Inclusion engineering in Co-based duplex entropic alloys

Autor: Wei Wang, Yong Wang, Wangzhong Mu, Joo Hyun Park, Hui Kong, Sohei Sukenaga, Hiroyuki Shibata, Henrik Larsson, Huahai Mao
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Materials & Design, Vol 210, Iss , Pp 110097- (2021)
Druh dokumentu: article
ISSN: 0264-1275
DOI: 10.1016/j.matdes.2021.110097
Popis: 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.
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