Title

A further insight into spherical indentation: Ring crack formation in a brittle La0.8Sr0.2Ga0.8Mg0.2O3 perovskite

Authors

Authors

M. Lugovy; V. Slyunyayev; S. Yarmolenko; J. Sankar; T. Graule; J. Kuebler; D. Nicholson;N. Orlovskaya

Comments

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Abbreviated Journal Title

Acta Mater.

Keywords

Microindentation; Perovskites; Fracture; Modeling; STRESS INTENSITY FACTORS; METAL-MATRIX COMPOSITES; PORE-SIZE; MEASUREMENT; HERTZIAN INDENTATION; FRACTURE-TOUGHNESS; RECRYSTALLIZED; SILICONCARBIDE; RESIDUAL-STRESS; SURFACE-ENERGY; CONE CRACKS; DAMAGE; Materials Science, Multidisciplinary; Metallurgy & Metallurgical; Engineering

Abstract

It is known that theoretical considerations of fracture under loading by a spherical indenter are based on the concept of pre-existing cracks. However, nucleation and growth of the critical crack could occur during indentation, as happens during microcracking. The goal of the presented research is to develop a new concept of fracture under spherical indentation in a brittle elastic material taking into account the possibility of critical crack nucleation and growth during loading. La0.8Sr0.2Ga0.8Mg0.2O3 (LSGM) perovskite has been chosen as a polycrystalline elastic low fracture toughness ceramic to perform indentation using a tungsten carbide spherical indenter. Experimental measurements of ring crack radii for well-polished LSGM cannot be explained within the framework of the pre-existing crack hypothesis. The local risk calculated using the concept of pre-existing cracks gives a most probable range of ring crack radii that does not match the radii measured experimentally. However, the local risk calculated using the assumption of critical crack nucleation and formation during spherical indentation results in a most probable range of ring crack radii which exhibits good agreement with the experimental data. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Journal Title

Acta Materialia

Volume

59

Issue/Number

11

Publication Date

1-1-2011

Document Type

Article

Language

English

First Page

4425

Last Page

4436

WOS Identifier

WOS:000291567900018

ISSN

1359-6454

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