Effect of boundary heat flux on columnar formation in binary alloys: A phase-field study

2018 ◽  
Vol 32 (06) ◽  
pp. 1850078 ◽  
Author(s):  
Lifei Du ◽  
Peng Zhang ◽  
Shaomei Yang ◽  
Jie Chen ◽  
Huiling Du
Keyword(s):  
Heat Flux ◽  
Temperature Gradient ◽  
Phase Field ◽  
Phase Field Model ◽  
Solute Diffusion ◽  
Liquid Interfaces ◽  
Cu Alloy ◽  
Temperature Distributions ◽  
Alloy Heat ◽  
Solid Liquid

A non-isothermal phase-field model was employed to simulate the columnar formation during rapid solidification in binary Ni–Cu alloy. Heat flux at different boundaries was applied to investigate the temperature gradient effect on the morphology, concentration and temperature distributions during directional solidifications. With the heat flux input/extraction from boundaries, coupling with latent heat release and initial temperature gradient, temperature distributions are significantly changed, leading to solute diffusion changes during the phase-transition. Thus, irregular columnar structures are formed during the directional solidification, and the concentration distribution in solid columnar arms could also be changed due to the different growing speeds and temperature distributions at the solid–liquid interfaces. Therefore, applying specific heat conditions at the solidifying boundaries could be an efficient way to control the microstructure during solidifications.

Liquid phase stratification induced by large temperature gradient during spinodal decomposition in Fe–Cr alloys: A phase-field study

2021 ◽  
pp. 2150374
Author(s):  
Lifei Du ◽  
Runbo Tian ◽  
Tiantian Shi ◽  
Youqi Cao
Keyword(s):  
Liquid Phase ◽  
Temperature Gradient ◽  
Spinodal Decomposition ◽  
Phase Field ◽  
Anisotropic Diffusion ◽  
Phase Field Model ◽  
Solute Diffusion ◽  
Large Temperature ◽  
Cahn Hilliard Equation ◽  
Kinetics Of

The spinodal decomposition in Fe-40at.%Cr binary alloy is numerically studied by implementing the phase-field model based on Cahn–Hilliard equation. Effects of different temperature gradients on the solute distributing characteristics during the spinodal decomposition are investigated. In the system with a temperature gradient, the phase decomposition happens gradually from low temperature to high temperature, and a metastable stratification is achieved with specified temperature distribution. The critical temperature and corresponding temperature gradient are specified for the obvious solute stratification in the binary Fe–Cr alloy. The kinetics of the solute diffusion during the spinodal decomposition is discussed to reveal the liquid phase stratification induced by the anisotropic diffusion with the nonuniform temperature field. Therefore, tailoring the heat treatment during the spinodal decomposition in Fe–Cr binary alloys might be an efficient way to obtain nanometer coherent microstructures with specified solute distribution.

Phase Field Modeling of Solidification in Single Component Systems

2017 ◽  
Author(s):  
Sepideh Kavousi ◽  
Dorel Moldovan
Keyword(s):  
Heat Flux ◽  
Temperature Gradient ◽  
Power Law ◽  
Phase Field ◽  
Thermal Gradient ◽  
Solidification Rate ◽  
Single Component ◽  
Effect Of Temperature ◽  
Phase Field Modeling ◽  
Field Modeling

Using phase field modeling simulation approach we investigate the effect of various parameters on the primary and secondary dendrite arm spacing during directional solidification in a single component system. In previous studies the effect of temperature gradient was assumed to be negligible in the transversal directions with a temperature rate equal to the product of thermal gradient and solidification rate. In our study the temperature field is obtained from energy conservation equation by considering the balance of latent heat released in the regions where solidification occurs and energy dissipation due to directional temperature gradient as boundary condition. In our simulations, we implemented a numerical method that enables the investigation of solidification in larger domains. Specifically, the temperature and the order parameter equations are solved only in the domains close to the solidification front; approach that reduces the computational costs significantly. We investigate the interplay and the effect of thermal gradient, solidification rate, undercooling temperature, and the cooling heat flux on arm spacing. By using a well-established power law relation the primary and secondary arm spacing are calculated for various solidification parameters. We also show that, for large heat fluxes, the secondary arm spacing is almost constant for different undercooling temperatures; behavior that demonstrates the need for correction of the power law relation by including the effect of heat flux.

A phase field model for a solid–liquid phase transition

2011 ◽  
Vol 38 (7) ◽  
pp. 477-480 ◽  
Author(s):  
Michele Ciarletta ◽  
Mauro Fabrizio ◽  
Vincenzo Tibullo
Keyword(s):  
Phase Transition ◽  
Liquid Phase ◽  
Phase Field ◽  
Field Model ◽  
Phase Field Model ◽  
Liquid Phase Transition ◽  
Solid Liquid

scholarly journals On a phase field model for solid-liquid phase transitions

2012 ◽  
Vol 32 (6) ◽  
pp. 1997-2025 ◽  
Author(s):  
Sylvie Benzoni-Gavage ◽  
◽  
Laurent Chupin ◽  
Didier Jamet ◽  
Julien Vovelle ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Liquid Phase ◽  
Phase Field ◽  
Field Model ◽  
Phase Field Model ◽  
Solid Liquid

2D Phase-Field Simulation of the Directional Solidification Process

2014 ◽  
Vol 704 ◽  
pp. 17-21 ◽  
Author(s):  
Alexandre Furtado Ferreira ◽  
José Adilson de Castro ◽  
Ivaldo Leão Ferreira
Keyword(s):  
Directional Solidification ◽  
Phase Field ◽  
Field Model ◽  
Solid Phase ◽  
Morphological Evolution ◽  
Phase Field Model ◽  
Columnar Dendrite ◽  
Liquid Region ◽  
Field Equations ◽  
Cu Alloy

The microstructure evolution during the directional solidification of Al-Cu alloy is simulated using a phase field model. The transformation from liquid to solid phase is a non-equilibrium process with three regions (liquid, solid and interface) involved. Phase field model is defined for each of the three regions. The evolution of each phase is calculated by a set of phase field equations, whereas the solute in those regions is calculated by a concentration equation. In this work, the phase field model which is generally valid for most kinds of transitions between phases, it is applied to the directional solidification problem. Numerical results for the morphological evolution of columnar dendrite in Al-Cu alloy are in agreement with experimental observations found in the literature. The growth velocity of the dendrite tip and the concentration profile in the solid, interface and liquid region were calculated.

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