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NbHfTiVC0.1 refractory high-entropy alloy (RHEA) exhibits excellent comprehensive mechanical properties and demonstrates great potential for applications. However, the mechanical properties need to be improved further. In this work, hot rolling on NbHfTiVC0.1 RHEA at temperatures of 650 °C, 850 °C, and 1050 °C, with total reductions of up to 30%, 50%, 70%, and 80%, was conducted. The microstructure and mechanical property evolution of the samples were further investigated. The hot-rolled samples at 650 °C and 850 °C exhibit a composition consisting of BCC, carbide, and Laves phases, whereas the samples rolled at 1050 °C only consist of BCC and carbide phases. The 650-80 sample displays the highest ultimate tensile strength (1354 MPa), and the 1050-80 sample demonstrates the highest elongation (16%). The highest strength observed in the 650 °C-80% sample can be attributed to the presence of fractured and refined carbides, fine-grains, and the hindrance of dislocation slip by the fine Laves phase. At a higher rolling temperature (1050 °C), the Laves phase disappears, resulting in a reduction in strength but an increase in plasticity. Furthermore, the dislocation slipping mechanism within the BCC matrix also contributes positively to plastic deformation, leading to a notable increase in ductility for the 1050 °C-80% sample. These research findings provide valuable insights into enhancing the strength and ductility simultaneously of NbHfTiVC0.1 RHEA through hot rolling. [ABSTRACT FROM AUTHOR]

Eutectic high-entropy alloys (EHEAs) can achieve a balance of high strength and ductility. It has been found that the mechanical properties of hypoeutectic high-entropy alloys are superior to those of EHEAs. In this work, hypereutectic Al1.1CoCrFeNi2.1 alloy was prepared, and the mechanical properties in a wide temperature range were studied. The presence of both soft ordered L12 and hard BCC (B2) phases results in a combination of ductile and brittle fracture modes. The Al1.1CoCrFeNi2.1 hypereutectic high-entropy alloy contains more primary soft L12 phases, which ensure excellent ductility. Moreover, the Orowan by-passing mechanism caused by the B2 precipitates increases in the strength of the alloy for low-temperature tensile tests (−100 °C and 23 ± 2 °C). The −100 °C test exhibits a dimple morphology and demonstrates the highest ultimate tensile strength of 1231 MPa, along with an excellent elongation of 44%. At high tensile temperatures (650 °C, 750 °C, and 850 °C), the dislocation cutting mechanism and dynamic recrystallization increase the plasticity. However, the presence of a large number of cracks near the spherical primary L12 phase significantly reduces the ductility and strength. The results show that the hypereutectic Al1.1CoCrFeNi2.1 exhibits superior plasticity and strength properties at low temperatures. The findings of the article provide a new approach to enhancing the comprehensive mechanical properties of hypereutectic alloys. [ABSTRACT FROM AUTHOR]

Zr-Ti-Nb-Ta alloys were synthesized in parallel via multi-target co-sputtering deposition with physical masking in a pseudo-ternary Ti-Nb-ZrTa alloy system. Sixteen alloys with distinct compositions were obtained. Comprehensive characterization of phase structure, microstructure, Young's modulus, and nanoindentation hardness was undertaken. The Ti-Nb-ZrTa alloys exhibited two typical phase structures: a single-BCC solid-solution structure, and an amorphous structure. Nanoindentation quantification confirmed a Young's modulus ranging from 110 to 130 GPa, alongside nanoindentation hardness spanning 3.6 to 5.0 GPa. The combination of good hardness and a relatively low Young's modulus renders these alloys promising candidates for excellent biomedical materials. This work not only offers an effective method for the high-throughput synthesis of multi-principal element alloys, but also sheds light on a strategy for screening the phase structure and mechanical performance within a given alloy system. [ABSTRACT FROM AUTHOR]

In this work, SrCe0.9Yb0.1O3−δ powders were synthesized by a gel combustion method which combined gel process and combustion process. The effect of ratio of citric acid to metal cations (C/M), oxidizer and calcination temperature on the properties of powders was investigated in detail. It was found that the extra oxidizer NH4NO3 increased the flame temperature of combustion and thus promoted the formation of SrCeO3. The relative amount of SrCeO3 in powder increased as the C/M ratio increased. The as-ignited powder at 250 °C mainly consisted of the perovskite SrCeO3, i.e. relative amount of 95.2 wt%. The adiabatic flame temperature of the combustion reaction was calculated to be 1903.1 °C, higher than the required formation temperature of 787.2 °C for SrCeO3. Furthermore, the pure perovskite phase powder with agglomerated microstructure and average grain size of 2 μm was obtained after calcination at 1200 °C for 5 h. This heat-treatment temperature is 200 °C lower than the conventional solid state reaction method for SrCe0.9Yb0.1O3−δ preparation. [ABSTRACT FROM AUTHOR]

Designing biomimetic nanomaterials with peroxidase (POD)-like activity at neutral pH remains a significant challenge. An S-doping strategy is developed to afford an iron single-atom nanomaterial (Fe 1 @CN-S) with high POD-like activity under neutral conditions. To the best of knowledge, there is the first example on the achievement of excellent POD-like activity under neutral conditions by regulating the active site structure. S-doping not only promotes the dissociation of the N─H bond in 3,3″,5,5″-tetramethylbenzidine (TMB), but also facilitates the desorption of OH* by the transformation of iron species' spin states from middle-spin (MS Fe II ) to low-spin (LS Fe II ). Meanwhile, LS Fe II sites typically have more unfilled d orbitals, thereby exhibiting stronger interactions with H 2 O 2 than MS Fe II , which can enhance POD-like activity. Finally, a one-pot visual detection of glucose at pH 7 is performed, demonstrating the best selectivity and sensitivity than previous reports., (© 2024 Wiley‐VCH GmbH.)