Journal of Materials Science

, Volume 54, Issue 7, pp 5844–5851 | Cite as

Effect of Si additions on microstructure and mechanical properties of refractory NbTaWMo high-entropy alloys

  • Zhiming Guo
  • Aijun Zhang
  • Jiesheng Han
  • Juhu MengEmail author


To improve the high-temperature strength and decrease the density of NbTaWMo alloys, addition of light element Si producing the second-phase silicide is employed. Refractory NbTaWMoSix (x = 0, 0.25, 0.5, 0.75) high-entropy alloys are produced by spark plasma sintering. The phase evolution, microstructure, compressive mechanical properties, and high-temperature hardness are investigated in this study. It reveals that there is only a disordered body-centered cubic (BCC) phase in the matrix NbTaWMo alloy. After adding the Si element, NbTaWMoSix alloys demonstrate the presence of multiphase structure: disordered BCC phase and silicide phase. As the content of Si is increased, the proportion of silicide is increased, which improves the hardness and strength. The addition of Si at certain concentration (x = 0.25 and 0.5) has positive effect on ductility of the alloys. The alloys all demonstrate brittle fracture due to the brittle phase of BCC and silicide phase. The high-temperature hardness of NbTaWMoSix alloys is increased with the addition of Si, but the same alloy presents a slightly decreasing phenomenon as the temperature improves.



This work was funded by a grant from Major Programs of the Chinese Academy of Sciences during the 13th Five-Year Plan Period.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


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Authors and Affiliations

  1. 1.State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhouPeople’s Republic of China
  2. 2.University of Chinese Academy of SciencesBeijingPeople’s Republic of China

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