Axisymmetric front tracking model for the investigation of grain structure evolution during directional solidification

Battaglioli, Sara; Robinson, A.J.; McFadden, Shaun

doi:10.1016/j.ijheatmasstransfer.2017.07.095

Cited by 9 publications

(7 citation statements)

References 28 publications

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“…• an existing front tracking model for directional solidification of metal alloys [8] was significantly improved by the inclusion of a fluid flow solver for modelling thermal convection either in terrestrial gravity conditions or in hyper-gravity conditions arising during centrifugal casting, hence including the effects of centrifugal and Coriolis forces;…”

Section: Discussionmentioning

confidence: 99%

“…where all the quantities without subscript refer to the mixture of solid and liquid phase. Since the front tracking algorithm is employed to model solidification, it is possible to have control volumes where both a mushy zone and a fully liquid zone are present [8]. In such control volumes, G s represents the overall solid fraction, and can be expressed as…”

Section: Governing Equationsmentioning

confidence: 99%

“…A more detailed description of the model can be found in ref. [8]. The front tracking model allows for the calculation of the volume of columnar mush V m in the control volumes.…”

Section: Solidification Modelmentioning

confidence: 99%

“…On the other hand, several studies show that low temperature gradients combined with high pulling or cooling rates promote the formation of a more extended undercooled region, and hence equiaxed growth [4,5]. Nonetheless, high pulling and cooling rates might induce radial temperature gradients and the development of unwanted radial columnar grains [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…In order to do so, a novel numerical model is proposed. A 2D axisymmetric front tracking algorithm has been recently developed by the author for the solution of directional solidification of cylindrical titanium aluminide samples [8]. In the original model convection in the melt was not treated.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Influence of natural and forced gravity conditions during directional columnar solidification

Battaglioli

Robinson

McFadden

2018

International Journal of Heat and Mass Transfer

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In a recent study, the present authors reported an analysis of a transient process of directional solidification of TiAl alloys in the absence of convection [Battaglioli et al., 2017]. The adopted front tracking model, also coupled with indirect methods for predicting columnar to equiaxed transition (CET), showed how the development of different grain regions, namely axial columnar, radial columnar and equiaxed, depends on process parameters such as temperature distribution and applied cooling rates, as well as on properties such as the degree of inoculation of the melt and nucleation undercooling required for equiaxed growth. In this paper, the previous front tracking model is significantly developed, by including the solution of Navier-Stokes equations in order to predict thermal convection in the liquid region as well as in the columnar mush (treated as an isotropic porous medium). This improvement is introduced with the aim to investigate TiAl alloys solidification under different gravity conditions. Accordingly, the simulation setup employed in the study reproduces the one used in experimental campaigns carried out on the MAXUS 9 sounding rocket (microgravity) and on ESA's Large Diameter Centrifuge (hypergravity), within the framework of ESA's GRADECET (Gravity Dependence of CET in TiAl alloys) project. The ability of the model in predicting thermal convection is demonstrated by considering several case studies. Results show that the evolution of fluid flow patterns in the samples depends on the external forces considered, combined to the transient change of axial and radial temperature gradients that occur during the solidification process. A parametric study of the directional solidification process on a centrifuge is performed by changing the value of the centrifuge arm and rotation rate and results are compared to predictions derived from nondimensional considerations.

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Section: Discussionmentioning

confidence: 99%

Section: Governing Equationsmentioning

confidence: 99%

“…A more detailed description of the model can be found in ref. [8]. The front tracking model allows for the calculation of the volume of columnar mush V m in the control volumes.…”

Section: Solidification Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Influence of natural and forced gravity conditions during directional columnar solidification

Battaglioli

Robinson

McFadden

2018

International Journal of Heat and Mass Transfer

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Thermal cracking prediction for a squeeze casting process with an approach of multi-scale and multi-model coupling

Zhao

Liu

Niu

et al. 2022

Int J Adv Manuf Technol

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The smooth particle hydrodynamics (SPH) method is advantageous in tracking a free surface and a moving interface. This paper uses the SPH method to simulate the filling process of squeeze casting. The simulated temperature field at the end of filling was input into a finite element model (FEM) program to simulate the solidification process after squeeze casting. Due to the existence of a liquid phase, a solid phase, and a two-phase mushy zone in the solidification process after squeeze casting, the deformation behavior in the solidification process was modeled with a thermoelasto-viscoplastic constitutive model representing these different phases. In the RDG thermal cracking criterion based on the principle of dendrite gap complement, there are a strain rate term, a secondary dendritic spacing term, and a pressure term. These terms accurately describe the squeeze casting process. Therefore, the RDG criterion was used to predict thermal cracking. The strain rate term in the RDG criterion was calculated by the FEM. For the calculation of the secondary dendritic spacing, the temperature field during the solidification process is locally refined by the FDM method to complete the transition from the macroscale to the mesoscale; then the refinement results are imported into the phase field method for dendritic growth simulation. The results show that the method based on multi-model coupling has satisfactory prediction accuracy for the thermal cracking in the squeeze casting process. The combination of the phase field method and the RDG criterion provides a new approach to the simulation of thermal cracking defects. The prediction results show that the thermal cracking tendency increases with an increase in strain rate. However, the local position C of the bracket sample had a higher strain rate of 7.15/s, and a lower cooling rate of 2.96 K/s offset the effect of the high strain rate. As a result, a low thermal cracking tendency level of 1.13729 was obtained.

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Prediction of grain-size transition during solidification of hypoeutectic Al-Si alloys by an improved three-dimensional sharp-interface model

Ren

Liu

2022

Computational Materials Science

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Axisymmetric front tracking model for the investigation of grain structure evolution during directional solidification

Cited by 9 publications

References 28 publications

Influence of natural and forced gravity conditions during directional columnar solidification

Influence of natural and forced gravity conditions during directional columnar solidification

Thermal cracking prediction for a squeeze casting process with an approach of multi-scale and multi-model coupling

Prediction of grain-size transition during solidification of hypoeutectic Al-Si alloys by an improved three-dimensional sharp-interface model

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