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• The multilayers with ultra-thin amorphous layers exhibit the best radiation resistance. • The amorphous thickness can affect the interface structure during amorphous crystallization. • The hardness change is attributed to amorphous crystallization, dislocation nucleation-induced softening and radiation defects-induced hardening. Utilizing multilayer engineering to connect crystalline and amorphous can not only improve the mechanical properties but also enhance the radiation resistance of multilayers. However, the non-monotonic dependence of radiation resistance on the amorphous thickness necessitates an in-depth investigation into the size effect of the amorphous layer. Taking the Cu-Nb system as the prototype, we reveal the radiation resistance of Cu/Nb multilayers with varying thicknesses of the CuNb amorphous layer. After irradiation, multilayers with 0, 0.8, and 2 nm amorphous show flat or non-flat interface structures due to distinct crystalline growth processes during amorphous crystallization. Notably, multilayers with 0.8 nm amorphous exhibit the optimal radiation response, because the ultra-thin amorphous layer shows better thermal stability and slower crystallization rate that can annihilate more radiation defects and effectively inhibit defects growth. Furthermore, a quantitative analysis elucidates the reasons for hardness changes, which are attributed to amorphous crystallization, dislocation nucleation-induced softening, and radiation defects-induced hardening. [Display omitted] [ABSTRACT FROM AUTHOR]

Multi-principal element alloys (MPEAs) composed of thermally stable high-density cuboidal nanoparticles have revealed great potential for high-temperature applications. In this work, we systematically studied the growth behavior and coarsening kinetics of the cuboidal nanoparticles in Ni44Co22Cr22Al6Nb6MPEA. In the initial stage of isothermal aging, the nanoparticles exhibit growth and split behavior, resulting in the improvement of mechanical performance, then the cuboidal nanoparticles retain superior thermal and mechanical stability during long-term isothermal aging. The 288 kJ/mol activation energy of Ni44Co22Cr22Al6Nb6MPEA, which is higher than that in Ni-based superalloys, reveals the obvious elemental sluggish diffusion in Ni44Co22Cr22Al6Nb6MPEA. Meanwhile, coarsening rate constant determined by the volume diffusion mechanism in Ni44Co22Cr22Al6Nb6MPEA is 1–2 orders of magnitude less than that of the traditional Ni-based superalloys. The short-term regulation and long-term stability of the cuboidal nanoparticles endow the Ni44Co22Cr22Al6Nb6MPEA with superior mechanical performance and thermal stability for high temperature applications.

• Al addition can significantly affect impact toughness of BMGCs at 298 and 77 K. • Impact toughness of phase-tranformable BMGCs is sensitive to β-Ti phase stability. • Deformation-induced martenstic transformation of β-Ti is largely restricted at 77 K. • Cryogenic cyclic treatment affects toughness at 298 and 77 K in different ways. • Impact toughness is dominated by crystals at 298 K but by glass matrix at 77 K. Developing bulk metallic glass composites (BMGCs) with high toughness is vital for their practical application. However, the influence of different microstructures on the impact toughness of BMGCs is still unclear. The effects of Al addition and cryogenic cyclic treatment (CCT) on the Charpy impact toughness, a K , at 298 and 77 K of a series of phase-transformable BMGCs are investigated in this work. It is found that deformation-induced martensitic transformation (DIMT) of the β-Ti dendrites is the dominant toughening mechanism in the phase-transformable BMGCs at 298 K, but at 77 K, the toughness of BMGCs is primarily determined by the intrinsic toughness of the glass matrix. The addition of Al can moderately tune the β-Ti phase stability, which then affects the amount of DIMT and impact toughness of the BMGCs at 298 K. However, at 77 K, Al addition causes a monotonic decrease in the toughness of the BMGCs due to the embrittlement of the glass matrix. It is found that CCT can effectively rejuvenate the phase-transformable BMGCs, which results in an enhanced impact toughness at 298 K. However, the toughness at 77 K monotonously decreases with increasing the number of CCT cycles, suggesting that the rejuvenation of the glass matrix affects the toughness at both 298 and 77 K of BMGCs, but in dramatically different ways. These findings reveal the influence of microstructures and CCT on the impact toughness of BMGCs and provide insights that could be useful for designing tougher BMGs and BMGCs. [ABSTRACT FROM AUTHOR]

• The atomic scale irradiation response of AlCoCrFeNi 2.1 has been investigated. • The FCC phase has superior swelling tolerance than the B2 phase in AlCoCrFeNi 2.1. • The order-disorder transformation occurred in both FCC and B2 phases. • Compositional and lattice structural complexity dominate the radiation properties. Radiation-tolerant materials are widely desired in nuclear reactors. High-entropy alloys (HEAs) exhibiting superior mechanical performance and swelling tolerance are being considered as next-generation nuclear structural materials. However, an understanding of HEAs irradiation tolerance at an atomic scale is still lacking. In this study, the atomic scale irradiation response of AlCoCrFeNi 2.1 , composed of face-centered cubic (FCC) phase and B2 phase, has been systematically investigated at 298 and 723 K. The bubble volume ratio of the B2 phase is much larger than that of the FCC phase under the same irradiation conditions, and hence, the FCC phase has superior swelling tolerance than the B2 phase. Also, order-disorder transformation occurred in both L1 2 and B2 phases. The different irradiation responses between the FCC and B2 phases, depend firstly on composition and secondly on crystal structure. The higher compositional complexity and complicated atomic-level lattice environment of the FCC phase contribute to better radiation performance than B2 phase. The results pave a way for exploring radiation-tolerant structural high-entropy alloys. [Display omitted] [ABSTRACT FROM AUTHOR]

• Boron-doping induces grain refinement of TiZrNb from 96.0 μm to 16.2 μm. • The strength and ductility are increased by 19.0 % and 48.7 % after Boron-doping. • The deformation mechanism changes from planar to cross slip after Boron-doping. Body-centered cubic (BCC) multi-principal element alloys (MPEAs) have intrinsic high strength but poor ductility, which greatly limits their potential applications. Here we present the boron-doping strategy to enhance the strength and ductility of TiZrNb MPEAs simultaneously. The yield strength and ductility of the TiZrNb MPEA with boron addition of 500 ppm are increased by 19.0 % and 48.7 % compared to the boron-free TiZrNb MPEA, respectively. Boron-doping induced high efficiency in grain refinement from ∼96.0 μm to ∼16.2 μm is the main factor for strengthening. Dislocation dominated deformation mechanism involving cross slip and dislocation pining in the TiZrNb containing 500 ppm boron serves to enhance the strain-hardening capacity, resultant the enhancement of ductility from 7.8 % to 11.6 %. While the planar slip of dislocations is the dominated deformation mechanism for the boron-free TiZrNb. [ABSTRACT FROM AUTHOR]

Herein, nitrogen and sulfur codoped carbon dots (N&S CDs) were prepared by a facile hydrothermal process and they could be introduced as a fluorescent probe for the determination of cadmium ions (Cd2+), yielding high sensitivity and excellent selectivity. The obtained N&S CDs exhibited bright blue fluorescence with a quantum yield of 40% and exhibited a fast responsive fluorescence quenching signal within 2 min toward Cd2+in both ultrapure water and real water samples. The CDs responded to Cd2+, which acted as a quencher of blue fluorescence at 459 nm with the limit of detection of 0.018 μM in the range of 0.02–1 μM. The quenching fluorescence behavior was found to obey the static quenching effect (SQE). The low toxicity and good cell permeability of CDs were verified by cell experiments.

A comparative study of the extractive desulfurization (EDS) mechanism by Cu(II) and Zn-based ILs ([C4mim]2[MCl4], M = Cu(II) or Zn) has been performed. It is found that the π–π interaction and C-H⋯π interaction play important roles in EDS for both Cu(II) and Zn-based ILs, which is different from Al, Fe-based ILs. In the gas phase models, the interaction energy between Zn-based ILs and dibenzothiophene (DBT) is stronger than the interaction energy of Cu(II)-based ILs. In order to consider the solvent effect, a generic ionic liquid of solvation model has been implemented, which is few considered in the previous calculations of EDS. It is interesting to find that the gap of interaction energies between Cu(II), Zn-based ILs and DBT are reduced when the solvent effect is considered. In addition, by combined discussion of currently theoretical and experimental evidences for metal-based ILs with different compositions, we firstly propose that the EDS performance should be influenced by the balance of the contribution of cation, metal-based anion, metal chlorides and the viscosity.

Boron defect engineered boron nitride (BN) nanosheets have been prepared with the barbituric acid as co-reactant sources. By virtue of B defects, the electronic structure of BN undergo significantly variation, in which the conduction band of BN declined from −1.35 to −0.54 eV and decreased chemical acid hardness. After B defect engineering, BN nanosheets display greatly improved adsorptive desulfurization performance towards dibenzothiophene (DBT), with optimized adsorption capacity of 43.6 mgS g −1 for model oil. The increased adsorptive desulfurization performance was derived from decreased chemical acid hardness by B defect engineering, thus can build preferable interplay between the soft base DBT. [ABSTRACT FROM AUTHOR]