Effect of step-wise change in processing pressure on isolated pore growth during controlled directional solidification in small channels

Cox, Matthew C.; Anilkumar, A. V.; Grugel, R. N.; Lee, Chun P.

doi:10.1016/j.jcrysgro.2008.11.055

Cited by 20 publications

(2 citation statements)

References 21 publications

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“…We also did not consider the rapid development of high-resolution X-ray tomography, in particular for in situ rheology of an alloy maintained in solid-liquid coexistence [264,265] -there is also emerging work for real-time 3D imaging of dendritic growth in thin capillaries [266]. Some direct observations of monotectic solidification [267,268] and gas-pore growth in transparent systems [51,269,270] are of great interest. There still remains a gaping lack of real-time observations in the domain of peritectic growth (see [271] and refs.…”

Section: Conclusion and Prospectsmentioning

confidence: 99%

In situ observation of solidification patterns in diffusive conditions

Akamatsu

Nguyen-Thi

2016

Acta Materialia

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International audienceWe present a review of recent in situ experimentation studies on solidification front patterns and microstructures in alloys. Front-tracking diagnostics and real-time observation methods using high-resolution optical or X-ray imaging devices currently apply to model transparent systems as well as metallic alloys in thin and bulk samples. On a theoretical basis that spans the physics of nonequilibrium pattern formation and materials science, in combination with time-resolved numerical simulations, conclusive results of both fundamental-and applied-science interest have been obtained on major problems relative to multiscale microstructure selection, morphological transitions, and crystallographic effects during single-and multi-phase solidification. We will mainly focus on the dynamics of cellular, dendritic, and eutectic growth patterns in diffusive-growth conditions, that is, in the absence of convection in the liquid. This can be achieved in (semi-)thin samples, or, for bulk solidification, in the reduced-gravity environment of orbiting facilities. A selection of emerging work on, e.g., faceted growth and adaptive control of solidification patterns will furthermore be reported. We conclude by pointing out open questions and ne

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Section: Conclusion and Prospectsmentioning

confidence: 99%

In situ observation of solidification patterns in diffusive conditions

Akamatsu

Nguyen-Thi

2016

Acta Materialia

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“…On the other hand, lotus-type porous metals that contain aligned long columnar pores have recently been functionally fabricated, because they have lightweight, low thermal and electrical conductivities, and high specific tensile strength in the direction parallel to the pore axis (Nakajima, 2007;Park et al 2007;Liu et al 2005). Understanding and controlling pore formation are important (Tane and Nakajima, 2006;Cox et al 2009). Since gas solubility in solid is usually much less than that in liquid, gas is accumulated ahead of the solidification front (Fedorchenko and Chernov, 2003).…”

Section: Introductionmentioning

confidence: 99%

Pore Formation from Bubble Entrapment by a Solidification Front

Wei¹,

Hsiao²

2015

AJHMT

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Mechanism of the pore shape in solid resulted from a tiny bubble captured by a solidification front is theoretically and generally investigated. Pore formation and its shape in solid are one of the most critical factors affecting properties, microstructure, and stresses in materials, and biosciences, global warming, etc. This work is an extension of the previous original work (Wei and Hsiao, 2012) to reveal additional mechanisms. For simplicity without loss of generality, the tiny bubble beyond the solidification front is considered to have a spherical cap, whose contact angle is identical to inclination angle of the pore at the solidification front. The contact angle of the bubble cap is thus governed by the Abel's equation of the first kind in terms of displacement of the solidification front. The controlling parameter is the bubble growth ratesolidification rate ratio. It is found that inclination angle of the pore in the upper region depends on the bubble growth rate-to-solidification rate ratio. Isolated pore cannot occur, provided that contact angle of the bubble cap cannot reach 90 0 . The predicted pore shape and contact angle agree with predictions and observations. Manipulating either bubble growth rate or solidification rate can control pore formation in solid.

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