Using the Phase Field Method to Investigate Microstructural Evolution of Semi-Solid 357.0 Slurries

2019 ◽  
Vol 285 ◽  
pp. 367-372
Author(s):  
Wen Ying Qu ◽  
Da Quan Li ◽  
Zhi Peng Guo ◽  
Min Luo ◽  
Fan Zhang ◽  
...  
Keyword(s):  
Microstructural Evolution ◽  
Phase Field ◽  
Isothermal Condition ◽  
Field Method ◽  
Spherical Particles ◽  
Phase Field Method ◽  
Solid Alloy ◽  
Solid Region ◽  
Semi Solid ◽  
Solidification Microstructures

Semi-solid aluminum slurries have globular grains, different from traditional dendritic solidification microstructures. The mechanism responsible for the formation of these globular grains is still in dispute. Some researchers suggest that the globular grains are formed by fractured dendrites, while others report it is due to copious nucleation. This study will model the growth of the α-Al phase during the production of semi-solid slurries using the swirled equilibrium enthalpy device (SEED) process, where liquid alloy with a low superheat is poured into a steel crucible and swirled within the semi-solid region. Experimental observations have shown that the final microstructure of the slurry produced by the SEED process is relatively non-uniform, with large dendrites at surface and fine spherical particles at the center. Open source code for the phase field method has been adopted to simulate the different microstructural evolution for semi-solid alloy 357.0. The effect of localized temperatures under isothermal condition on the morphology of the α-Al particles has been investigated according to the special conditions of the SEED process. In addition, suggestions for modifying the slurry production to achieve more uniform microstructure are discussed.

scholarly journals Simulation of the External Pressure Influence on the Micro-Structural Evolution of a Single Crystal Ni-Based Superalloy

2011 ◽  
Vol 278 ◽  
pp. 247-252
Author(s):  
Inmaculada Lopez-Galilea ◽  
Stephan Huth ◽  
Suzana Gomes Fries ◽  
Ingo Steinbach ◽  
Werner Theisen
Keyword(s):  
Single Crystal ◽  
Microstructural Evolution ◽  
Phase Field ◽  
Structural Evolution ◽  
Field Method ◽  
External Pressure ◽  
Experimental Results ◽  
Alloying Elements ◽  
Phase Field Method

The phase field method has been applied to simulate the microstructural evolution of a commercial single crystal Ni-based superalloy during both, HIP and annealing treatments. The effects of applying high isostatic pressure on the microstructural evolution, which mainly retards the diffusion of the alloying elements causing the loss of the orientational coherency between the phases is demonstrated by the simulation and experimental results

scholarly journals Simulation of the Microstructural Evolution of Pure Material and Alloys in an Undercooled Melts via Phase-field Method and Adaptive Computational Domain

2015 ◽  
Vol 18 (3) ◽  
pp. 644-653 ◽  
Author(s):  
Alexandre Furtado Ferreira ◽  
Ivaldo Leão Ferreira ◽  
Janaan Pereira da Cunha ◽  
Ingrid Meirelles Salvino
Keyword(s):  
Microstructural Evolution ◽  
Phase Field ◽  
Field Method ◽  
Phase Field Method ◽  
Computational Domain ◽  
Pure Material ◽  
Undercooled Melts

scholarly journals Effect of Al Concentration on the Microstructural Evolution of Fe-Cr-Al Systems: A Phase-Field Approach

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 4
Author(s):  
Jeonghwan Lee ◽  
Kwangheon Park ◽  
Kunok Chang
Keyword(s):  
Microstructural Evolution ◽  
Phase Field ◽  
Three Dimensional ◽  
Field Method ◽  
Phase Fraction ◽  
Phase Field Method ◽  
Processing Unit ◽  
Computing Technique ◽  
Α Phase ◽  
2D And 3D

In this study, the microstructural evolution of an Fe-Cr-Al system was simulated in two-dimensional (2D) and three-dimensional (3D) systems using the phase-field method. We investigated the effect of Al concentration on the microstructural evolution of the systems, with a focus on the nucleation and growth of the Cr-rich α′ phase. In addition, we quantitatively analyzed the mechanism of the effect of Al concentration on the microstructural characteristics of the 2D and 3D systems, such as the number of precipitates, average precipitate area (volume), and α′ phase fraction. In particular, we analyzed the effect of Al concentration and the dimensions of the system cell on the formation of the interconnected structure at high Cr concentrations, such as 35 Crat% and 40 Crat%. To enhance the performance of the simulations, we applied a semi-implicit Fourier spectral method for the ternary system and a parallel graphics processing unit computing technique. The results revealed that the initiation of phase separation in the 2D and 3D simulations was enhanced with an increase in the average Al concentration in the system. In addition, with an increase in the average Al concentration in both systems, the α′ phase fraction increased, while the change in the phase fraction decreased.

scholarly journals Permeability Measurements of 3D Microstructures Generated by Phase Field Simulation of the Solidification of an Al-Si Alloy during Chill Casting

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1895
Author(s):  
Ralf Berger ◽  
Markus Apel ◽  
Gottfried Laschet ◽  
Wilhelm Jessen ◽  
Wolfgang Schröder ◽  
...  
Keyword(s):  
Phase Field ◽  
Domain Walls ◽  
Dynamical Evolution ◽  
3D Models ◽  
Field Method ◽  
Phase Field Method ◽  
Fused Filament Fabrication ◽  
Model Fluid ◽  
Semi Solid ◽  
Computational Fluid Flow

The permeability of the semi-solid state is important for the compensation of volume shrinkage during solidification, since insufficient melt feeding can cause casting defects such as hot cracks or pores. Direct measurement of permeability during the dynamical evolution of solidification structures is almost impossible, and numerical simulations are the best way to obtain quantitative values. Equiaxed solidification of the Al-Si-Mg alloy A356 was simulated on the microscopic scale using the phase field method. Simulated 3D solidification structures for different stages along the solidification path were digitally processed and scaled up to generate 3D models by additive manufacturing via fused filament fabrication (FFF). The Darcy permeability of these models was determined by measuring the flow rate and the pressure drop using glycerol as a model fluid. The main focus of this work is a comparison of the measured permeability to results from computational fluid flow simulations in the phase field framework. In particular, the effect of the geometrical constraint due to isolated domain walls in a unit cell with a periodic microstructure is discussed. A novel method to minimize this effect is presented. For permeability values varying by more than two orders of magnitude, the largest deviation between measured and simulated permeabilities is less than a factor of two.

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