Enhancement of glass-forming ability and thermal stability of a soft magnetic Co75B25 metallic glass by micro-alloying Y and Nb

Feng Bao, Yan hui Li, Zheng wang Zhu, Xin yu Liang, Yan Zhang, Wei Zhang

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Soft magnetic Co-based Co–Y–Nb–B bulk metallic glasses (BMGs) without Fe have been developed by micro-alloying Y and Nb into a Co75B25 alloy. First, addition of 3–4 at.% Y promotes the occurrence of glass transition and increases the supercooled liquid stability and magnetic softness. Co71.5Y3.5B25 metallic glass possesses a large supercooled liquid region (ΔTx) of 33 K and low coercivity (Hc) of 1.5 A/m. Subsequent alloying 2–4 at.% Nb into Co71.5Y3.5B25 alloy further enlarges ΔTx to 50 K, lowers Hc to 0.9 A/m, and enables the formation of BMGs with a critical sample diameter up to 2.0 mm. The alloying Nb causes the formation of complex (Co, Nb, Y)23B6 competing phase during crystallization and widens the melt undercooling during solidification, which improves the supercooled liquid stability and glass-forming ability, respectively. Co–Y–Nb–B BMGs also exhibit good soft magnetic and mechanical properties, i.e., low Hc of 0.9–1.2 A/m, relatively high saturation magnetic flux density of 0.36–0.57 T, high yielding strength of 3877–3930 MPa with plastic strain of 0.2%–0.3%, and high Vickers hardness of 1156–1201. The developed soft magnetic Co-based BMGs are promising for applications as structural and functional materials.

Original languageEnglish
JournalJournal of Iron and Steel Research International
Publication statusAccepted/In press - 2020


  • Co-based bulk metallic glass
  • Glass-forming ability
  • Micro-alloying
  • Soft magnetic property
  • Thermal stability

ASJC Scopus subject areas

  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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