Search

In order to find more excellent structural materials resistant to radiation damage, high-entropy alloys (HEAs) have been developed due to their characteristics of limited point defect diffusion such as lattice distortion and slow diffusion. Specially, refractory high-entropy alloys (RHEAs) that can adapt to a high-temperature environment are badly needed. In this study, T i Z r H f N b M o 0.1 RHEAs are selected for irradiation and nanoindentation experiments. We combined the mechanistic model for the depth-dependent hardness of ion-irradiated metals and the introduction of the scale factor f to modify the irradiation-hardening model in order to better describe the nanoindentation indentation process in the irradiated layer. Finally, it can be found that, with the increase in irradiation dose, a more serious lattice distortion caused by a higher defect density limits the expansion of the plastic zone. [ABSTRACT FROM AUTHOR]

As a surface modification technique, chromization is often used in steels to improve their wear, corrosion, and oxidation resistances. High-entropy alloys (HEAs) with excellent properties can be applied in extreme environments, perhaps to further improve their resistance to external environments by chromization. In this work, the chromization of hot-rolled Fe 40 Mn 20 Cr 20 Ni 20 HEA was carried out by pack cementation. A chromized coating of 120 µm with the body-centered cubic (BCC) structure and a diffusion layer of 30 µm were obtained by chromizing at 1473 K for 12 h. Based on the growth kinetics of the coating, the relationship between the thickness of the chromized coating and chromized temperature as well as the time was modeled to visualize. After chromization, due to the higher chromium content of the coating, the Vickers hardness of was increased from 150 HV0.1 of hot-rolled HEA to more than 500 HV0.1, the wear rate was significantly reduced, and the dominant wear mechanisms for both hot-rolled and chromized HEAs under three test environments involved abrasion and adhesive wears. Besides, the corrosion resistance was promoted in NaCl solution (3.5 wt%). Thereby, the present work provides guidances for chromization on HEAs. [Display omitted] • The chromization of Fe 40 Mn 20 Cr 20 Ni 20 HEA is carried out by pack cementation. • Tribological behavior of chromized HEA under different environments is examined. • The relationship between the thickness of coating, temperature and time is modeled. [ABSTRACT FROM AUTHOR]

High-entropy amorphous FeCoCrNi thin-film catalysts with different Cr contents were prepared on the surface of copper substrate via electrodeposition. Their electrocatalytic performance for oxygen evolution reaction (OER) in alkaline solution was investigated. The catalyst with the optimal performance was obtained when the concentration of Cr3+ in the electrodeposition solution was 200 g/L. It achieved a current density of 10 mA⸱cm−2 with a low overpotential of merely 295 mV and demonstrated a Tafel slope of 69.52 mV⸱dec−1, indicating favorable reaction kinetics. Furthermore, this catalyst showed remarkable stability, maintaining its catalytic performance after 1000 cycles of cyclic voltammetry tests in the alkaline solution. The reasons for its excellent catalytic performance are as follows: (1) The uniform cracks and cellular structure on the film surface result in a larger active area; (2) The amorphous structure is more prone to surface reconstruction during the catalytic process, exposing more active sites; (3) Cr element regulates the valence states of Fe and Co ions as well as the existence forms of Ni and Co elements during the catalytic process, which accelerates the OER process and improves the catalytic performance. • The uniformly distributed cellular structure and cracks contribute to increasing the active surface area, exposing active sites. • The overpotential of the Cr-200 thin-film catalyst is 295 mV, and its Tafel slope is 69.52 mV⸱dec−1. • Compared to crystalline structures, the atomically disordered amorphous structure is more conducive to exposing active sites, which facilitates the progress of the oxygen evolution reaction. • The influence of Cr elements on the valence states and existence forms of other elements during the catalytic process has been investigated. [ABSTRACT FROM AUTHOR]