Investigation of Spinodal Decomposition in Fe-Cr Alloys: CALPHAD Modeling and Phase Field Simulation

2011 ◽  
Vol 172-174 ◽  
pp. 1060-1065 ◽  
Author(s):  
Wei Xiong ◽  
Klara Asp Grönhagen ◽  
John Ågren ◽  
Malin Selleby ◽  
Joakim Odqvist ◽  
...  
Keyword(s):  
Spinodal Decomposition ◽  
Phase Field ◽  
Accurate Determination ◽  
Enthalpy Of Mixing ◽  
Field Method ◽  
Phase Field Method ◽  
Phase Field Simulation ◽  
Mobility Data ◽  
Field Simulation ◽  
Calphad Modeling

This work is dedicated to simulate the spinodal decomposition of Fe-Cr bcc (body centered cubic) alloys using the phase field method coupled with CALPHAD modeling. Thermodynamic descriptions have been revised after a comprehensive review of information on the Fe-Cr system. The present work demonstrates that it is impossible to reconcile the ab initio enthalpy of mixing at the ground state with the experimental one at 1529 K using the state-of-the-art CALPHAD models. While the phase field simulation results show typical microstructure of spinodal decomposition, large differences have been found on kinetics among experimental results and simulations using different thermodynamic inputs. It was found that magnetism plays a key role on the description of Gibbs energy and mobility which are the inputs to phase field simulation. This work calls for an accurate determination of the atomic mobility data at low temperatures.

Phase-Field Modeling of Morphological Change of Ferrite during Decomposition of Austenite in Fe-C Alloy

2007 ◽  
Vol 345-346 ◽  
pp. 935-938
Author(s):  
A. Yamanaka ◽  
Tomohiro Takaki ◽  
Yoshihiro Tomita
Keyword(s):  
Morphological Change ◽  
Phase Field ◽  
Numerical Approach ◽  
Field Method ◽  
Homogenization Method ◽  
Ferrite Phase ◽  
Phase Field Method ◽  
Element Analysis ◽  
Phase Field Simulation ◽  
Field Simulation

The integrated simulation model for microstructural design of Fe-C alloy using the phase-field method and the homogenization method is proposed. First, the phase-field simulation is performed to simulate the morphological change of the grain boundary ferrite to Widmanstätten ferrite. Then, in order to clarify the effects of the morphology of the ferrite phase on the micro- and macroscopic mechanical properties, the finite element analysis based on the homogenization method is conducted with the representative volume element obtained from the phase-field simulation. This numerical approach provides a powerful tool to investigate systematically the micro and macroscopic mechanical behavior with the morphological change of the ferrite phase in the Fe-C alloy.

Phase Field Simulation of Rafting Behavior of γ`Phase in Nickel Base Superalloy

2008 ◽  
Vol 33-37 ◽  
pp. 471-476 ◽  
Author(s):  
Akiyuki Takahashi ◽  
Yutaka Kobayashi ◽  
Masanori Kikuchi
Keyword(s):  
Network Model ◽  
Phase Field ◽  
Lattice Misfit ◽  
Field Method ◽  
Phase Field Method ◽  
Dislocation Network ◽  
Nickel Base Superalloy ◽  
Interfacial Dislocation ◽  
Phase Field Simulation ◽  
Field Simulation

This paper describes phase field simulations of the rafting behavior of γ’ phase with a simple interfacial dislocation network model. The interfacial dislocation network model accounts for the effect of the network on the lattice misfit between γ and γ’ phases and the subsequent rafting behavior. The model is implemented into the phase field simulation to see the dependence of the rafting behavior of γ’ phases on the interfacial dislocation network. Without the dislocation network model, the amount of the rafting was negligibly small. On the other hand, with the dislocation network model, the γ’ phases shows a large amount of rafting, which is in good agreement with the results of the experimental observations. Therefore, the combination of the phase field method and the simple interfacial dislocation network model developed in this work is appropriate for the simulation of the rafting of γ’ phases.

A Phase-Field Simulation of Nucleation from Subgrain and Grain Growth in Static Recrystallization

2008 ◽  
Vol 584-586 ◽  
pp. 1045-1050 ◽  
Author(s):  
Mayu Muramatsu ◽  
Yuichi Tadano ◽  
Kazuyuki Shizawa
Keyword(s):  
Phase Field ◽  
Reaction Diffusion ◽  
Computational Procedure ◽  
Field Method ◽  
Phase Field Method ◽  
Phase Field Simulation ◽  
Field Simulation ◽  
Nucleus Growth ◽  
Reaction Diffusion Model ◽  
Three Stages

A new recrystallization phase-field method is proposed, in which the three stages of recrystallization phenomena, i.e., recovery, nucleation and nucleus growth are sequentially taken into account in a computation. From the information of subgrain patterns and crystal orientations in a polycrystal that are obtained by a dislocation-crystal plasticity FE analysis based on a reaction-diffusion model, subgrain groups surrounded by high angle boundary are found out. Next, subgrains in the group are coalesced into a nucleus by rotation of crystal orientation and migration of subgrain boundaries through a phase-field simulation. Then a computation of nucleus growth is performed also using the phase-field method on account of an autonomic incubation period of nucleation, in which stored dislocation energy assumes a role of driving force. It is shown that the present method can numerically reproduce the three stages of recrystallization as a sequence of computational procedure.

scholarly journals The Effects of Inhomogeneous Elasticity and Dislocation on Thermodynamics and the Kinetics of the Spinodal Decomposition of a Fe-Cr System: A Phase-Field Study

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1209
Author(s):  
Wooseob Shin ◽  
Jeonghwan Lee ◽  
Kunok Chang
Keyword(s):  
Spinodal Decomposition ◽  
Phase Field ◽  
Early Stage ◽  
Field Method ◽  
Phase Field Method ◽  
Precipitate Size ◽  
System A ◽  
Phase Separation Kinetics ◽  
Cr Concentration ◽  
Cr System

The effects of inhomogeneous elasticity and dislocation on the microstructure evolution of α′ precipitate in a Fe-Cr system was investigated using a Computer Coupling of Phase Diagrams and Thermochemistry (CALPHAD)-type free energy incorporated phase-field method. In order to simulate the precipitation behavior by phase-field modeling in consideration of inhomogeneous elasticity, a Multiphysics Object-Oriented Simulation Environment (MOOSE) framework was used, which makes it easy to use powerful numerical means such as parallel computing and finite element method (FEM) solver. The effect of inhomogeneous elasticity due to the compositional inhomogeneity or the presence of dislocations affects the thermodynamic properties of the system was investigated, such as the lowest Cr concentration at which spinodal decomposition occurs. The effect of inhomogeneous elasticity on phase separation kinetics is also studied. Finally, we analyzed how inhomogeneous elasticity caused by compositional fluctuation or dislocation affects microstructure characteristics such as ratio between maximum precipitate size with respect to the average on early stage and later stage, respectively.

Phase Field Simulation of the Pure Material Dendrite Growth in a Forced Flow

2012 ◽  
Vol 571 ◽  
pp. 3-7
Author(s):  
Jing Liu ◽  
Ying Shuo Wang
Keyword(s):  
Phase Field ◽  
Vertical Direction ◽  
Field Method ◽  
Dendritic Morphology ◽  
Forced Flow ◽  
Phase Field Method ◽  
Pure Material ◽  
Phase Field Models ◽  
Field Simulation ◽  
Control Equation

The phase field method is effective in simulating the formation of solidification microstructure. Based on the phase field models of coupling flow field and noise field proposed by Tong and Beckermann, using finite difference method to solve control equation, apartly simulating the dendritic morphology under the condition of convection or none convection, and drawing the following conclusions after comparing the results: in the side, the dendrite will no longer be symmetrical under the condition of countercurrent and downstream, the dendrite tip grows faster with countercurrent than that of the latter, while the dendrite grows almost naturally in the vertical direction of convection.

Numerical Simulation of Spinodal Deposition in Cu–6at.%Ni–3at.%Si Ternary Alloy Using of Phase Field Method

2011 ◽  
Vol 704-705 ◽  
pp. 1410-1415 ◽  
Author(s):  
Yong Qiang Long ◽  
Ping Liu ◽  
Yong Liu ◽  
Shu Guo Jiao ◽  
Bao Hong Tian
Keyword(s):  
Spinodal Decomposition ◽  
Ternary Alloy ◽  
Phase Field ◽  
Elastic Energy ◽  
Early Stage ◽  
Phase Field Model ◽  
Field Method ◽  
Phase Field Method ◽  
Growth Exponent ◽  
Dynamics Calculation

Based on Cahn-Hilliard nonlinear diffusion equation, the phase field model has been established for ternary alloy spinodal decomposition, which directly couples with Calphad thermodynamics and dynamics calculation and takes into account the effect of the coherent elastic energy. The simulated microstructures of spinodal decomposition were carried out in the isothermally-aged of Cu-6at.%Ni-3at.%Si alloy. The results indicate that the spinodal decomposition takes place at the early stage of Cu-6at.%Ni-3at.%Si alloy aging at temperatures of 723K, forming two-phases mixture of Cu-rich and Ni/Si-rich, and the decomposition microstructures are distributed in a semi-interconnected labyrinth-like form. Under the effect of the coherent elastic energy, the decomposition microstructures demonstrate the obvious anisotropic characteristics, and present interconnected rectangular stripes aligned along [10] and [01] directions. The growth of the decomposition microstructures is in accordance with the growth law of growth exponentn≈0.29, slightly less than the LSW’s prediction.

scholarly journals Deep Learning Approach for Chemistry and Processing History Prediction from Materials Microstructure: Application to Spinodal Decomposition

2021 ◽  
Author(s):  
Amir Abbas Kazemzadeh Farizhandi ◽  
Omar Betancourt ◽  
Mahmood Mamivand
Keyword(s):  
Feature Extraction ◽  
Deep Learning ◽  
Chemical Composition ◽  
Spinodal Decomposition ◽  
Phase Field ◽  
Field Method ◽  
Phase Field Method ◽  
Processing Temperature ◽  
Learning Approach ◽  
Processing History

Abstract Finding the chemical composition and processing history from a microstructure morphology for heterogeneous materials is desired in many applications. While the simulation methods based on physical concepts such as the phase-field method can predict the spatio-temporal evolution of the materials’ microstructure, they are not efficient techniques for predicting processing and chemistry if a specific morphology is desired. In this study, we propose a framework based on a deep learning approach that enables us to predict the chemistry and processing history just by reading the morphological distribution of one element. As a case study, we used a dataset from spinodal decomposition simulation of Fe-Cr-Co alloy created by the phase-field method. The mixed dataset, which includes both images, i.e., the morphology of Fe distribution, and continuous data, i.e., the Fe minimum and maximum concentration in the microstructures, are used as input data, and the spinodal temperature and initial chemical composition are utilized as the output data to train the proposed deep neural network. The proposed convolutional layers were compared with pretrained EfficientNet convolutional layers as transfer learning in microstructure feature extraction. The results show that the trained shallow network is effective for chemistry prediction. However, accurate prediction of processing temperature requires more complex feature extraction from the morphology of the microstructure. We benchmarked the model predictive accuracy for real alloy systems with a Fe-Cr-Co transmission electron microscopy micrograph. The predicted chemistry and heat treatment temperature were in good agreement with the ground truth.

Phase field simulation of spinodal decomposition in Zr–Nb alloys for implant materials

2019 ◽  
Vol 126 (8) ◽  
pp. 085102
Author(s):  
Y. H. Wang ◽  
D. C. Zhang ◽  
Z. P. Pi ◽  
J. G. Lin ◽  
Cuie Wen
Keyword(s):  
Spinodal Decomposition ◽  
Phase Field ◽  
Phase Field Simulation ◽  
Implant Materials ◽  
Field Simulation
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