HIPing conditions for processing of metal matrix composites using the continuum theory for sintering—I. Theoretical analysis

Olevsky, Eugene A.; Dudek, H.J.; Kaysser, W. A.

doi:10.1016/1359-6454(95)00179-4

Cited by 41 publications

(19 citation statements)

References 12 publications

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“…theoretical basis. [120,121] This is due to particle translation and rotation. In Reference 128, it was shown that smaller particles deform substantially more than larger neighboring particles, and this deformation IV.…”

Section: B 22 Hot Isostatic Pressingmentioning

confidence: 98%

Fundamental aspects of hot isostatic pressing: An overview

Atkinson

Davies

2000

Metall Mater Trans A

593

268

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Hot isostatic pressing (hipping) can be used for upgrading castings, densifying presintered components, consolidating powders, and interfacial bonding. It involves the simultaneous application of a high pressure and elevated temperature in a specially constructed vessel. The pressure is applied with a gas (usually inert) and, so, is isostatic. Under these conditions of heat and pressure, internal pores or defects within a solid body collapse and diffusion bond. Encapsulated powder and sintered components alike are densified to give improved mechanical properties and a reduction in the scatter band of properties.In this article, the basic science of sintering and hipping is summarized and contrasted. The current state of understanding and modeling of hipping is then reviewed. Models can be classified either as microscopic or macroscopic in their approach. In the microscopic approach, the various mechanisms of densification are analyzed in terms of a single particle and its surroundings. In the macroscopic approach, the compact is treated as a continuous medium. In hipping, although the pressure is isostatic, shrinkage is not generally isotropic, particularly if containment is used. However, the shrinkage can now be well predicted, provided that the material and container properties are accurately known.

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Section: B 22 Hot Isostatic Pressingmentioning

confidence: 98%

Fundamental aspects of hot isostatic pressing: An overview

Atkinson

Davies

2000

Metall Mater Trans A

593

268

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“…1 and 2 for three models: Helle±Easterling±Ashby (Helle et al, 1985;Ashby, 1990), Scherer (Scherer, 1979;Bordia and Scherer, 1988) and Skorohod±Olevsky (Skorohod, 1972;Olevsky et al, 1996). Note that the Skorohod±Olevsky model provides values of 2 and P " v intermediate between the two other models.…”

Section: Isothermal Problemmentioning

confidence: 99%

“…Among the models used in this paper we shall present here the one proposed by Skorohod and Olevsky (Olevsky and Skorohod, 1988;Olevsky et al, 1996). This formulation is purely phenomenological although it relies on some micro±macro transition in the linear case.…”

Section: Nonlinear-viscous Porous Materialsmentioning

confidence: 99%

Instability of sintering of porous bodies

Olevsky

Molinari²

2000

International Journal of Plasticity

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Sintering models are discussed and used to analyze¯ow instabilities that may arise during preliminary compaction of powders. These instabilities can be at the origin of heterogeneities in the densi®cation. The material is modeled as a viscoplastic thermal sensitive porous material. The modeling includes the limit case of a linear viscous material. The eects of sintering conditions (temperature and pressure in the case of pressure sintering) and the eects of material characteristics such as porosity, heat capacity, theoretical density, surface tension, particle size and creep parameters on stability of sintering are investigated. The heat release associated with the plastic¯ow is shown to sometimes have an important role. Stability criteria are derived and applied to the analysis of sintering and hot isostatic pressing, using various sintering models. These stability criteria can be used to optimize the densi®cation process; one can control, for example, temperature so as to avoid any instability. Stability maps enabling an optimization of temperature±pressure regime in hot isostatic pressing are built for sample metal (nickel) powder. #

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“…Hence, to describe the continuum properties in modeling the compaction process using methods of continuum mechanics, the sintering theory for porous bodies [3,4], creep theory [5,6], and ideal elastoplastic model [7][8][9][10][11][12][13] are employed. These papers mainly consider the compaction of a strand of unidirectional composite fibers under isostatic or uniaxial pressing.…”

Section: Introductionmentioning

confidence: 99%

Modeling the formation of internal boundaries in an unidirectional fiber strand compacted in plastic state

Borovik

2009

Powder Metall Met Ceram

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The formation of internal boundaries in a unidirectional fiber strand during isostatic and uniaxial pressing in plastic state is studied. The process is modeled using the finite-element method (FEM). An ideal contact elastoplastic problem for a hexagonal fiber strand undergoing plane deformation is solved taking into account friction at the boundaries. For angles of 0°, 30°, 60°, and 90° between the normal to the contact area and the pressing direction, the contact area width, change in the contact area slope, and the radius vector of the cross-sectional boundary of the fiber inside the pore channel as functions of density are determined for the friction coefficient at the boundaries of fibers equal to 0 and 0.5.

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HIPing conditions for processing of metal matrix composites using the continuum theory for sintering—I. Theoretical analysis

Cited by 41 publications

References 12 publications

Fundamental aspects of hot isostatic pressing: An overview

Fundamental aspects of hot isostatic pressing: An overview

Instability of sintering of porous bodies

Modeling the formation of internal boundaries in an unidirectional fiber strand compacted in plastic state

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