Influence of porosity on Young's modulus and Poisson's ratio in alumina ceramics

Asmani, M.; Kermel, Christine; Leriche, Anne; Ourak, Mohamed

doi:10.1016/s0955-2219(00)00314-9

Cited by 255 publications

(137 citation statements)

References 11 publications

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“…These properties correspond to those of continuous alumina Nextele 610 fibres manufactured by 3M (Wilson and Visser, 2001;Asmani et al, 2001). Different cases are considered for the (fully isotropic) soft phase, whose properties are roughly inspired by those of pure aluminium: (i) linear elastic with E m ¼ 70 GPa and m m ¼ 0:345; (ii) ''soft'' linear elastic and almost incompressible with E m ¼ 7 MPa and m m ¼ 0:4999845 (corresponding to the same bulk modulus as in (i)); this choice is motivated by the fact that it corresponds roughly to an elastic description of the next case; (iii) elastoplastic with elastic properties as in (i), an initial yield stress r y of 20 MPa, and a linear isotropic hardening rate H ¼ or flow =o pl of 7 MPa.…”

Section: Constitutive Propertiessupporting

confidence: 65%

Longitudinal deformation of fibre reinforced metals: influence of fibre distribution on stiffness and flow stress

Rossoll

Möser

Mortensen

2005

Mechanics of Materials

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A computational analysis of the longitudinal deformation of continuous fibre reinforced metals is presented. Elastic and elastic-plastic matrix behaviour are considered. Analytical approaches are confronted with finite element analyses (FEA) for varying fibre distributions, ranging from single fibre unit cells to complex cells. Analysis of microfields shows that the main cause for deviation from the equistrain rule of mixtures is a stiffening effect of matrix confinement when surrounded by touching fibres arranged as ''rings''. Comparison with FEA shows that HillÕs [J. Mech. Phys. Solids 12 (1964) 199, 213] bounds, although best possible in terms of volume fraction, are of limited value in so far as HillÕs upper bound lies far above any practical limit for a fibre reinforced material, whereas HillÕs lower bound loses its bounding property when extended to non-linear behaviour via an incremental scheme. This latter effect can be corrected by changing slightly HillÕs derivation in a way that preserves the bounding property. Finally, implications are given for the derivation of in situ matrix flow stress curves from experimental tensile curves on fibre reinforced composites. It is suggested that linear three-point bounds can in practice be used for this purpose.

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Section: Constitutive Propertiessupporting

confidence: 65%

Longitudinal deformation of fibre reinforced metals: influence of fibre distribution on stiffness and flow stress

Rossoll

Möser

Mortensen

2005

Mechanics of Materials

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“…Asmani et al [38] showed that the Poisson's ratio is slightly affected by the fraction of porosity. For example, the authors give a variation between 0.24 and 0.20 for the Poisson's ratio when the porosity varies between 1% and 25%, respectively.…”

Section: Indentation On Massive Materialsmentioning

confidence: 99%

An analysis of the elastic properties of a porous aluminium oxide film by means of indentation techniques

Hemmouche¹,

Chicot²,

Amrouche³

et al. 2013

Materials Science and Engineering: A

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. a b s t r a c tThe elastic modulus of thin films can be directly determined by instrumented indentation when the indenter penetration does not exceed a fraction of the film thickness, depending on the mechanical properties of both film and substrate. When it is not possible, application of models for separating the contribution of the substrate is necessary. In this work, the robustness of several models is analyzed in the case of the elastic modulus determination of a porous aluminium oxide film produced by anodization of an aluminium alloy. Instrumented indentation tests employing a Berkovich indenter were performed at a nanometric scale, which allowed a direct determination of the film elastic modulus, whose value was found to be approximately 11 GPa. However, at a micrometric scale the elastic modulus tends toward the value corresponding to the substrate, of approximately 73 GPa. The objective of the present work is to apply different models for testing their consistency over the complete set of indentation data obtained from both classical tests in microindentation and the continuous stiffness measurement mode in nanoindentation. This approach shows the continuity between the two scales of measurement thus allowing a better representation of the elastic modulus variation between two limits corresponding to the substrate and film elastic moduli. Gao's function proved to be the best to represent the elastic modulus variation.

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“…2. Isso contraria artigos recentes de Asmani et al [13] e Chang et al [30], que correlacionaram a razão de Poisson com a porosidade em uma cerâmica à base de alumina e mostraram uma queda na razão de Poisson com o aumento da porosidade, na faixa de 0 a 25 %-vol. No entanto, a faixa de porosidade trabalhada por esses autores é bastante abaixo da faixa deste trabalho.…”

Section: Resultsunclassified

“…Por outro lado, o valor de m = 0,35 é alto se considerado a alumina densa, porém não se pode descartar uma influência da macroestrutura da espuma sobre essa propriedade, como mostrado no parágrafo anterior pelos trabalhos de Asmani et al [13] e Chang et al [30]. Adotando-se o valor indicado por Dörre e Hübner [16], de um trabalho de Cobles e Kingery para a razão de Poisson da alumina, m = 0,27, a Fig.…”

Section: Resultsunclassified

“…Na hipótese de que um material contém poros com simetria esferoidal, Asmani et al [13] mostram, utilizando uma equação de Boccaccini [14], derivada de um trabalho de Ondracek [15], que a dependência do módulo de Young aparente, E, com a porosidade total, P, pode ser escrita como segue: (F) onde E 0 é o módulo de Young para o material denso (E 0 = 400 GPa para alumina densa [16]) e o expoente s é calculado através de:…”

Section: Dependência Com a Porosidadeunclassified

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Relação entre porosidade e os módulos elásticos de esponjas cerâmicas produzidas via "gelcasting"

et al. 2004

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ResumoA técnica gelcasting , associada à aeração de suspensões cerâmicas, permite a produção de esponjas cerâmicas com uma larga faixa de porosidade. Esponjas à base de alumina foram produzidas com porosidade variando de 62 a 87 %-vol, o que corresponde a densidades relativas entre 0,13 e 0,38. Essas esponjas foram utilizadas para a verificação de modelos, tais como de Mackenzie, de Boccaccini e de Gibson e Ashby, que relacionam a porosidade ou a densidade com os módulos elásticos da cerâmica porosa. Os módulos elásticos de Young, de cisalhamento e a razão de Poisson foram caracterizados através da técnica de ressonância mecânica de barras. Essa técnica permitiu avaliar os valores dos módulos elásticos mesmo com o material tendo macroestrutura celular. Os resultados permitiram verificar qual dos citados modelos oferece melhor descrição do comportamento do módulo elástico em função da porosidade das esponjas cerâmicas. Palavras-chave: cerâmica porosa, gelcasting, módulo elástico, ressonância de barras, alumina. Abstract Broad porosity range can be obtained in ceramic foams employing the gelcasting

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Influence of porosity on Young's modulus and Poisson's ratio in alumina ceramics

Cited by 255 publications

References 11 publications

Longitudinal deformation of fibre reinforced metals: influence of fibre distribution on stiffness and flow stress

Longitudinal deformation of fibre reinforced metals: influence of fibre distribution on stiffness and flow stress

An analysis of the elastic properties of a porous aluminium oxide film by means of indentation techniques

Relação entre porosidade e os módulos elásticos de esponjas cerâmicas produzidas via "gelcasting"

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