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Microstructural evolution and microsegregation in directional solidification of hypoeutectic Al−Cu alloy:A comparison between experimental data and numerical results obtained via phase-field model

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Transactions of Nonferrous Metals Society of China 2021年第7期31卷 1853-1867页

作者： Alexandre F.FERREIRA Ivaldo L.FERREIRA Rangel P.ALMEIDA Jose A.CASTRO Roberto C.SALES Zilmar A.JUNIOR Graduate Program on Metallurgical Engineering Federal Fluminense University27255-125Volta RedondaRJBrazil Federal University of Para College of Mechanical Engineering66075-110BelemPABrazil

The objective of the work is focused on predictions of microsegregation,solidification speed,dendritic arm spacings and dendrite morphology by phase-field *** numerical results were compared with experimental *** experimental values for cooling rates and effective partition coefficient were adopted during *** results of microsegregation through phase-field model show excellent agreement with the experimental *** excellent agreement is because cooling rates,effective partition coefficient and back-diffusion of solute are considered in the *** solidification speed,the calculation results show good agreement with the experimental *** dendritic arm spacing calculated with phase-field model is compared with experimental *** results show good agreement between *** dendrite arm spacing varies with position because high cooling rates are responsible for the refinement effect on ***,two-dimensional simulation produced a dendrite that is similar to that found in the experiment.

关键词： hypoeutectic Al−Cu alloy effective partition coefficient dendritic arm spacing microsegregation phase-field model

Comparative analysis of isothermal and non-isothermal solidification of binary alloys using phase-field model

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Transactions of Nonferrous Metals Society of China 2014年第11期24卷 3639-3644页

作者：肖荣振安国升朱昶胜王智平杨世银兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室兰州730050

Based on the entropy function, a two-dimensional phase field model of binary alloys was established. Meanwhile, an explicit difference method with uniform grid was adopted to solve the phase field and solute field controlled equations. And the alternating direction implicit(ADI) algorithm for solving temperature field controlled equation was also employed to avoid the restriction of time step. Some characteristics of the Ni-Cu alloy were captured in the process of non-isothermal solidification, and the comparative analysis of the isothermal and the non-isothermal solidification was investigated. The simulation results indicate that the non-isothermal model is favorable to simulate the real solidification process of binary alloys, and when the thermal diffusivity decreases, the non-isothermal phase-field model is gradually consistent with the isothermal phase-field model.

关键词： phase-field model binary alloys isothermal solidification non-isothermal solidification

Energy storage optimization of ferroelectric ceramics during phase-transition process of amorphous/nanocrystalline and polycrystalline by using a phaseffeld model for dielectric breakdown

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Journal of Advanced Dielectrics 2024年第1期14卷 33-41页

作者： Suilong Huang Jianwen Chen Zhen Su Xiucai Wang Wenbo Zhu Wenjun Chen Xinmei Yu Peng Xiao School of Electronic and Information Engineering Foshan University Foshan 528000P.R.China School of Mechatronic Engineering and Automation Foshan University Foshan 528000P.R.China China-Australia Institute for Advanced Materials and Manufacturing Jiaxing University Jiaxing 314001P.R.China School of Materials Science and Hydrogen Energy Foshan University Foshan 528000P.R.China School of Physics and Optoelectronic Engineering Foshan University Foshan 528000P.R.China

Ferroelectric ceramics have the potential to be widely applied in the modern industry and military power systems due to their ultrafast charging/discharging speed and high energy *** the structural design and electrical properties of ferroelectric capacitor,it is still a challenge to ffnd out the optimal energy storage of ferroelectric ceramics during the phase-transition process of amorphous/nanocrystalline and *** this work,a ffnite element model suitable for the multiphase ceramic system is constructed based on the phase ffeld breakdown *** nonlinear coupling relationship of multiple physical ffelds between multiphase ceramics was taken into account in this *** basic structures of multiphase ceramics are generated by using the Voronoi diagram construction *** speciffed structure of multiphase ceramics in the phase-transition process of amorphous/nanocrystalline and polycrystalline was further obtained through the grain boundary diffusion *** simulation results show that the multiphase ceramics have an optimal energy storage in the process of amorphous polycrystalline transformation,and the energy storage density reaches the maximum when the crystallinity is 13.96%and the volume fraction of grain is 2.08%.It provides a research plan and idea for revealing the correlation between microstructure and breakdown characteristics of multiphase *** simulation model realizes the nonlinear coupling of the multiphase ceramic mesoscopic structure and the phase ffeld *** provides a reference scheme for the structural design and performance optimization of ferroelectric ceramics.

关键词： Ferroelectric ceramics phase transition phase-field model dielectric breakdown energy storage

Growth and inhibition of zinc anode dendrites in Zn-air batteries:model and experiment

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Chinese Journal of Chemical Engineering 2024年第3期67卷 268-281页

作者： Cuiping He Qingyi Gou Yanqing Hou Jianguo Wang Xiang You Ni Yang Lin Tian Gang Xie Yuanliang Chen Kunming University of Science and Technology State Key Laboratory of Complex Nonferrous Metal Resources Clean UtilizationKunming 650093China Kunming University of Science and Technology Faculty of Metallurgical and Energy EngineeringKunming 650093China China Copper Co.Ltd KunmingYunnan 650051China State Key Laboratory of Advanced Metallurgy for Non-ferrous Metals Kunming 650051China Sichuan Shunying Power Battery Materials Co.Ltd Sichuan 620076China

Zinc(Zn)-air batteries are widely used in secondary battery research owing to their high theoretical energy density,good electrochemical reversibility,stable discharge performance,and low cost of the anode active material ***,the Zn anode also leads to many challenges,including dendrite growth,deformation,and hydrogen precipitation *** this context,Zn dendrite growth has a greater impact on the cycle *** this dissertation,a dendrite growth model for a Zn-air battery was established based on electrochemical phase field theory,and the effects of the charging time,anisotropy strength,and electrolyte temperature on the morphology and growth height of Zn dendrites were studied.A series of experiments was designed with different gradient influencing factors in subsequent experiments to verify the theoretical simulations,including elevated electrolyte temperatures,flowing electrolytes,and pulsed *** simulation results show that the growth of Zn dendrites is controlled mainly by diffusion and mass transfer processes,whereas the electrolyte temperature,flow rate,and interfacial energy anisotropy intensity are the main *** experimental results show that an optimal electrolyte temperature of 343.15 K,an optimal electrolyte flow rate of 40 ml·min^(-1),and an effective pulse charging mode.

关键词： Zn-air battery Zinc anode Zinc dendrite Simulated dendrite growth Inhibit dendrite growth phase-field model

phase-field Simulation of Sintering Process:A Review

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Computer modeling in Engineering & Sciences 2024年第8期140卷 1165-1204页

作者： Ming Xue Min Yi State Key Laboratory ofMechanics and Control forAerospace Structures&Institute for Frontier Science&Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education&College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics(NUAA)Nanjing210016China

Sintering,a well-established technique in powder metallurgy,plays a critical role in the processing of high melting point materials.A comprehensive understanding of structural changes during the sintering process is essential for effective product *** phase-field method stands out for its unique ability to simulate these structural *** its widespread application,there is a notable absence of literature reviews focused on its usage in sintering ***,this paper addresses this gap by reviewing the latest advancements in phase-field sintering models,covering approaches based on energy,grand potential,and entropy *** characteristics of various models are extensively discussed,with a specific emphasis on energy-based models incorporating considerations such as interface energy anisotropy,tensor-form diffusion mechanisms,and various forms of rigid particle motion during ***,the paper offers a concise summary of phase-field sintering models that integrate with other physical fields,including stress/strain fields,viscous flow,temperature field,and external electric *** conclusion,the paper provides a succinct overview of the entire content and delineates potential avenues for future research.

关键词： phase-field model review sintering additive manufacturing

phase-field modelling of spinodal decomposition with G-phase precipitation during ageing

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Science China(Technological Sciences) 2021年第12期64卷 2568-2576页

作者： SHI JiaQing SHEN Yao The State Key Lab of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China

The duplex stainless steels(DSSs)are susceptible to thermal ageing embrittlement due to the spinodal decomposition and Gphase precipitation in the ferritic *** study presents a ternary(Fe-Cr-Ni)phase-field model for the simulation of spinodal decomposition with concurrent G-phase *** Cahn-Hilliard equations and one Ginzburg-Landau equation are used in the model to describe the diffusion of Cr,Ni,and the growth of G-phase,*** model is able to generate a spinodally-interconnected structure with G-phase particles near theα-α′interfaces,similar to experimental *** kinetic synergy between spinodal decomposition and G-phase precipitation is *** simulation results indicate that Gphase can enhance the evolution of spinodal decomposition by occupying the volume where the decomposition could otherwise occur,and that the system’s elastic strain energy is largely contributed by G-phase rather than spinodal *** results would help in better understanding the states of the materials for plant structural integrity assessment and life management.

关键词： ferrite DSSs spinodal decomposition G-phase phase-field model

phase-field modeling of dendritic growth under forced flow based on adaptive finite element method

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Transactions of Nonferrous Metals Society of China 2015年第1期25卷 241-248页

作者：朱昶胜雷鹏肖荣振冯力兰州理工大学计算机与通信学院兰州730050 兰州理工大学有色金属先进加工与再利用国家重点实验室兰州730050

A mathematical model combined projection algorithm with phase-field method was applied. The adaptive finite element method was adopted to solve the model based on the non-uniform grid, and the behavior of dendritic growth was simulated from undercooled nickel melt under the forced flow. The simulation results show that the asymmetry behavior of the dendritic growth is caused by the forced flow. When the flow velocity is less than the critical value, the asymmetry of dendrite is little influenced by the forced flow. Once the flow velocity reaches or exceeds the critical value, the controlling factor of dendrite growth gradually changes from thermal diffusion to convection. With the increase of the flow velocity, the deflection angle towards upstream direction of the primary dendrite stem becomes larger. The effect of the dendrite growth on the flow field of the melt is apparent. With the increase of the dendrite size, the vortex is present in the downstream regions, and the vortex region is gradually enlarged. Dendrite tips appear to remelt. In addition, the adaptive finite element method can reduce CPU running time by one order of magnitude compared with uniform grid method, and the speed-up ratio is proportional to the size of computational domain.

关键词： dendritic growth phase-field model forced flow adaptive finite element method

phase-field modeling of faceted growth in solidification of alloys

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Chinese Physics B 2022年第4期31卷 706-709页

作者： Hui Xing Qi An Xianglei Dong Yongsheng Han The Key Laboratory of Space Applied Physics and Chemistry Northwestern Polytechnical UniversityXi’an 710029China College of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China The EMMS Group State Key Laboratory of Multiphase Complex SystemsInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China

A regularization of the surface tension anisotropic function used in vapor-liquid-solid nanowire growth was introduced into the quantitative phase-field model to simulate the faceted growth in solidification of *** results show that the value of δ can only affect the region near the tip,and the convergence with respect to δ can be achieved with the decrease of δ near the *** can be found that the steady growth velocity is not a mo no tonic function of the cusp amplitude,and the maximum value is approximately at ε=0.8 when the supersaturation is ***,the growth velocity is an increasing function of supersaturation with the morphological transition from facet to dendrite.

关键词： faceted growth dendrite phase-field model

phase-field modeling of Hydrogen Diffusion and Trapping in Steels

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Acta Metallurgica Sinica(English Letters) 2021年第10期34卷 1421-1426页

作者： Jun Zhang Jie Su Boning Zhang Yi Zong Zhigang Yang Chi Zhang Hao Chen Key Laboratory for Advanced Materials of Ministry of Education School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China China Iron and Steel Research Institute Beijing 100081China

Hydrogen embrittlement of steels is directly linked to hydrogen diffusion and trapping in the microstructure,which can hardly be precisely measured by modern experimental techniques.A phase-field model,in which a chemical potential well of hydrogen in the grain boundaries is introduced,is proposed to simulate hydrogen diffusion and trapping in the polycrystalline *** was interestingly found that grain boundaries,as connected trap sites,have a complex influence on the effective diffusivity of hydrogen,which are strongly linked to grain boundary diffusivity and binding energy.

关键词： Hydrogen embrittlement Diffusion Trapping Grain boundaries phase-field model