk-bend test
Autore:
Chen, FC; Ardell, AJ;
Indirizzi:
Univ Calif Los Angeles, Dept Mat Sci & Engn, Los Angeles, CA 90095 USA Univ Calif Los Angeles Los Angeles CA USA 90095 Los Angeles, CA 90095 USA TRW Space & Elect Grp, Redondo Beach, CA 90278 USA TRW Space & Elect Grp Redondo Beach CA USA 90278 ondo Beach, CA 90278 USA
Titolo Testata:
MATERIALS RESEARCH INNOVATIONS
fascicolo: 5, volume: 3, anno: 2000,
pagine: 250 - 262
SICI:
1432-8917(200006)3:5<250:FTOCAS>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
CRACK-GROWTH-RESISTANCE; FINITE-ELEMENT ANALYSIS; MECHANICAL-PROPERTIES; INDENTATION FRACTURE; STRESS MEASUREMENTS; TENSILE PROPERTIES; STRENGTH; MICROSTRUCTURE; ALUMINA; TI5SI3;
Keywords:
small-specimen testing; controlled-flaw method; fracture toughness; brittle materials; finite element analysis;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Engineering, Computing & Technology
Citazioni:
45
Recensione:
Indirizzi per estratti:
Indirizzo: Ardell, AJ Univ Calif Los Angeles, Dept Mat Sci & Engn, Los Angeles, CA 90095 USA Univ Calif Los Angeles Los Angeles CA USA 90095 , CA 90095 USA
Citazione:
F.C. Chen e A.J. Ardell, "Fracture toughness of ceramics and semi-brittle alloys using a miniaturized disk-bend test", MAT RES INN, 3(5), 2000, pp. 250-262

Abstract

We review herein the measurement of the fracture toughness of brittle and semi-brittle materials via the controlled-flow method in combination with the miniaturized disk-bend test (MDBT). The specimens utilized are disks 3 mm in diameter and typically range in thickness from 250 to 400 mu m Each specimen is metallographically polished and indented in its center under a known load, F, using a Vickers indenter. The disk is then subjected to biaxial loading, with the indented side ill tension, and tested to failure. The fracture stress, sigma(f), is calculated from a standard formula if the material is completely brittle, or determined using finite element analysis if the material experiences limited plasticity prior to fracture. Values of the fracture toughness are then obtained by analyzing the data on sigma(f) vs. F using established equations of fracture mechanics. This includes the empirical relation between fracture resistance, K-R(c), and crack length, c,K-R(c) = K-infinity - Q/c(3/2),where Q is a constant and K-infinity is the crack resistance at "infinite"crack length. It is convincingly shown that this so-called R-curve equation correctly predicts K-infinity, which is comparable to the conventionally measured Mode I plain-strain fracture toughness, K-Ic, of the same material. The fundamental constants in the fracture-mechanics-based equations are discussed, emphasizing the aspects pertinent to the small specimens used in the MDBT. Results are presented on 8 materials: ZnS, glass-ceramic, Si3N4, Ti5Si3, SiC, Ni3Ge, NiAl and Ti-46.5Al-2.1Cr-3.0Nb-0.2W. All are brittle except for the latter two, which undergo slight plastic deformation before fracturing. The resulting values of K-infinity are in excellent agreement with published values derived from conventional measurements, providing considerable confidence in the method.

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Documento generato il 07/07/20 alle ore 15:36:53