In the past decade, the emergence of high-entropy alloys (HEAs) and other high-entropy materials (HEMs) has brought about new opportunities in the development of novel materials for high-performance applications. In combining solid-solution (SS) strengthening with grain-boundary strengthening, new material systems—nanostructured or nanocrystalline (NC) HEAs or HEMs—have been developed, showing superior combined mechanical and functional properties compared with conventional alloys, HEAs, and NC metals. This article reviews the processing methods, materials, mechanical properties, thermal stability, and functional properties of various nanostructured HEMs, particularly NC HEAs. With such new nanostructures and alloy compositions, many interesting phenomena and properties of such NC HEAs have been unveiled, for example, extraordinary microstructural and mechanical thermal stability. As more HEAs or HEMs are being developed, a new avenue of research is to be exploited. The article concludes with perspectives about future directions in this field.

The breakdown of the columnar grains and lamellar α + β colony microstructure in two-phase Ti alloys during conversion of ingot to billet is critical to the development of desired combination of mechanical properties. Colony breakdown occurs during a series of thermomechanical processing steps in the α + β phase field. However, fundamental knowledge of the microstructural dependence of this transformation is limited, particularly its dependence on the initial orientation of the α + β colony relative to the imposed strain-path. In this study, the viscoplastic self-consistent polycrystal plasticity model is used to examine deformation behavior as a function of crystal loading direction. Criteria were developed to predict relative globularization rates; it was found that both slip system activities in the α phase and relative crystal rotations of each phase must be considered. Predictions are demonstrated to be consistent with literature and suggest that further experimental investigation of relative globularization rates is necessary.

Contact guidance is vital to many physiological processes, yet is still poorly understood. This is partly due to the variability of experimental platforms, making comparisons difficult. To combat this, a multiplexed approach was used to fabricate topographical cues on single quartz coverslips for high-throughput screening. Furthermore, this method offers control of surface roughness and protein adsorption characterization, two critical aspects to the in vitro environment often overlooked in contact guidance platforms. The quartz surface can be regenerated, is compatible with versatile microscopy modes, and can scale up for manufacturing offering a novel platform that could serve as a potential standard assay.

Graphene enticed the scientific community for its interesting properties since its discovery. Among different synthesis routes of graphene, reduction of graphene oxide (GO) is mostly preferred because of scalability and advantage of modulation of properties of the end product. Thermal reduction of GO is considered to be the simplest and economic among different reduction techniques. The current work reports an experimental analysis of the structural evolution of GO to reduced graphene oxide (rGO) during thermal treatment. GO has been thermally annealed at an optimized temperature of 350 °C in ambient. Thermal reduction is observed after 7 min of annealing and confirmed by shifting of the first major peak from 12° to 23° in X-ray diffraction pattern. Significant carbon content enrichment and exfoliation are two aspects of the thermal reduction of GO. Carbon content suddenly enriches from 38 wt% in GO to 77 wt%. Exfoliation is confirmed by morphological alterations and decrease in carbon layers from eleven to three.

Pancreatic cancer is currently one of the most lethal tumors because of delayed diagnosis and treatment. Aminopeptidase N (CD13/APN), expressed in pancreatic cancer cells, is closely related to the malignant biological behavior, for instance, angiogenesis formation, tumor proliferation, and metastasis. In this study, asparagine–glycine–arginine (Asn–Gly–Arg, NGR), selectively binding to CD13 receptor, was modified to construct a novel contrast agent of QDs@Gd3+-NGR for targeted diagnosis and treatment of pancreatic cancer. It consists of QDs-unit for fluorescence imaging, Gd3+-unit for magnetic resonance imaging (MRI), and NGR for binding to CD13 receptor. PANC-1 cells labeled by QDs@Gd3+-NGR showed significant red fluorescence and high intensity on fluorescence and MR imaging, respectively. Besides, it was confirmed that QDs@Gd3+-NGR could inhibit theproliferation, metastasis, and invasion of PANC-1 cells, and increase reactive oxygen species production and death rate in vitro. Reasonably, we believe the targeted contrast agent of QDs@Gd3+-NGR can sensitively detect pancreatic cancer via MR-fluorescence dual-modality imaging, and plays an active role in inhibition of tumor progression. The promising results in this study provide integration of diagnostic and therapeutic strategy for the management of pancreatic cancer in future.

In this study, mechanical properties and microstructural investigation of Ti64 at high strain rate are studied using a split-Hopkinson pressure bar method under compression for temperatures up to 800 °C. Flow softening in the mechanical response of material to such loading conditions hints at instability in compression, which increases with an increase in temperature. Microstructural characterization of the deformed material is characterized using the electron-backscattered diffraction technique. It reveals the presence of instabilities in Ti64 in the form of a fine network of shear bands. The shear band width grows with an increase in temperature along with the area fraction of shear band in the material, displaying its improved capacity to contain microstructural instabilities at higher temperature. After a detailed microstructural investigation, a mechanism for shear band widening is proposed. Based on this mechanism, a path generating nuclei within shear bands is discussed.

The authors demonstrate that multicomponent metallic alloy nanofoams can be synthesized by the polymeric templating method. The present approach enabled alloy compositions not accessible via commonly used dealloying or co-deposition methods. The authors report the synthesis of a Cu50Ni50 alloy nanofoam using electrospinning polymeric templating, which exhibits distinct polycrystallinity, process-driven segregation, and enhanced mechanical strength over pure Cu nanofoams. Transmission electron microscopy revealed microscopic grain formation and their variable compositions. The processing method is applicable to the synthesis of a wide range of multicomponent metal porous materials, creating new research opportunities for noble alloy foams not available through wet electrochemical routes.

Traditional dip-assisted layer-by-layer (LbL) assembly produces robust and conformal coatings, but it is time-consuming. Alternatively, spray-assisted layer-by-layer (SA-LbL) assembly has gained interest due to rapid processing resulting from the short adsorption time. However, it is challenging to assemble anisotropic nanomaterials using this spray-based approach. This is because the standard approach for fabricating “all-polyelectrolyte” LbL films does not necessarily give rise to satisfactory film growth when one of the adsorbing components is anisotropic. Here, polymers are combined with a model anisotropic nanomaterial via SA-LbL assembly. Specifically, graphene oxide (GO) is investigated, and the effect of anchor layer, colloidal stability, charge distribution along the carbon framework, and concentration of polymer on the growth and the film quality is examined to gain insight into how to achieve pinhole-free, smooth polymer/GO SA-LbL coatings. This approach might be applicable to other anisotropic nanomaterials such as clays or 2D nanomaterials for future development of uniform coatings by spraying.

Chiral magnets in the B20 crystal structure host a peculiar spin texture in the form of a topologically stable skyrmion lattice. However, the helical transition temperature (TC) of these compounds is below room temperature, which limits their potential in spintronics applications. Here, a data-driven approach is demonstrated, which integrates density functional theory (DFT) calculations with machine learning (ML) in search of alloying elements that will enhance the TC of known B20 compounds. Initial DFT screening led to the identification of chromium (Cr) and tin (Sn) as potential substituents for alloy design. Then, trained ML models predict Sn substitution to be more promising than Cr-substitution for tuning the TC of FeGe. The magnetic exchange energy calculated from DFT validates the promise of Sn as an effective alloying element for enhancing the TC in Fe(Ge,Sn) compounds. New B20 chiral magnets are recommended for experimental investigation.

The computational tool integrating empirical tight binding and full configuration interaction method is utilized to study the structural and optical properties of spherical PbX (X = S, Se, and Te) nanocrystals under various diameters. The nanocrystal architecture plays an essential role in the control of the structural and optical properties. The appearance of the quantum confinement is caused by the reduction of the optical band gaps with the increasing diameters. By changing the chalcogenide types and diameters, the band gaps are modified, with their wavelengths from 380 to 2500 nm, technologically applying for the visible and near-infrared optical devices. The tight-binding band gaps agree well with previously published theoretical and experimental values. The atomistic electron–hole interactions are mainly influenced by the diameters and chalcogenide types. Using the Stokes shift and fine structure splitting, PbS nanocrystal with the immense size may be implemented as a source of entangled photon pairs and optical filter. Finally, the theoretical study reveals the distinctive properties of PbX (X = S, Se, and Te) nanocrystals by changing their architecture for applications in optoelectronic devices and microscopy.