Yield stress of fine grained materials

Masumura, R.A.; Hazzledine, P. M.; Pande, C. S.

doi:10.1016/s1359-6454(98)00150-5

Cited by 427 publications

(204 citation statements)

References 18 publications

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“…4. The volume of grains follows a log-normal distribution, which has been observed to be reasonable in many metals, alloys and ceramic systems [4,5,43]. Hence, the log-normal distribution is chosen to represent the grain size distribution in the present investigation and may be expressed as,…”

Section: Modelingmentioning

confidence: 99%

“…We consider the grain size distribution which follows a log-normal function. To facilitate the analysis, the following assumptions similar to those specified in [4,8] are used. …”

Section: Modelingmentioning

confidence: 99%

“…'grain size softening' (also called the inverse Hall-Petch relationships) [2]. A number of theories and models have been developed to understand the deviation of the strength from the empirical Hall-Petch equation [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Recent molecular dynamics (MD) simulations have improved our understanding of the deformation of nanocrystalline materials [13].…”

Section: Introductionmentioning

confidence: 99%

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Modeling the dependence of strength on grain sizes in nanocrystalline materials

Bhole

Chen

2008

Science and Technology of Advanced Materials

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A model was developed to describe the grain size dependence of hardness (or strength) in nanocrystalline materials by combining the Hall-Petch relationship for larger grains with a coherent polycrystal model for nanoscale grains and introducing a log-normal distribution of grain sizes. The transition from the Hall-Petch relationship to the coherent polycrystal mechanism was shown to be a gradual process. The hardness in the nanoscale regime was observed to increase with decreasing grain boundary affected zone (or effective grain boundary thickness, ) in the form of −1/2 . The critical grain size increased linearly with increasing . The variation of the calculated hardness value with the grain size was observed to be in agreement with the experimental data reported in the literature.

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Section: Modelingmentioning

confidence: 99%

“…We consider the grain size distribution which follows a log-normal function. To facilitate the analysis, the following assumptions similar to those specified in [4,8] are used. …”

Section: Modelingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Modeling the dependence of strength on grain sizes in nanocrystalline materials

Bhole

Chen

2008

Science and Technology of Advanced Materials

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“…In an attempt to explain nanoscale softening in Cu, Masumara et al [39] has proposed a model involving Coble creep with a threshold stress s 0 that is inversely related to grain size. The equation proposed by Masumara et al is given as [39] s ¼ s 0 þ Bd 3 ½9a…”

Section: Modified Coble Creepmentioning

confidence: 99%

“…[9a] with the equation representing conventional Hall-Petch behavior, Masumara et al [39] predicted that for Cu, the average critical grain size for a transition from hardening to softening is approximately 20 nm. This value is in agreement with the value of 25 nm inferred from experimental data.…”

Section: Modified Coble Creepmentioning

confidence: 99%

Deformation Mechanisms in Nanocrystalline Materials

Mohamed

Yang

2009

Metall Mater Trans A

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As a result of recent investigations on nanocrystalline (nc) materials, extensive experimental data on the deformation behavior of these materials have become available. In this article, an analysis of these data was performed to identify the requirements that a viable deformation mechanism should meet in terms of accounting for the mechanical characteristics and trends that are revealed by the data. The results of the analysis show that a viable deformation mechanism is required to account for the following: (1) an activation volume the value of which is in the range 10 to 40 b 3 ; (2) an activation energy that is close to the activation energy for boundary diffusion but that decreases with increasing applied stress; (3) the magnitudes of deformation rates that cover wide ranges of temperatures, stresses, and grain sizes; (4) inverse Hall-Petch behavior; and (5) limited ductility. The validity of available deformation mechanisms for nc materials is closely examined in the light of these requirements.

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Grain Size Dependence of the Work Hardening Process in Al99.99

Kovács

Chinh

Kovács-Csetényi

2002

phys. stat. sol. (a)

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The work hardening properties of 99.99% purity aluminum were investigated by tensile tests at RT on samples with average grain sizes between 40 and 300 μm. It is shown that the stress–strain curves can only be described by two different functions valid at moderate and at higher strains, respectively. New constitutive equations due to these two different stages are derived on the basis of a new phenomenological model, and their validity is proved by experimental results. It is shown that the work hardening parameters depend strongly on the grain size in the first stage, while the rate of hardening in the second stage is independent of the grain size. The constitutive equations derived are used to analyze the grain size dependence of the flow stress as a function of the strain.

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Yield stress of fine grained materials

Cited by 427 publications

References 18 publications

Modeling the dependence of strength on grain sizes in nanocrystalline materials

Modeling the dependence of strength on grain sizes in nanocrystalline materials

Deformation Mechanisms in Nanocrystalline Materials

Grain Size Dependence of the Work Hardening Process in Al99.99

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