Solid-Solid Phase Transformations in Aluminium Alloys Described by a Multiphase-Field Model

2006 ◽  
Vol 508 ◽  
pp. 579-584 ◽  
Author(s):  
Igor Kovačević ◽  
Božidar Šarler
Keyword(s):  
Phase Transformations ◽  
Aluminium Alloys ◽  
Field Model ◽  
Driving Forces ◽  
Solid Phase ◽  
Solute Diffusion ◽  
Aluminium Matrix ◽  
Field Equations ◽  
Integrated Concept ◽  
Using Data

A model for solving isothermal solid-solid phase transformations in multicomponent aluminium alloys is presented. A multiphase-field model for the dissolutions of various phases in an aluminium matrix during homogenization is presented. Driving forces for phase transformations are calculated using data obtained from the commercial software JMatPro and an aluminium database. An integrated concept of the multiphase-field model with solute diffusion is used. A onedimensional model for the simultaneous dissolution of the Mg2Si and Si phases in the aluminium matrix of ternary Al-Mg-Si alloys is introduced. An explicit central finite difference numerical scheme is used for the solution of the time transient phase-field equations and the solute diffusion equations.

Multiphase Phase-Field Approach for Virtual Melting: A Brief Review

2021 ◽  
Vol 18 (2) ◽  
pp. 102-107
Author(s):  
Arunabha Mohan Roy
Keyword(s):  
Phase Transformations ◽  
Phase Field ◽  
Field Model ◽  
Solid Phase ◽  
Scale Effects ◽  
Phase Field Model ◽  
Short Review ◽  
Nanoscale Material ◽  
Material Parameters ◽  
Field Approach

A short review on a thermodynamically consistent multiphase phase-field approach for virtual melting has been presented. The important outcomes of solid-solid phase transformations via intermediate melt have been discussed for HMX crystal. It is found out that two nanoscale material parameters and solid-melt barrier term in the phase-field model significantly affect the mechanism of PTs, induces nontrivial scale effects, and changes PTs behaviors at the nanoscale during virtual melting.

The multiphase-field model with an integrated concept for modelling solute diffusion

1998 ◽  
Vol 115 (1-2) ◽  
pp. 73-86 ◽  
Author(s):  
J. Tiaden ◽  
B. Nestler ◽  
H.J. Diepers ◽  
I. Steinbach
Keyword(s):  
Field Model ◽  
Solute Diffusion ◽  
Integrated Concept

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.

Solute redistribution during in-situ irradiation of alloys in the high voltage electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 370-371
Author(s):  
P. R. Okamoto ◽  
N.Q. Lam ◽  
R. L. Lyles
Keyword(s):  
Electron Microscope ◽  
High Voltage ◽  
Driving Forces ◽  
Solute Diffusion ◽  
Solute Redistribution ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
High Voltage Electron ◽  
Thin Foils ◽  
Solute Atoms

During irradiation of thin foils in a high voltage electron microscope (HVEM) defect gradients will be set up between the foil surfaces and interior. In alloys defect gradients provide additional driving forces for solute diffusion since any preferential binding and/or exchange between solute atoms and mobile defects will couple a net flux of solute atoms to the defect fluxes. Thus, during irradiation large nonequilibrium compositional gradients can be produced near the foil surfaces in initially homogeneous alloys. A system of coupled reaction-rate and diffusion equations describing the build up of mobile defects and solute redistribution in thin foils and in a semi-infinite medium under charged-particle irradiation has been formulated. Spatially uniform and nonuniform damage production rates have been used to model solute segregation under electron and ion irradiation conditions.An example calculation showing the time evolution of the solute concentration in a 2000 Å thick foil during electron irradiation is shown in Fig. 1.

Heat capacities and enthalpies of fusion and transformation for solvates of some salts with dimethyl sulfoxide and dimethylformamide

1988 ◽  
Vol 53 (12) ◽  
pp. 3072-3079
Author(s):  
Mojmír Skokánek ◽  
Ivo Sláma
Keyword(s):  
Heat Capacity ◽  
Phase Transformation ◽  
Phase Transformations ◽  
Dimethyl Sulfoxide ◽  
Liquidus Temperature ◽  
Molar Heat Capacity ◽  
Solid Phase ◽  
Zinc Nitrate ◽  
Heat Capacities ◽  
Liquid Phases

Molar heat capacities and molar enthalpies of fusion of the solvates Zn(NO3)2 . 2·24 DMSO, Zn(NO3)2 . 8·11 DMSO, Zn(NO3)2 . 6 DMSO, NaNO3 . 2·85 DMSO, and AgNO3 . DMF, where DMSO is dimethyl sulfoxide and DMF is dimethylformamide, have been determined over the temperature range 240 to 400 K. Endothermic peaks found for the zinc nitrate solvates below the liquidus temperature have been ascribed to solid phase transformations. The molar enthalpies of the solid phase transformations are close to 5 kJ mol-1 for all zinc nitrate solvates investigated. The dependence of the molar heat capacity on the temperature outside the phase transformation region can be described by a linear equation for both the solid and liquid phases.

Reactivity in solid phase. Transformations of 2,4-di-tert-butylphenol and its derivatives under elastic deformation conditions

1996 ◽  
Vol 45 (6) ◽  
pp. 1428-1432
Author(s):  
V. B. Vol'eva ◽  
I. S. Belostotskaya ◽  
A. Yu. Karmilov ◽  
N. L. Komissaroya ◽  
V. V. Ershov
Keyword(s):  
Phase Transformations ◽  
Elastic Deformation ◽  
Solid Phase

scholarly journals A mathematical approach to Ostwald ripening due to diffusion and deformation in liquid bridge

2013 ◽  
Vol 45 (3) ◽  
pp. 261-271 ◽  
Author(s):  
B. Randjelovic ◽  
K. Shinagawa ◽  
Z.S. Nikolic
Keyword(s):  
Liquid Phase ◽  
Liquid Bridge ◽  
Ostwald Ripening ◽  
Solid Phase ◽  
Liquid Phase Sintering ◽  
Solute Diffusion ◽  
Deformation Analysis ◽  
Mathematical Approach ◽  
Fe Method ◽  
Grain Coarsening

From many experiments with mixtures of small and large grains, it can be concluded that during liquid phase sintering, smaller grains partially dissolve and a solid phase precipitates on the larger grains and grain coarsening occurs. The growth rate can be controlled either by the solid-liquid phase boundary reaction or by diffusion through the liquid phase. The microstructure may change either by larger grains growing during the Ostwald ripening process or by shape accommodation. In this study, two-dimensional mathematical approach for simulation of grain coarsening by grain boundary migration based on a physical and corresponding numerical modeling of liquid phase sintering will be considered. A combined mathematical method of analyzing viscous deformation and solute diffusion in liquid bridge between two grains with different sizes will be proposed. The viscous FE method will be used for calculating meniscus of the liquid bridge, with the interfacial tensions taken into consideration. The FE method for diffusion will be also implemented by using the same mesh as the deformation analysis.

The growth kinetics of individual ledges during solid-solid phase transformations

1981 ◽  
Vol 378 (1774) ◽  
pp. 351-368 ◽  
Keyword(s):  
Phase Transformations ◽  
Volume Diffusion ◽  
Solid Phase ◽  
Parent Phase ◽  
Steady Motion ◽  
Diffusion Field ◽  
Lateral Growth ◽  
Small Perturbations ◽  
Step Motion ◽  
Kinetics Of

The problem of step motion during lateral growth in solid-solid phase transformations is re-examined. Results are obtained for the steady motion of an individual ledge when volume diffusion in the parent phase is the predominant contribution to the growth rate. A comparison is made between our results and the earlier work of Jones & Trivedi (1971). There are significant differences between the two sets of results particularly in the limit of small perturbations to the Laplacian diffusion field. To confirm the accuracy of the results presented here the calculations have been made by two different methods.

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