Phase-Field Simulation of δ-Ni2Si Precipitation in Cu-Ni-Si Alloys

2011 ◽  
Vol 689 ◽  
pp. 184-189
Author(s):  
Yong Qiang Long ◽  
Ping Liu ◽  
Yong Liu
Keyword(s):  
Phase Field ◽  
Interfacial Energy ◽  
Elastic Energy ◽  
Phase Field Model ◽  
Precipitation Process ◽  
Phase Precipitation ◽  
Coarsening Behavior ◽  
Δ Phase ◽  
Energy Anisotropy ◽  
Precipitation Phase

The phase-field model is established for precipitation transformations in multi-component alloy, which incorporates the interfacial energy and elastic energy anisotropy. The mechanism of the precipitation phase transition is revealed by means of the simulation of δ-phase precipitation process in Cu-4.0at.%Ni-2.0at.%Si alloy, and furthermore, the δ-phase precipitation kinetics is built at the temperature of 450°C. Under the influence of both interfacial energy and elastic energy anisotropy, δ-Ni2Si is presented in disc-shaped precipitates. The simulation patterns show that when one precipitate hits another precipitate with a different orientation, it stops growing, consequently forming a “T”-shape precipitate configuration. When two precipitates with the same orientations grow and hit each other, they connect or coarsen only if the spacing between the precipitates is very small. Therefore, the coarsening behavior of disc-shaped precipitate should be completely different from that of spherical precipitates.

The Simulation of Stress-Induced Phase Transition of L10 Re-Precipitation Based on Microscopic Phase-Field Model

2011 ◽  
Vol 689 ◽  
pp. 226-234
Author(s):  
Yong Xin Wang ◽  
Yong Biao Wang ◽  
Zheng Chen ◽  
Yan Li Lu
Keyword(s):  
Phase Transition ◽  
Induction Period ◽  
Phase Field ◽  
Field Model ◽  
Large Range ◽  
Phase Field Model ◽  
Precipitation Process ◽  
Phase Precipitation ◽  
Microscopic Phase Field Model ◽  
Precipitation Phase

It is common that the pre-precipitation phase with kinetics advantage is found during non-equilibrium transformation. The continuously changed stress in the transformation increases the complication of precipitation process. The stress induces Ll0pre-precipitation phase in Ni75-Al12.5-V12.5alloy is studied by microscope phase-field model in this paper. It is particularly show that Ll2phase precipitates directly without stress. There is no Ll0phase to be found in the disordered matrix. Oppositely, Ll0phase precipitates firstly with stress, and then it turns into Ll2phase. When stress is less, either or both above situations are observed. While stress is stronger, a large range of Ll0phase precipitates firstly. Then a part of it dissolves. The rest turns into Ll2phase. The precipitation of pre-precipitation phase accelerates the precipitation process. The larger the stress and the more Ll0phase precipitation, the longer it exists and the shorter the induction period is.

Interfacial Energy Anisotropy Affecting Dendrite Growth of Magnesium Alloy

2015 ◽  
Vol 1088 ◽  
pp. 238-241
Author(s):  
Xun Feng Yuan ◽  
Yan Yang
Keyword(s):  
Magnesium Alloy ◽  
Numerical Simulations ◽  
Phase Field ◽  
Interfacial Energy ◽  
Field Model ◽  
Phase Field Model ◽  
Dendrite Growth ◽  
Secondary Branch ◽  
Energy Anisotropy ◽  
Interfacial Energy Anisotropy

Numerical simulations based on a new regularized phase field model were presented, simulating the solidification of magnesium alloy. The effects of weak and strong interfacial energy anisotropy on the dendrite growth are studied. The results indicate that with weak interfacial energy anisotropy, the entire dendrite displays six-fold symmetry and no secondary branch appeared. Under strong interfacial energy anisotropy conditions, corners form on both the main stem and the tips of the side branches of the dendrites, the entire facet dendrite displays six-fold symmetry. As the solidification time increases, the tip temperature and velocity of the dendrite and facet dendrite finally tend to stable values. The stable velocity of the facet dendrite is 0.4 at ε6 is 0.05 and this velocity is twice that observed (0.2) at ε6 is 0.005.

Phase field model for strong interfacial energy anisotropy of HCP materials

2014 ◽  
Vol 24 (9) ◽  
pp. 2911-2919 ◽  
Author(s):  
Xun-feng YUAN ◽  
Bao-ying LIU ◽  
Chun LI ◽  
Chun-sheng ZHOU ◽  
Yu-tian DING
Keyword(s):  
Phase Field ◽  
Interfacial Energy ◽  
Field Model ◽  
Phase Field Model ◽  
Hcp Materials ◽  
Energy Anisotropy ◽  
Interfacial Energy Anisotropy

PHASE-FIELD MODELING OF ELASTIC EFFECTS IN EUTECTIC GROWTH WITH MISFIT STRESSES

2012 ◽  
Vol 04 (01) ◽  
pp. 1250024
Author(s):  
ZOHREH EBRAHIMI ◽  
JOAO REZENDEH
Keyword(s):  
Phase Field ◽  
Elastic Energy ◽  
Field Model ◽  
Phase Field Model ◽  
Solidification Process ◽  
Eutectic Growth ◽  
Point Of View ◽  
Eutectic Solidification ◽  
Elastic Model ◽  
Sharp Interface Model

Elastic interactions, arising from a difference of lattice spacing between two coherent phases in eutectic alloys with misfit stresses, can have an influence on microstructural pattern formation of eutectic colonies during solidification process. From a thermodynamic point of view the elastic energy contributes to the free energy of the phases and modifies their mutual stability. Therefore, the elastic stresses will have an effect on stability of lamellae, lamellae spacing and growth modes. In this paper, a phase-field model is employed to investigate the influence of elastic misfits in eutectic growth. The model reduces to the traditional sharp-interface model in a thin-interface limit, where the microscopic interface width is small but finite. An elastic model is designed, based on linear microelasticity theory, to incorporate the elastic energy in the phase-field model. Theoretical and numerical approaches, required to model elastic effects, are formulated and the stress distributions in eutectic solidification structures are evaluated. The two-dimensional simulations are performed for directed eutectic growth and the simulation results for different values of the misfit stresses are illustrated.

Phase-Field Simulation of Three-Dimensional Dendritic Growth

2010 ◽  
Vol 97-101 ◽  
pp. 3769-3772 ◽  
Author(s):  
Chang Sheng Zhu ◽  
Jun Wei Wang
Keyword(s):  
Computational Methods ◽  
Phase Field ◽  
Interfacial Energy ◽  
Dendritic Growth ◽  
Field Model ◽  
Three Dimensional ◽  
Phase Field Model ◽  
Computational Time ◽  
Field Simulation ◽  
Undercooled Melt

Based on a thin interface limit 3D phase-field model by coupled the anisotropy of interfacial energy and self-designed AADCR to improve on the computational methods for solving phase-field, 3D dendritic growth in pure undercooled melt is implemented successfully. The simulation authentically recreated the 3D dendritic morphological fromation, and receives the dendritic growth rule being consistent with crystallization mechanism. An example indicates that AADCR can decreased 70% computational time compared with not using algorithms for a 3D domain of size 300×300×300 grids, at the same time, the accelerated algorithms’ computed precision is higher and the redundancy is small, therefore, the accelerated method is really an effective method.

Computer Simulation of Evolution of Ordering Phases and the Boundaries of Ni-Cr-Al Alloy

2011 ◽  
Vol 233-235 ◽  
pp. 1782-1785
Author(s):  
Zhong Chu ◽  
Guo Qun Zhao
Keyword(s):  
Computer Simulation ◽  
Long Range ◽  
Phase Field ◽  
Field Model ◽  
Phase Field Model ◽  
Range Order ◽  
Precipitation Process ◽  
Al Alloy ◽  
Long Range Order

Based on the microscope phase-field model，the evolution of atom morphology, the long range order(lro) parameter and concentration can be gotten, and atomic clustering and ordering during the precipitation process of Ni-Cr-Al alloy could be obtained. The Ni-14at.%Cr-15.5at.%Al alloy is studied and the temperature of precipitation are 973K. It was showed that the ordering of both Al and Cr atoms take place simultaneously during the precipitation process of Ni-Al-Cr alloy, Cr atoms transfer to the boundaries of L12phases, the domain of rich Cr atoms are formed. At the boundaries of L12phases, Cr atoms may substitute the Al sublattice, and the D022phases are formed.

scholarly journals Eutectic colony formation in systems with interfacial energy anisotropy: A phase field study

2017 ◽  
Vol 130 ◽  
pp. 109-120 ◽  
Author(s):  
Arka Lahiri ◽  
Chandrashekhar Tiwary ◽  
Kamanio Chattopadhyay ◽  
Abhik Choudhury
Keyword(s):  
Field Study ◽  
Phase Field ◽  
Interfacial Energy ◽  
Colony Formation ◽  
Energy Anisotropy ◽  
Interfacial Energy Anisotropy ◽  
Eutectic Colony
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