A Phase-Field Model for Rapid Solidification with Non-Equilibrium Solute Diffusion

2015 ◽  
Vol 817 ◽  
pp. 14-20
Author(s):  
Hai Feng Wang ◽  
Cun Lai ◽  
Xiao Zhang ◽  
Kuang Wang ◽  
Feng Liu
Keyword(s):  
Rapid Solidification ◽  
Phase Field ◽  
Growth Velocity ◽  
Field Model ◽  
Phase Field Model ◽  
Solute Diffusion ◽  
Current Phase ◽  
Diffusion Velocity ◽  
Good Agreement ◽  
Non Equilibrium

Since the growth velocity can be comparable with or even larger than the solute diffusion velocity in the bulk phases, modeling of rapid solidification with non-equilibrium solute diffusion becomes quite an important topic. In this paper, an effective mobility approach was proposed to derive the current phase field model (PFM). In contrast with the previous PFMs that were derived by the so-called kinetic energy approach, diffusionless solidification happens not only in the bulk phases but also inside the interface when the growth velocity is equal to the solute diffusion velocity in liquid. A good agreement between the model predictions and experimental results is obtained for rapid solidification of Si-9at.%As alloy.

scholarly journals Modelling of Microstructure Evolution during Laser Processing of Intermetallic Containing Ni-Al Alloys

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1051
Author(s):  
Mohammad Amin Jabbareh ◽  
Hamid Assadi
Keyword(s):  
Additive Manufacturing ◽  
Rapid Solidification ◽  
Microstructure Evolution ◽  
Phase Field ◽  
Laser Processing ◽  
Field Model ◽  
Phase Field Model ◽  
Intermetallic Phases ◽  
Al Alloy ◽  
Kinetic Effects

There is a growing interest in laser melting processes, e.g., for metal additive manufacturing. Modelling and numerical simulation can help to understand and control microstructure evolution in these processes. However, standard methods of microstructure simulation are generally not suited to model the kinetic effects associated with rapid solidification in laser processing, especially for material systems that contain intermetallic phases. In this paper, we present and employ a tailored phase-field model to demonstrate unique features of microstructure evolution in such systems. Initially, the problem of anomalous partitioning during rapid solidification of intermetallics is revisited using the tailored phase-field model, and the model predictions are assessed against the existing experimental data for the B2 phase in the Ni-Al binary system. The model is subsequently combined with a Potts model of grain growth to simulate laser processing of polycrystalline alloys containing intermetallic phases. Examples of simulations are presented for laser processing of a nickel-rich Ni-Al alloy, to demonstrate the application of the method in studying the effect of processing conditions on various microstructural features, such as distribution of intermetallic phases in the melt pool and the heat-affected zone. The computational framework used in this study is envisaged to provide additional insight into the evolution of microstructure in laser processing of industrially relevant materials, e.g., in laser welding or additive manufacturing of Ni-based superalloys.

Phase Field Model for Influence of Edge Dislocation on Precipitation

2011 ◽  
Vol 415-417 ◽  
pp. 1482-1485
Author(s):  
Chuang Gao Huang ◽  
Ying Jun Gao ◽  
Li Lin Huang ◽  
Jun Long Tian
Keyword(s):  
Edge Dislocation ◽  
Phase Field ◽  
Field Model ◽  
Phase Field Model ◽  
Field Method ◽  
Phase Field Method ◽  
Second Phase ◽  
Free Energy Function ◽  
Phase Nucleation ◽  
Good Agreement

The second phase nucleation and precipitation around the edge dislocation are studied using phase-field method. A new free energy function is established. The simulation results are in good agreement with that of theory of dislocation and theory of non-uniform nucleation.

scholarly journals Non-equilibrium Thermodynamical Description of Superfluid Transition in Liquid Helium

2017 ◽  
Vol 42 (4) ◽  
Author(s):  
Lucia Ardizzone ◽  
Maria Stella Mongiovì ◽  
Lidia Saluto
Keyword(s):  
Liquid Helium ◽  
Phase Field ◽  
Field Model ◽  
Phase Field Model ◽  
Superfluid Transition ◽  
Non Equilibrium

AbstractIn previous papers a phase field model for

Solute trapping and solute drag in a phase-field model of rapid solidification

1998 ◽  
Vol 58 (3) ◽  
pp. 3436-3450 ◽  
Author(s):  
N. A. Ahmad ◽  
A. A. Wheeler ◽  
W. J. Boettinger ◽  
G. B. McFadden
Keyword(s):  
Rapid Solidification ◽  
Phase Field ◽  
Field Model ◽  
Phase Field Model ◽  
Solute Drag ◽  
Solute Trapping

scholarly journals A Phase-Field Study of Microstructure Evolution in Tungsten Polycrystalline under He/D Irradiation

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7433
Author(s):  
You-Sung Han
Keyword(s):  
Fractal Dimension ◽  
Phase Field ◽  
Field Model ◽  
Empirical Relation ◽  
Phase Field Model ◽  
Current Phase ◽  
Dimension Analysis ◽  
Irradiation Energy ◽  
Fractal Dimension Analysis ◽  
Growth Of Voids

Analyses in the present study focus on understanding the evolution of the tungsten microstructure under He/D irradiation. A fractal dimension analysis was utilized to characterize the structural pattern of the microstructure irradiated by both low (10–80 eV) and high (8–30 keV) irradiation energy. All examined W microstructures show a direct correlation between the fractal dimension and irradiation energy. Analyses establish an empirical relation expressing a change in the microstructure as a function of the irradiation energy based on the changes in the fractal dimension of the microstructures. The proposed relation was implemented in the phase-field model formulation with an account of the interfacial energy induced by the crystallographic mismatch between grains under irradiation. The current phase-field model captures the evolution of the void under irradiation, including nucleation and the growth of voids, and sink efficiency for vacancy annihilation in the vicinity of grain boundaries.

Phase Field Modeling of Solute Trapping in a Al-Sn Alloy during Rapid Solidification

2014 ◽  
Vol 794-796 ◽  
pp. 740-745 ◽  
Author(s):  
Xiong Yang ◽  
Li Jun Zhang ◽  
Yong Du
Keyword(s):  
Rapid Solidification ◽  
Phase Field ◽  
Field Model ◽  
Kinetic Equations ◽  
Phase Field Model ◽  
Interface Velocity ◽  
Interface Energy ◽  
Phase Field Simulation ◽  
Solute Trapping ◽  
Field Simulation

During rapid solidification, interfaces are often driven far from equilibrium and the "solute trapping" phenomenon is usually observed. Very recently, a phase field model with finite interface dissipation, in which separate kinetic equations are assigned to each phase concentration instead of an equilibrium partitioning condition, has been newly developed. By introducing the so-called interface permeability, the phase field model with finite interface dissipation can nicely describe solute trapping during solidification in the length scale of micrometer. This model was then applied to perform a phase field simulation in a Al-Sn alloy (Al-0.2 at.% Sn) during rapid solidification. A simplified linear phase diagram was constructed for providing the reliable driving force and potential information. The other thermophysical parameters, such as interface energy and diffusivities, were directly taken from the literature. As for the interface mobility, it was estimated via a kinetic relationship in the present work. According to the present phase field simulation, the interface velocity increases as temperature decreases, resulting in the enhancement of solute trapping. Moreover, the simulated solute segregation coefficients in Al-0.2 at.% Sn can nicely reproduce the experimental data.

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