J. Mater. Sci. Technol. ›› 2021, Vol. 94: 104-112.DOI: 10.1016/j.jmst.2021.02.065

• Research Article • Previous Articles     Next Articles

Enhanced grain refinement of Al-Si alloys by novel Al-V-B refiners

Chenxi Zhaoa,1, Yang Lia,1, Jin Xub, Qun Luoa, Ying Jiangb, Qiling Xiaob, Qian Lia,b,*()   

  1. aState Key Laboratory of Advanced Special Steels, Shanghai Key Laboratory of Advanced Ferrometallurgy, School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China
    bMaterials Genome Institute, Shanghai University, Shanghai 200444, China
  • Received:2020-12-27 Revised:2021-02-11 Accepted:2021-02-21 Published:2021-12-20 Online:2021-05-18
  • Contact: Qian Li
  • About author:*State Key Laboratory of Advanced Special Steels, Shanghai Key Laboratory of Advanced Ferrometallurgy, School of Materials Science and Engineering, Shanghai University, Shanghai 2004 4 4,China. E-mail address: shuliqian@shu.edu.cn (Q. Li).
    First author contact:

    1These authors contributed equally to this work.

Abstract:

Al-V-B master alloy is promising for refining Al-Si alloys, yet its optimal composition with superior efficacy remains to be explored. In this work, the evolution of refining phases in the Al-10Si/Al-V-B system with different V:B ratios was evaluated by thermodynamic calculations, based on which the Al-V-B refiners with V:B = 1:1 and 5:1 were designed. Refining trails demonstrated that they could significantly reduce the grain size of Al-10Si (wt.%) alloy from 1736 to 184-245 μm with industrial addition amount. Detailed examinations results clarify that when V:B ratio is 1:1 the nucleation particle is (V,Al)B2, which has a VB2-AlB2 core-shell structure and therefore presents the nucleation capability as AlB2 particle. When V:B ratio is as high as 5:1, the nucleation particle is pure VB2. Density functional theory (DFT) calculation indicates that (0 0 0 1) VB2/(1 1 1) α-Al interface has the lowest interfacial energy such that highest nucleation potency among other types of diboride/α-Al interfaces under consideration. The outcomes of this work provide fundamental guidance to develop superior V-B based refiners for Al-Si alloys.

Key words: Al-Si alloys, Grain refinement, Al-V-B, Interfacial structure, Thermodynamic calculation