Inclusion engineering in Co-based duplex entropic alloys

Wei Wang, Yong Wang, Wangzhong Mu, Joo Hyun Park, Hui Kong, Sohei Sukenaga, Hiroyuki Shibata, Henrik Larsson, Huahai Mao

Research output: Contribution to journalArticlepeer-review

Abstract

Co-based duplex entropic alloy is designed very recently to replace pure Co as a major component of the binder phase for cemented carbide cutting tools. This work aims to provide a fundamental study of oxide inclusion characteristics in the duplex fcc + hcp Co-based entropic alloys. It is found that the Co85−xCrxFe7.5Ni7.5 (x = 15, 30 at.%) alloys hold the highest liquidus (Tliq) and solidus (Tsol) temperatures, compare with the Co85−xCrxMn7.5Ni7.5 (x = 15, 30 at.%) and Co77.5−xCrxFe7.5Mn7.5Ni7.5 (x = 15, 30 at.%) alloys. For each grade, the increasing Cr content leads to a decrease of Tsol and Tliq temperatures. It is also noted that there is an approximate 100 °C of undercooling exists in each grade during the solidification. The stable oxide inclusion in the Co85−xCrxMn7.5Ni7.5 and Co77.5−xCrxFe7.5Mn7.5Ni7.5 alloys is the MnCr2O4 type, while Cr2O3 is the main stable inclusion in the Co85−xCrxFe7.5Ni7.5 alloy. Furthermore, the size range of the MnCr2O4 particles is larger than that of Cr2O3. The theoretical calculation shows that MnCr2O4 has a higher coagulation coefficient than Cr2O3 does. This is due to the influence of the thermo-physical parameters, i.e. the interfacial energy between the oxide and the alloy and the viscosity of liquid alloy. The theoretical calculation fits well with the experimental findings.

Original languageEnglish
Article number110097
JournalMaterials and Design
Volume210
DOIs
Publication statusPublished - 2021 Nov 15

Keywords

  • Agglomeration
  • Co-based alloys
  • Duplex entropic alloys
  • High temperature phase equilibria
  • Non-metallic inclusion

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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