中国物理B ›› 2020, Vol. 29 ›› Issue (7): 78104-078104.doi: 10.1088/1674-1056/ab8abb

• INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY • 上一篇    下一篇

Modeling of microporosity formation and hydrogen concentration evolution during solidification of an Al-Si alloy

Qingyu Zhang(张庆宇), Dongke Sun(孙东科), Shunhu Zhang(章顺虎), Hui Wang(王辉), Mingfang Zhu(朱鸣芳)   

  1. 1 Shagang School of Iron and Steel, Soochow University, Suzhou 215137, China;
    2 Jiangsu Key Laboratory for Advanced Metallic Materials, School of Materials Science and Engineering, Southeast University, Nanjing 211189, China;
    3 Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering, Southeast University, Nanjing 211189, China;
    4 State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China
  • 收稿日期:2019-12-23 修回日期:2020-03-04 出版日期:2020-07-05 发布日期:2020-07-05
  • 通讯作者: Qingyu Zhang, Mingfang Zhu E-mail:qingyu.zhang@suda.edu.cn;zhumf@seu.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 51901148), the Fund of the State Key Laboratory of Solidification Processing (Northwestern Polytechnical University), China (Grant No. SKLSP202006), and the State Key Lab of Advanced Metals and Materials (University of Science and Technology Beijing), China (Grant No. 2019-Z15).

Modeling of microporosity formation and hydrogen concentration evolution during solidification of an Al-Si alloy

Qingyu Zhang(张庆宇)1,2, Dongke Sun(孙东科)3, Shunhu Zhang(章顺虎)1, Hui Wang(王辉)4, Mingfang Zhu(朱鸣芳)2   

  1. 1 Shagang School of Iron and Steel, Soochow University, Suzhou 215137, China;
    2 Jiangsu Key Laboratory for Advanced Metallic Materials, School of Materials Science and Engineering, Southeast University, Nanjing 211189, China;
    3 Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering, Southeast University, Nanjing 211189, China;
    4 State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China
  • Received:2019-12-23 Revised:2020-03-04 Online:2020-07-05 Published:2020-07-05
  • Contact: Qingyu Zhang, Mingfang Zhu E-mail:qingyu.zhang@suda.edu.cn;zhumf@seu.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 51901148), the Fund of the State Key Laboratory of Solidification Processing (Northwestern Polytechnical University), China (Grant No. SKLSP202006), and the State Key Lab of Advanced Metals and Materials (University of Science and Technology Beijing), China (Grant No. 2019-Z15).

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摘要： We simulate the evolution of hydrogen concentration and gas pore formation as equiaxed dendrites grow during solidification of a hypoeutectic aluminum-silicon (Al-Si) alloy. The applied lattice Boltzmann-cellular automaton-finite difference model incorporates the physical mechanisms of solute and hydrogen partitioning on the solid/liquid interface, as well as the transports of solute and hydrogen. After the quantitative validation by the simulation of capillary intrusion, the model is utilized to investigate the growth of the equiaxed dendrites and hydrogen porosity formation for an Al-(5 wt.%)Si alloy under different solidification conditions. The simulation data reveal that the gas pores favorably nucleate in the corners surrounded by the nearby dendrite arms. Then, the gas pores grow in a competitive mode. With the cooling rate increasing, the competition among different growing gas pores is found to be hindered, which accordingly increases the pore number density in the final solidification microstructure. In the late solidification stage, even though the solid fraction is increasing, the mean concentration of hydrogen in the residue melt tends to be constant, corresponding to a dynamic equilibrium state of hydrogen concentration in liquid. As the cooling rate increases or the initial hydrogen concentration decreases, the temperature of gas pore nucleation, the porosity fraction, and the mean porosity size decrease, whilst the mean hydrogen concentration in liquid increases in the late solidification stage. The simulated data present identical trends with the experimental results reported in literature.

关键词: microporosity, solidification microstructure, modeling, lattice Boltzmann method

Abstract: We simulate the evolution of hydrogen concentration and gas pore formation as equiaxed dendrites grow during solidification of a hypoeutectic aluminum-silicon (Al-Si) alloy. The applied lattice Boltzmann-cellular automaton-finite difference model incorporates the physical mechanisms of solute and hydrogen partitioning on the solid/liquid interface, as well as the transports of solute and hydrogen. After the quantitative validation by the simulation of capillary intrusion, the model is utilized to investigate the growth of the equiaxed dendrites and hydrogen porosity formation for an Al-(5 wt.%)Si alloy under different solidification conditions. The simulation data reveal that the gas pores favorably nucleate in the corners surrounded by the nearby dendrite arms. Then, the gas pores grow in a competitive mode. With the cooling rate increasing, the competition among different growing gas pores is found to be hindered, which accordingly increases the pore number density in the final solidification microstructure. In the late solidification stage, even though the solid fraction is increasing, the mean concentration of hydrogen in the residue melt tends to be constant, corresponding to a dynamic equilibrium state of hydrogen concentration in liquid. As the cooling rate increases or the initial hydrogen concentration decreases, the temperature of gas pore nucleation, the porosity fraction, and the mean porosity size decrease, whilst the mean hydrogen concentration in liquid increases in the late solidification stage. The simulated data present identical trends with the experimental results reported in literature.

Key words: microporosity, solidification microstructure, modeling, lattice Boltzmann method

中图分类号:  (Metals, semimetals, and alloys)

  • 81.05.Bx
81.30.-t (Phase diagrams and microstructures developed by solidification and solid-solid phase transformations) 47.55.D- (Drops and bubbles) 47.61.Jd (Multiphase flows)