Competitive Growth of Degenerate Pattern and Dendrites During Directional Solidification of a Bicrystal Metallic Alloy

  • Yumin Wang
  • Shuangming LiEmail author
  • Zhenpeng Liu
  • Bin Yang
  • Hong Zhong
  • Hui Xing


A degenerate pattern is seaweed-like morphology with its tip splitting continuously, differing from that the regular dendrite has a stable tip. Here, we carried out bicrystal (BC)-assembled experiments to investigate the competitive growth between a degenerate pattern and regular dendrites in a directionally solidified Al-4.5 wt pct Cu alloy. Using the electron backscattered diffraction (EBSD) technique, we characterized a degenerate pattern that solidified with a (100)[001]45 deg orientation and a dendrite growth comprising (100)[001]0 deg or (100)[001]15 deg orientations. The experimental results for the competitive growth show that the dendrites could overgrow the degenerate pattern completely at V = 15 and 25 µm/s. The grain boundary (GB) in between these two morphologies is not smooth, and its inclination angle θGB is slightly increased with an increase in the growth velocity. For the converging GBs, we find that the dendrites overgrow the degenerate pattern either by generating new primary arm dendrites through tertiary branching or being blocked by the growth of the existing primary arm dendrites, depending on the misorientation arrangement between these two morphologies. The limited growth stability of the degenerate pattern in comparison with the dendrite contributes to deepening the understanding of why the degenerate pattern is not widely prevailing in metallic alloy solidification microstructures.



This research is financially supported by the National Natural Science Foundation of China (No. 51474174), Research Funds of the State Key Laboratory of Solidification Processing in NWPU (No. 2019-TS-01). Yumin Wang thanks Ming Ma from Electronic Materials Research Laboratory of Xian Jiaotong University for his help on RO-XRD tests


  1. 1.
    1. A. Pineau, G. Guillemot, D. Tourret, A. Karma, and C.A. Gandin: Acta Mater., 2018, vol. 155, pp. 286-301.CrossRefGoogle Scholar
  2. 2.
    2. S.S. Hu, L. Liu, W.C. Yang, J. Zhang, T.W. Huang, Y.C. Wang, and X.D. Zhou: J. Alloy. Compd., 2018, vol. 735, pp. 1878-84.CrossRefGoogle Scholar
  3. 3.
    3. Z.Y. Liu, M. Lin, D. Yu, X.W. Zhou, Y.X. Gu, and H.Z. Fu: Metall. Mater. Trans. A-Phys. Metall. Mater. Sci., 2013, vol. 44A, pp. 5113-21.CrossRefGoogle Scholar
  4. 4.
    4. A.J. Clarke, D. Tourret, Y. Song, S.D. Imhoff, P.J. Gibbs, J.W. Gibbs, K. Fezzaa, and A. Karma: Acta Mater., 2017, vol. 129, pp. 203-16.CrossRefGoogle Scholar
  5. 5.
    Y. Song, S. Akamatsu, S. Bottin-Rousseau, and A. Karma: Phys. Rev. Mater., 2018, vol. 2, p. 053403.CrossRefGoogle Scholar
  6. 6.
    6. D. Walton, and B. Chalmers: Trans. Metall. Soc. AIME, 1959, vol. 215, pp. 447-57.Google Scholar
  7. 7.
    7. M. Rappaz, and C.A. Gandin: Acta Metall. Mater., 1993, vol. 41, pp. 345-60.CrossRefGoogle Scholar
  8. 8.
    8. S. Akamatsu, G. Faivre, and T. Ihle: Phys. Rev. E, 1995, vol. 51, pp. 4751-73.CrossRefGoogle Scholar
  9. 9.
    9. Y.M. Wang, S.M. Li, Z.P. Liu, H. Zhong, L. Xu, and H. Xing: J. Mater. Sci. Technol., 2019, vol. 35, pp. 1309-14.CrossRefGoogle Scholar
  10. 10.
    B. Utter, and E. Bodenschatz: Phys. Rev. E, 2005, vol. 72, p. 011601.CrossRefGoogle Scholar
  11. 11.
    11. Y. Chen, B. Billia, D.Z. Li, H. Nguyen-Thi, N.M. Xiao, and A.A. Bogno: Acta Mater., 2014, vol. 66, pp. 219-31.CrossRefGoogle Scholar
  12. 12.
    12. N. D’Souza, M.G. Ardakani, A. Wagner, B.A. Shollock, and M. McLean: J. Mater. Sci., 2002, vol. 37, pp. 481-87.CrossRefGoogle Scholar
  13. 13.
    13. Y.Z. Zhou, A. Volek, and N.R. Green: Acta Mater., 2008, vol. 56, pp. 2631-37.CrossRefGoogle Scholar
  14. 14.
    14. H.L. Yu, J.J. Li, X. Lin, L.L. Wang, and W.D. Huang: J. Cryst. Growth, 2014, vol. 402, pp. 210-14.CrossRefGoogle Scholar
  15. 15.
    15. S.S. Hu, W.C. Yang, Q.W. Cui, T.W. Huang, J. Zhang, and L. Liu: Mater. Charact., 2017, vol. 125, pp. 152-59.CrossRefGoogle Scholar
  16. 16.
    16. J. Eiken: Int. J. Cast. Metals Res., 2009, vol. 22, pp. 86-89.CrossRefGoogle Scholar
  17. 17.
    17. J.J. Li, Z.J. Wang, Y.Q. Wang, and J.C. Wang: Acta Mater., 2012, vol. 60, pp. 1478-93.CrossRefGoogle Scholar
  18. 18.
    18. C.W. Guo, J.J. Li, H.L. Yu, Z.J. Wang, X. Lin, and J.C. Wang: Acta Mater., 2017, vol. 136, pp. 148-63.CrossRefGoogle Scholar
  19. 19.
    19. T. Takaki, M. Ohno, Y. Shibuta, S. Sakane, T. Shimokawabe, and T. Aoki: J. Cryst. Growth, 2016, vol. 442, pp. 14-24.CrossRefGoogle Scholar
  20. 20.
    20. T. Takaki, M. Ohno, T. Shimokawabe, and T. Aoki: Acta Mater., 2014, vol. 81, pp. 272-83.CrossRefGoogle Scholar
  21. 21.
    21. D. Tourret, Y. Song, A.J. Clarke, and A. Karma: Acta Mater., 2017, vol. 122, pp. 220-35.CrossRefGoogle Scholar
  22. 22.
    F. Li, L. Jin, Z. Xu, and Z.Q. Guo: Rev. Sci. Instrum., 2009, vol. 80, p. 085106.CrossRefGoogle Scholar
  23. 23.
    23. L.Y. Yang, S.M. Li, Y. Li, K. Fan, and H. Zhong: J. Mater. Res., 2019, vol. 34, pp. 240-50.CrossRefGoogle Scholar
  24. 24.
    H. Xing, X.L. Dong, H.J. Wu, G.H. Hao, J.Y. Wang, C.L. Chen, and K.X. Jin: Sci Rep, 2016, vol. 6, p. 26625.CrossRefGoogle Scholar

Copyright information

© The Minerals, Metals & Materials Society and ASM International 2019

Authors and Affiliations

  • Yumin Wang
    • 1
  • Shuangming Li
    • 1
    Email author
  • Zhenpeng Liu
    • 1
  • Bin Yang
    • 1
  • Hong Zhong
    • 1
  • Hui Xing
    • 2
  1. 1.State Key Laboratory of Solidification ProcessingNorthwestern Polytechnical University, ShaanxiXi’anPeople’s Republic of China
  2. 2.MOE Key Laboratory of Material Physics and Chemistry under ExtraordinaryNorthwestern Polytechnical UniversityXi’anPeople’s Republic of China

Personalised recommendations