首页|Superconductivity and hardness of the equiatomic high-entropy alloy HfMoNbTiZr

Superconductivity and hardness of the equiatomic high-entropy alloy HfMoNbTiZr

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? 2022 Elsevier B.V.We have found that body-centered cubic (bcc) HfMoNbTiZr is a type-II BCS high-entropy alloy (HEA) superconductor with a superconducting critical temperature of Tc = 4.1 K. By employing a Debye temperature θD of 263 K and Tc, the electron-phonon coupling constant λe-p is calculated to be 0.63. The electronic structure calculation revealed band broadening with energy uncertainties due to atomic disorders. The superconducting properties are compared among equiatomic quinary bcc HEA superconductors. Tc decreases with decreasing λe-p, which is negatively correlated with θD. The negative correlation between λe-p and θD would be caused by a shorter phonon lifetime at a higher θD, which is based on phonon broadening due to atomic disorder and the uncertainty principle. The Vickers microhardness was measured for several bcc HEA superconductors. Tc is exceptionally low in a superconductor with relatively high hardness, because the hardness generally increases with increasing θD, and θD is negatively correlated with Tc in the high-entropy state.

Electron-phonon couplingHardnessHigh-entropy alloysSuperconductivity

Kawasaki Y.、Nishizaki T.、Kitagawa J.、Koga R.、Hoshi K.、Mizuguchi Y.

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Department of Electrical Engineering Faculty of Science and Engineering Kyushu Sangyo University

Department of Electrical Engineering Faculty of Engineering Fukuoka Institute of Technology

Department of Physics Tokyo Metropolitan University

2022

Journal of Alloys and Compounds

Journal of Alloys and Compounds

EISCI
ISSN:0925-8388
年,卷(期):2022.924
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