Senary refractory high-entropy alloy Cr_xMoNbTaVW

Journal Article · 10 November 2015 · Calphad

DOI: https://doi.org/10.1016/j.calphad.2015.09.007 · OSTI ID:1482329

Zhang, B. ^[1]; Gao, M. C. ^[2]; Zhang, Y. ^[1]; Guo, S. M. ^[1]

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1. Louisiana State Univ., Baton Rouge, LA (United States)
2. National Energy Technology Lab. (NETL), Albany, OR (United States); AECOM, Albany, OR (United States)

This paper demonstrates that a senary refractory high-entropy alloy Cr_xMoNbTaVW can be tailored over a certain range of Cr content with the BCC structure for different microstructures and physical properties, assisted by CALPHAD simulations. Microstructure characterizations are performed using X-ray diffraction and scanning electron microscopy. Chemical microsegregation during solidification predicted using the Scheil model generally agrees with the experimental results. The lattice constant, density, and Vickers’ micro-hardness of the highentropy alloy samples in the as-cast state are measured and discussed. For Cr_xMoNbTaVW, x=2.0 case appears exceeding the upper limit of maintaining a single BCC phase HEA, determined by the XRD patterns. The elemental dependence of the mixing thermodynamic properties (entropy, enthalpy and Gibbs energy) in BCC phase in the senary system is analyzed. The calculated entropy of mixing and enthalpy of mixing for CrMoNbTaVW are 14.7 J/K/mol and -662.5 J/mol respectively.

• Research Organization: National Energy Technology Lab. (NETL), Albany, OR (United States)
• Sponsoring Organization: USDOE; USDOE Office of Fossil Energy (FE)
• Grant/Contract Number: FE0004000; FE0004734; FE0007220; FE0008382; FE0011550
• OSTI ID: 1482329
• Journal Information: Calphad, Journal Name: Calphad Journal Issue: C Vol. 51; ISSN 0364-5916
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English