Rare Metals

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Microstructure and room temperature fracture toughness of Nb–Si-based alloys with Sr addition

  • Yong-Lin Huang
  • Li-Na JiaEmail author
  • Bin Kong
  • Yue-Ling Guo
  • Na Wang


Nb–Si-based alloys show great potential to surpass the widely used Ni-based superalloys. The element Sr is widely applied in aluminum and magnesium alloys, but reports about the effects of Sr on Nb–Si-based alloys are quite rare. So, Nb–Si-based alloys with nominal compositions of Nb–15Si–24Ti–4Cr–2Al–2Hf–0/0.05/0.15Sr (at%) were prepared by directional solidification and heat treatment. The microstructural characterization and room temperature fracture toughness of Nb–Si-based alloy were systematically investigated. Results show that all these alloys consist of Nb5Si3 phase embedded within Nb solid solution (Nbss) matrix. The Nb5Si3 phase becomes refined and more discontinuous after adding minor Sr. As for the fracture toughness, 0.05 at% and 0.15 at% Sr additions do not cause significant change. The discontinuous and refining mechanism of Sr element was studied, and the analysis of toughness decreasing with Sr addition reveals that the size of Nbss phase plays a crucial role in determining the fracture toughness.


Nb–Si alloy Refinement Discontinuous Fracture toughness Nbss 



This work was financially supported by the National Natural Science Foundation of China (Nos. 51471013, 51571004 and 51401017).


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© The Nonferrous Metals Society of China and Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.School of Materials Science and EngineeringBeihang UniversityBeijingChina

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