Eutectic high-entropy alloys (EHEAs) have drawn increasing interest due to their fine castability as well as appealing properties in recent years. In this work, two bulk-casting Co_20-x/3Cr_20-x/3Ni_50-x/3Al_10+x (x = 8 and 9) EHEAs with regular L1₂/B2 lamellar morphologies were successfully fabricated and studied. Both EHEAs show high ultimate strength of ~1200 MPa combined with good uniform ductility (> 9%). Post-deformation transmission electron microscopy results indicated a high density of dislocations and stacking faults in the L1₂ lamellae, while no obvious dislocation in the B2 phases. This work can broaden the optimization of composition design in EHEAs and provide useful guidance for further development of CoCrNiAl EHEAs.

The lattice arrangement and degree of buckling have been playing vital roles in the structure stability, bonding configuration, and electronic band structures of two-dimensional (2D) single-layer materials. Here, we fabricate two tin allotropes beyond honeycomb stanene by epitaxial growth method on Al(111). Sn-I phase with quasi-periodic lattice and Sn-II phase with square-like lattice have been identified by scanning tunneling microscopy. Combined with scanning tunneling spectroscopy, it is revealed that Sn-II phase with four-coordinate tin atoms exhibits enhanced decoupling effects due to their saturated bonds. In this study, the discovery of new lattice arrangements with well-defined atomic structures beyond honeycomb lattice provides an appealing approach to searching 2D elemental single layers and novel physical properties.

A series of [(FeNiCo)_0.85Cr_0.15]_100-xB_x (x = 12, 15, 17) high-entropy alloys with network-like microstructures (N-HEAs) and a wavelength of 3-5 μm was prepared using the fluxing method. The novel N-HEAs exhibited higher strength and ductility compared with samples obtained by suction casting. Neutron diffraction and scanning electron microscopy measurements showed that the network-like structure contained soft face-centered cubic (FCC) and hard tetragonal Cr₂B-type sub-networks. The network-like structure was formed during the solidification of the molten alloy from a deeply undercooled state, achieved by removing impurities and most metallic oxides through B₂O₃ fluxing. The mechanical properties could be tuned by modifying the composition to change the volume fractions of the different sub-networks. When x decreased from 17 to 12, the compressive yield strength decreased from 1.6 to 1.1 GPa, while the compressive strain increased from ~20% to ~70%. The N-HEA samples with x = 12 and 15 also exhibited a good tensile ductility of 19% and 14%, respectively. In situ synchrotron X-ray diffraction results revealed an inhomogeneous deformation behavior, i.e., the soft FCC phase yielded prior to the hard Cr₂B-type phase, which bore more stress in the initial stage of the plastic deformation. In the later stage of the plastic deformation, the ductility of the sample was provided by the FCC phase, together with some contributions from the Cr₂B-type phase.

Carbon nanotubes (CNTs) have a one-dimensional (1D) hollow tubular structure formed by graphene curling with remarkable electronic, optical, mechanical, and thermal properties. Except for the applications based on their intrinsic properties, such as electronic devices, THz sensors, and conductive fiber, CNTs can also act as nano-vessels for nano-chemical reactions and hosts for encapsulating various materials to form heterostructures. In this review, we have summarized the research status on filled carbon-nanotube heterostructures from four aspects: synthesis, morphological and electronic structure analysis, potential applications, and perspective. We begin with an overview of the filling methods and mechanisms of the 1D heterostructures. Following that, we discuss their properties in terms of morphological and electronic structure. The burgeoning applications of 1D heterostructures in nano-electronic, energy, storage, catalysis, and other fields are then thoroughly overviewed. Finally, we offer a brief perspective on the possible opportunities and challenges of filled CNTs heterostructures.

Duplex stainless steel is widely used in the petrochemical, maritime, and food industries. However, duplex stainless steel has the problem of corrosion failures during use. This topic has not been comprehensively and academically reviewed. These factors motivate the authors to review the developments in the corrosion research of duplex stainless steel. The review found that the primary reasons for the failure of duplex stainless steels are pitting corrosion and chloride-induced stress corrosion cracking. After being submerged in water, the evolution of the passive film on the duplex stainless steel can be loosely classified into three stages: nucleation, rapid growth, and stable growth stages. Instead of dramatic rupture, the passive film rupture process is a continuous metal oxidation process. Environmental factors scarcely affect the double-layer structure of the passive film, but they affect the film's overall thickness, oxide ratio, and defect concentration. The six mechanisms of alloying elements on pitting corrosion are summarized as stabilization, ineffective, soluble precipitates, soluble inclusions, insoluble inclusions, and wrapping mechanisms. In environments containing chlorides, ferrite undergoes pitting corrosion more easily than austenite. However, the pitting corrosion resistance reverses when sufficiently large deformation is used. The mechanisms of pitting corrosion induced by precipitates include the Cr-depletion, microgalvanic, and high-stress field theories. Chloride-induced cracks always initiate in the corrosion pits and blunt when encountering austenite. Phase boundaries are both strong hydrogen traps and rapid hydrogen diffusion pathways during hydrogen-induced stress cracking.

A large driving pressure is required for barocaloric effects (BCEs) in intermetallics, usually above 100 MPa. Here, we report barocaloric effects in Mn_3-xPt_1+xalloys saturated at about 60 MPa, the lowest pressure reported in intermetallics to date. A first-order phase transition occurs from the colinear antiferromagnetic phase to the triangular antiferromagnetic phase as temperature decreases. The transition temperature strongly depends on the composition x, ranging from 331 K for x = 0.18 to 384 K for x = 0.04, and is sensitive to pressure, with dT_t/dP up to 139 K/GPa. However, the maximum pressure-induced entropy changes are as small as 13.79 J kg^-1 K^-1, attributed to the mutual cancellation of lattice and magnetic entropy changes. The small driving pressure and total entropy changes are due to the special magnetic geometric frustration.

Ceramics with high-energy storage density are in high demand across various industries. In this regard, lead-free relaxor ferroelectric ceramics were synthesized using the conventional solid-state reaction method with the composition (1-x)[0.94Bi_0.5Na_0.5TiO₃-0.06BaTiO₃]-xSr_0.8Biγ_0.1Ti_0.8Zr_0.2O_0.95, abbreviated as BNBT-xSBTZ. The incorporation of SBTZ in BNBT ceramics significantly improved their relaxation properties. Specifically, the 0.91BNBT-0.09SBTZ ceramics displayed a breakdown electric field of up to 230 kV/cm, with a recoverable energy storage density (W_r) of 2.68 J/cm³ and an energy storage efficiency (η) of 74.4%. Additionally, this sample demonstrated remarkable temperature stability and fatigue resistance, with only an 11% decrease in W_r observed from room temperature to 140 °C and a 13.3% reduction in W_r after 10⁵ electrical cycles. Therefore, the 0.91BNBT-0.09SBTZ ceramic is a promising dielectric material suitable for energy-storage dielectric capacitors.

Photocatalytic reduction of carbon dioxide (CO₂) is a promising technology for carbon recycling that offers both environmental and economic benefits. Among the potential photocatalysts, metal nanoclusters (MNCs) stand out as a class of materials with remarkable photophysical and photochemical properties. Despite the growing number of studies on MNCs-based photocatalytic reduction of CO₂ in recent years, a systematic and comparative overview of these studies is still lacking. This review provides a concise and comprehensive summary of the latest research on MNCs-based catalysts for enhancing photocatalytic CO₂ reduction performance. Moreover, this review highlights the challenges and opportunities in this field based on the current development trends.

The practical application of carbon-supported Pt-based catalysts for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs) still faces many limitations, including carbon corrosion and their weak interaction with Pt-based nanoparticles (NPs). Harnessing the strong metal-support interaction (SMSI) effects at the interface between Pt-based nanoparticles and alternative corrosion-resistant non-carbon support is an effective strategy to address these issues. The rational design of Pt-based catalysts with favorable SMSI and elucidation of the mechanisms underlying such interactions is indispensable for achieving desirable activity and stability. In this review, first, the basic principles of the ORR are briefly introduced. Next, the formation process of SMSI, construction strategies, and the advantages and drawbacks of representative supports, including transition metal oxides, nitrides, and carbides (TMOs, TMCs, and TMNs, respectively), are fully discussed. Finally, the challenges and prospects in promoting the practical applications of the SMSI effect for ORR are highlighted.

We investigate flux-grown BiFeO₃ crystals using transmission electron microscopy (TEM). This material has an intriguing ferroelectric structure of domain walls with a period of approximately 100 nm, alternating between flat and sawtooth morphologies. We show that all domain walls are of 180° type and that the flat walls, lying on (112) planes, are reconstructed with an excess of Fe and a deficiency of Bi. This reconstruction is similar to that observed in several previous studies of deposited layers of BiFeO₃. The negative charge of the reconstructed layer induces head-to-head polarisation in the surrounding material and a rigid-body shift of one domain relative to the other. These characteristics pin the flat 180° domain walls and determine the domain structure of the material. Sawtooth 180° domain walls provide the necessary reversal of polarisation between flat walls. The high density of immobile domain walls suppresses the ferroelectric properties of the material, highlighting the need for careful control of growth conditions.