Effect of Mo on the Mechanical and Corrosion Behaviors in Non-Equal Molar AlCrFeMnNi BCC High-Entropy Alloys

Wei-Chen Hsu,Che-Wei Tsai,Jien-Wei Yeh,Wei-Pin Kao

doi:10.3390/ma15030751

Wei-Chen Hsu, Che-Wei Tsai + Show 2 more

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https://doi.org/10.3390/ma15030751

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Journal: Materials	Publication Date: Jan 19, 2022
Citations: 8	License type: CC BY 4.0

Affiliation: National Tsing Hua University

Abstract

Co-free body-centered cubic (bcc) high-entropy alloys (HEAs) are prepared, and the elevated mechanical property and corrosion property of the Al0.4CrFe1.5MnNi0.5Mox (x = 0 and 0.1) alloys are studied. The Vickers hardness (HV) of the as-homogenized state is between HV 350 and HV 400. Both alloys are provided with nano-scale NiAl-rich B2 precipitates which contribute to the strength at high-temperature. In addition, adding Mo in the present alloy strengthens by σ phase. Al0.4CrFe1.5MnNi0.5Mo0.1 exhibited outstanding tensile properties, with a yield strength of 413 MPa and ultimate tensile strength of 430 MPa in the elevated tensile test at 600 °C, which is better than that of Al0.4CrFe1.5MnNi0.5 alloy. Through potentiodynamic polarization testing in 0.5 M H2SO4 solution and electrochemical impedance spectroscopy (EIS), it is shown that adding Mo can effectively reduce the corrosion current density and improve the impedance of passive film, since the passivation layer is formed and stable.

Highlights

In 2004, a new alloy design concept called high-entropy alloys (HEAs) was proposed by Yeh et al [1,2,3,4]
Most research focuses on single-phase FCC alloys, such as CoCrFeMnNi [31,32] and CoCrFeNi [33,34], as well as BCC refractory alloys
To the authors’ knowledge, the non-refractory BCC HEAs have been relatively overlooked from the mechanical point of view

Summary

Introduction

In 2004, a new alloy design concept called high-entropy alloys (HEAs) was proposed by Yeh et al [1,2,3,4]. In recent years, it has been used in various research topics, including ceramics [5,6], polymers [7], and composites [8]. The idea of mixing multiple elements while increasing configurational entropy (>1.5 R) to enhance high-temperature phase stability expands the potential of new alloy design. To the authors’ knowledge, the non-refractory BCC HEAs have been relatively overlooked from the mechanical point of view

Methods

Discussion

Conclusion