Two-dimensional (2D) semiconductor devices hold great promise in specialized operating regimes including radio-frequency, high-temperature, and cryogenic conditionsu2014yet their potential for power handling has received little emphasis, so far. Here we report a molybdenum disulphide (MoS2) device design that strategically selects the channel width (W) and length (L) to distribute current density and mitigate self-heating, enabling operation at a source-drain bias Vds of 10 V and a drain current Ids of 0.1 A, while maintaining an on/off ratio of 105. This corresponds to sustained dissipation P = IdsVds ~ 1 W, and highlights a pathway for Watt-level switching in van der Waals electronics. We demonstrate a sensor circuit that uses our Watt-level MoS2 transistors to function as a step-down converter and a switching device. Further, a proof-of-concept on flexible substrates is presented. Our findings mark a step change in 2D power electronics, paving the way for higher-voltage devices compatible with flexible substrates and, ultimately, wearable and conformal power systems.

Refractory high-entropy alloys (RHEAs) show considerable promise for high-temperature structural applications. However, the poor room-temperature ductility severely limits their practical engineering applications. Here, we demonstrate nanoscale B2 chemical-order domain (COD) tuning strategy that enables Al-Ti-Zr-Nb refractory high-entropy superalloy to achieve uniform tensile plasticity of 20.1% and yield strength of 1,010 MPa. A high density of CODs effectively hinders dislocation motion, and triggers a unique dislocation multiplication driven by double cross-slip. These multiplied dislocations advance into the planar slip bands, forming entanglements with pre-existing dislocations. This enhances the glide resistance for subsequent dislocations, forcing them to transition onto higher-order slip planes via cross-slip. Notably, the fission of the planar slip bands halts the original slip plane softening process. Furthermore, cross-slip-induced dislocations interact with those on adjacent slip planes, initiating chain reactions. This dislocation activity, akin to a cascade of falling dominoes, propagates plastic deformation into underformed regions, thereby mitigating stress concentration. This strategy provides a viable ductilization strategy for RHEAs, facilitating their deployment in structural applications.

Reactive high-entropy alloys (RHEAs), have attracted considerable interest for defense and energy applications owing to their superior mechanical properties and significant chemical energy release potential. These materials often operate under extreme dynamic loading conditions, making it essential to understand their deformation mechanisms under shock loading. This study investigates the shock-induced deformation of high-strength TiZrHfNb RHEA via light gas gun based plate-impact experiments at strain rates of similar to 10(5) s(-1) and shock pressures of 5-10 GPa. With increasing shock pressure, the alloy undergoes sequential martensitic transitions: an orthorhombic alpha '' phase forms below 8 GPa, while a reversible, expansive body-centered tetragonal beta ' phase emerges at 9.45 GPa, characterized by elongation along < 001 > and a < c. These stepwise, diffusionless transitions represent a rapid structural adaptation to dissipate mechanical energy under shock loading, providing key insights for RHEA applications in hypervelocity impact and explosive forming.

Shear banding is widely regarded as a precursor to dynamic failure of solids, yet what drives its emergence remains elusive. Here, we precisely capture the onset of shear bands in the most typical Cantor CoCrFeMnNi high-entropy alloy via the unique single-pulse Hopkinson torsion bar-based deformation-freezing hybridizing synchronized temperature measurement technique. It is surprisingly found that shear bands emerge well before the stress-strain curve peak and exhibit a distinctive nanoscale morphology, in sharp contrast to traditional consensus. Precise microstructural characterization reveals that these bands originate from discrete stacking faults, where atomic-scale dilatation at their tips reduces shear deformation resistance and triggers configurational softening. To disentangle and quantify the competing effect between thermal softening and configurational softening, we develop a non-equilibrium two-temperature continuum plastic flow model. Stability analysis establishes the nanoscale shear band instability criterion and demonstrates that configurational softening, rather than widely accepted adiabatic thermal softening, governs their emergence. These findings shed new insights into understanding shear banding and dynamic failure behaviors in metals.

Strength and plasticity are critical properties but always unavoidable trade-offs of materials for various service environment. The vast composition-property space of refractory high entropy alloy (RHEAs) enables resolving this trade-off, but makes their composition design highly challenging. Herein, we formulate a physical feature-guided design strategy for RHEAs toward balanced strength-plasticity across strain rates. Three RHEAs with a superior combination of strength and plasticity over wide strain rate ranges were discovered and synthetized. The composition-property diagrams are constructed and an optimal composition range is identified based on model prediction for several typical refractory elements. By decoding the key physical features governing property trade-offs via interpretable machine learning (ML), this study establishes a data-efficient paradigm for multi-objective materials design, demonstrated here for refractory high-entropy alloys but extensible to other complex systems.

As a new type of energetic structural materials, reactive high entropy alloys (RHEAs) feature an excellent combination of kinetic and chemical energy damage capability, and have become increasingly crucial in aerospace, energy, and defense fields. However, the hypervelocity impact damage mechanism of this new reactive alloy remains elusive due to its intrinsic strong coupling of rate-dependent mechanical, thermal, and chemical processes. Here, based on a hydrogen-oxygen detonation driving two-stage light gas gun platform hybridizing with laser shadow method and high-speed photography technique, we designed a set of experiments to explore hypervelocity impact behavior of TiZr-based reactive high entropy alloy, 6061-Al and SS 304 projectiles on double-layered plates. It was observed that the debris cloud of RHEA projectile underwent additional expansion under the influence of chemical reactions compared with the other two inert alloy projectiles. The additional expansion of the debris cloud, coupled with the energy released from chemical reactions, leads to a broader distribution and larger number of perforations in the rear plate, and more notably, causes significantly intensified structural damage. Through synthesizing experimental results and theoretical analysis, we demonstrate that the damage enhancement mechanism of this RHEA projectile is primarily governed by three dimensionless numbers: the Damkohler number, the generalized Euler number, and the reaction damage number, which respectively characterize the extent of chemical reactions, the expansion behavior of the debris cloud, and the chemical energy-induced damage to the rear plate. Our findings provide a fundamental understanding of RHEA projectile hypervelocity impact double-layer plate.

Refractory high-entropy superalloys (RHESs) have emerged as promising materials to meet the demands for high-temperature structural applications. Nevertheless, they encounter inevitable room-temperature brittleness. In this study, the brittle deformation mechanisms under different loading modes are explored. The sheared BCC + B2 superstructure is observed beneath the nanoindentation, indicating that plastic deformation induced by dislocation movement. Dislocations repeatedly slip on the same slip plane, resulting in a relative crystal displacement of similar to 40 nm. These dislocations move very slowly, suggesting that the dislocations encounter a larger resistance. Meanwhile, the dissociated superdislocations are found in the B2 phase, and the width of the antiphase domain is similar to 12 nm. Electron channeling contrast imaging (ECCI) reveals that the nucleation of microcracks on {100} cleavage planes participates in the deformation of RHESs, alongside dislocation movement, under uniaxial compression. In the process of loading, the dislocation can not rapidly accumulate to form a strain-hardening area at the crack tip, enabling unrestricted microcracks propagating, and eventually lead to catastrophic fracture. Analogous cleavage fracture characteristics are observed in in-situ tensile loading. This study provides some insights into the enhancement of the plastic deformation of RHESs.

Low-temperature brittleness has long been a critical challenge for most body-centered cubic (BCC)-structured metallic alloys, a phenomenon attributed to scarce deformation mechanisms. In this work, exceptional mechanical properties even at liquid-nitrogen temperature are intriguingly exhibited in pearlitic steel wires with lamellar structures of alternating BCC-ferrite and cementite, overcoming both low-temperature brittleness and the strength-ductility trade-off. In-depth microstructure characterizations reveal that lamellar kinking with varied morphological features in as-drawn and annealed wires serves as an essential mediating mechanism during cryogenic deformation. Molecular dynamics simulations indicate that the dominant slip system in ferrite shifts from {112}(111) to {110}(111) as temperature decreases. Nevertheless, the strong (110) fiber texture severely restricts available slip variants at liquid-nitrogen temperature, causing highly aligned atomic motion and severe shear stress concentration. To accommodate this and sustain slip, slight microstructural rotation is activated and progressively develops into micron-scale lamellar kinking. Notably, the discontinuous lamellar structure not only offers more dislocation slip channels but also undergoes kinking more readily. For kinking to operate, nanoscale cementite lamellae must possess sufficient cryogenic deformability, a prerequisite experimentally confirmed for the first time. Severe non-uniform plastic deformation facilitates rapid accumulation of geometrically necessary dislocations at phase boundaries, inducing pronounced strain gradient strengthening and thereby significantly improving work hardening capacity. Additionally, frequent yet dispersive formation of delaminations along the lamellar direction reduces the driving force for transverse disastrous crack propagation, ensuring a further enhancement of cryogenic ductility. Our findings provide new insights for comprehending cryogenic behavior of pearlitic steel wires and designing advanced metallic wires.

Whether bulk metallic glass (BMG) of unique disordered atomic structure exhibits better wear resistance than its crystalline counterpart or not, poses an essential yet unsolved question. To this motive, the wear resistances of as-cast Zr60.14Cu22.31Al9.7Fe4.85Ag3 BMG (in amorphous state), Zr60.14Cu22.31Al9.7Fe4.85Ag3 master alloy (in crystalline state), and crystallized Zr60.14Cu22.31Al9.7Fe4.85Ag3 BMG (in crystalline state), are examined using Si3N4 as the counter-friction material. Similar wear procedures are observed for the three different Zr60.14Cu22.31Al9.7Fe4.85Ag3 samples, which exhibit a running-in stage and gradually transit into dynamic stable wear stage. Intriguingly, both Zr60.14Cu22.31Al9.7Fe4.85Ag3 master alloy and crystallized Zr60.14Cu22.31Al9.7Fe4.85Ag3 BMG show a wear resistance five times better than the as-cast Zr60.14Cu22.31Al9.7Fe4.85Ag3 BMG in both air and phosphate buffer saline (PBS) solution. The main wear mechanisms of all the three Zr60.14Cu22.31Al9.7Fe4.85Ag3 samples in the dynamic stable stage are identified as ploughing, squeezing, and oxidative wear. The inferior wear resistance of as-cast Zr60.14Cu22.31Al9.7Fe4.85Ag3 BMG which shows similar nanoindentation hardness to its crystalline counterparts, is attributed to severe cracking and peeling-off of the tribo-oxide layer from the wear track. This work provides new insights into understandings on the wear resistance of BMGs and their crystalline counterparts.

ABSTRACT Doping lays the foundation for the realization of diverse functions of semiconductor devices. In layered two‐dimensional (2D) semiconductors, nevertheless, polarity mediation doping is still a major obstacle. To overcome these limitations and fully exploit the unique advantages of atomic‐scale thickness and high elasticity of 2D semiconductors, strain engineering has emerged as an effective route. Herein, lateral homojunctions are constructed in 2H‐MoTe 2 by strain engineering showing a typical photovoltaic (PV) response. Polarization responses with polarization ratios of 2.09 at 830 nm and 1.09 at 1550 nm are realized in 2H‐MoTe 2 lateral homojunctions absent in the photoconductive (PC) devices, which is closely correlated to the strain‐induced reduction in crystal symmetry revealed by the angle‐resolved polarized Raman technique. Broad detection from 520 nm to 1550 nm is illustrated both in the PC and PV devices. Peak responsivity ( R ), detectivity ( D *) and external quantum efficiency ( EQE ) arrive at 7.5 A/W, 1.2 × 10 11 Jones and 2.7 × 10 3 % at 520 nm illumination for the PV detector with a far lower response time of 25 µs than 375 µs for the PC one. This work highlights the potential of the strain engineering for advancing 2D material diverse functions of the electronics and optoelectronics devices.

Metal contacts remain one of the key bottlenecks in two-dimensional (2D) semiconductor electronics. We developed an atomic-scale step-by-step evaporation method to directly grow single-crystal metals on monolayer semiconductors with clean interfaces. This method accesses a distinct growth-kinetic window that suppresses secondary nucleation and promotes lateral coalescence, enabling van der Waals epitaxy of diverse metals-including bismuth, silver, indium, gold, and palladium-on molybdenum disulfide (MoS2) and tungsten diselenide (WSe2). The single-crystal metals support ultrathin conduction, provide spatially uniform work functions, and exhibit improved thermal robustness. As contacts, they show minimal Fermi-level pinning, approaching the Schottky-Mott limit. With bismuth and palladium contacts, monolayer MoS2 and WSe2 transistors achieved ultralow n- and p-type contact resistances of 36 and 145 ohm-micrometers, respectively, and short-channel currents both above 1.1 milliampere per micrometer.

Reactive structural materials are crucial for energy exploitation and defense applications due to their outstanding energy release characteristics. However, traditional reactive structural materials often struggle to meet the required mechanical properties. In contrast, reactive high-entropy alloys that balance mechanical performance and energy release characteristics show great potential in this field. Here, we designed the active high-entropy alloy Ti50Zr25Hf12.5Nb12.5, at% using a metastable high-entropy alloy design strategy ("d-electron alloy" strategy). The alloy exhibits a single-phase BCC structure both before and after quasi-static tension, but undergoes an impact-induced omega phase transition during dynamic tension, resulting in an unprecedented increase in yield strength from 751 MPa to 1577 MPa (an increase of 110 %). Microstructural characterization revealed that the high-density dislocation walls resulting from the omega phase transition contribute to the significant strain-rate effect of the alloy. Furthermore, direct ballistic tests demonstrated that this novel active high-entropy alloy possesses excellent energy release characteristics (similar to 0.27 MPa assessed via Vented Chamber Calorimetry in 996 m/s direct ballistic test). This work sheds new light on designing reactive high entropy alloy with high dynamic strength may provide a mean to develop a wide range of advanced reactive structural materials.

Continuous monocultures alter the composition and function of root-associated microbiota, and thus compromise crop health and productivity. In comparison, little is known about how leaf-associated microbiota respond to continuous monocultures. Here, we profiled root and leaf-associated microbiota of peanut plants under monocropping and rotation conditions. Additionally, their protective effects against root pathogen Fusarium oxysporum and leaf pathogen Alternaria alstroemeriae were evaluated. We found that monocropping increased root and leaf disease severity. Meanwhile, the peanut growth and productivity were inhibited by monocropping. Microbiota analysis revealed that monocropping reduced rhizosphere microbial population and diversity, while increased leaf epiphytic microbial population and did not influence leaf epiphytic microbial diversity. Cropping conditions had a greater impact on the microbiota composition of leaf epiphytes than that of the rhizosphere. Moreover, in vitro and in vivo experiments, combined with correlation analyses showed that monocropping weakened the antagonistic activity of rhizosphere microbiota against F. oxysporum and root rot disease. This effect may be associated with the depletion of Bacillus sp. and Sphingomonas sp.. By contrast, leaf epiphytic microbiota under monocropping exhibited greater inhibition of A. alstroemeriae growth and leaf spot control. Together, our results demonstrated a differential response pattern of root and leaf-associated microbiota to continuous monocultures.

Reactive structural materials, combining the outstanding mechanical properties and significant chemical energy-release characteristic, have a wide range of critical applications in the defense and energy fields. However, it remains challenging to achieve a synergy between high mechanical strength over 1 GPa and outstanding chemical energy release of reactive structural materials upon impact. Here, a novel TiZrHfNbAl reactive high-entropy alloy (R-HEA) possessing a monolithically body-centered cubic structure was synthesized with remarkable dynamic strength (∼1120 MPa) and superior energy-release performance [∼0.33 MPa assessed via vented chamber calorimetry in direct ballistic tests]. Utilizing high-speed photography, we developed a new method based on image processing to ascertain the characteristic time of energy release. After ballistic tests, the reaction products were collected and scrutinized. It was found that an increase in impact velocity resulted in a greater fraction of smaller fragments, signifying a thoroughly complete reaction. Utilization of x-ray diffractometers, along with energy-dispersive analysis, we facilitated the detection of fragments of varied sizes at differing velocities. The outcomes suggested that the energy-release pathway of TiZrHfNbAl R-HEA primarily revolved around redox reaction and intermetallic reactions, particularly, with a unique mechanism of micro-explosion.

Ni-free Zr-based bulk metallic glass (BMG) generally exhibits excellent combination of biocompatibility and mechanical properties, making it a potential candidate for biomedical implants. However, the in-vitro tribological behaviors and wear resistance of Zr-based BMGs still remain less understood. In this study, the wear process of a Ni-free biocompatible Zr60.14Cu22.31Al9.7Fe4.85Ag3 BMG in 3 simulated physiological environments, i. e., deionized (DI) water, 0.9 wt% NaCl solution, and phosphate buffer saline (PBS) solution, are studied using Si3N4 ceramic as the counter-material. The results indicate that Zr60.14Cu22.31Al9.7Fe4.85Ag3 BMG show a specific wear rate less than 1/3 of Ti6Al4V alloy in all the 3 simulated physiological environments, which also surpasses currently reported wear resistance of Zr-based BMGs in the same environments. Specifically, the wear process of Zr60.14Cu22.31Al9.7Fe4.85Ag3 BMG shows a 3-staged character, i.e., the running stage, the transition stage, and the dynamic stable stage, with the main wear mechanism transiting from adhesive wear to coexistence of adhesive wear and oxidative wear, and eventually to oxidative wear. During the transition of wear mechanism, the formation of oxide layer on the worn surface plays the key role, which provides protection against wear and leads to better wear resistance. Notably, the relatively higher wear rate of Zr60.14Cu22.31Al9.7Fe4.85Ag3 BMG in 0.9 wt% NaCl solution and PBS solution than that in DI water is attributed to the corrosivity of wear environments, which weakens the adhesion between oxide layer and BMG substrate thus promoting spalling of oxide layer and enhancing wear degradation. These results indicate the synergistic effect of corrosion and wear in Zr-based BMG in simulated physiological environments. Our work provides insights in developing wear-resistant Zr-based BMGs for implantable biomaterials.

In amorphous solids, shear transformations, as elementary rearrangement events operating in local regions, are intrinsically entangled with dilatation deformation, which results in the physical process of the shear band being complex. To capture such entanglement, we propose a finite-deformation continuum framework for amorphous solids by incorporating nonequilibrium thermodynamics. Within this framework, we develop a constitutive model where the thermodynamic glass is divided into the kinetic and configurational subsystems. In the model, the dilatation is attributed to an athermal expansion of configuration. As a result, the effect of shear transformation on dilatation can be considered by generating plastic cold work to change the freedom degrees of the configurational subsystem. The effect of dilatation on shear transformation can be realized through the enthalpy change of the configurational subsystem that gives rise to physical aging. Based on the proposed model, we discuss the entangling mechanism of shear and dilatation, and predict the shear-banding behaviors of metallic glasses during tensile and compressive deformations at room temperature. We reveal that due to the shear-dilatation entanglement, the elastic deformations significantly influence the evolution of configurational temperature, which plays a pivotal role in controlling the degree of strain softening and the shear-banding mode.

The CoCrNi medium entropy alloy (MEA) demonstrates superior mechanical performance when compared to CoCrFeNi MEA and CoCrFeMnNi high entropy alloy (HEA) with similar microstructures, primarily due to its lower stacking fault energy. However, research into the fundamental distinctions in their local atomic structures and how these variations impact mechanical properties remain limited. This study employs in-situ neutron diffraction during uniaxial tension tests and extended X-ray absorption fine structure (XAFS) spectra before and after testing to investigate factors contributing to performance differences. Neutron diffraction results present notable disparities in the lattice strain evolutions among the three alloys, with CoCrNi MEA demonstrating the highest dislocation density, particularly, at during the late-stage deformation. More active dislocation movements in CoCrNi MEA contribute to its enhanced ductility compared to CoCrFeNi MEA and CoCrFeMnNi HEA. The EXAFS results indicate that while CoCrNi MEA exhibits the smallest lattice distortion, it tends to form shortrange order Ni-enriched clusters that likely enhance its strength. For CoCrFeNi MEA and CoCrFeMnNi HEA, the degrees of local lattice distortions correspond well with their strengths, which highlight the importance of lattice distortion to strength, even when these distortions are not severe. This study unequivocally underscores those subtle distinctions in the local atomic structure among these three alloys profoundly influence their mechanical performance.

Long-rod projectiles (LRPs) with deep penetrability have been widely used in the defense industry. LRPs made of self-sharpening materials can maintain a sharp head due to the formation of shear bands during the penetration process, which greatly improves their penetrability. However, due to the complexity of extreme conditions, the mechanism of self-sharpening penetration is still unclear. Here, a semi-fluid self-sharpening penetration model that includes the self-sharpening effect is proposed. The model reveals that the self-sharpening effect can effectively enhance the penetrability by reducing the expansion resistance of the target and the deceleration of the projectile. The penetration depth predicted by the theoretical model is in good agreement with the experimental results. It is further found that the disappearance of the self-sharpening phenomenon as the penetration speed increases is determined by the competition between shear band propagation and projectile erosion. Furthermore, it is revealed that projectile materials with high Johnson damage number, low Eckert number, and high Prandtl number were identified as more prone to exhibiting self-sharpening behavior. This may provide some new insights for designing self-sharpening heavy alloy and developing advancing LRPs. (c) 2025 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution-NonCommercial 4.0International (CC BY-NC) license (https://creativecommons.org/licenses/by-nc/4.0/)

Refractory high-entropy superalloys (RHESs) offer transformative potential for high-temperature applications, but face significant challenges in engineering applications. This study investigates the strengthening mechanisms for different phases and phase stability of the AlMo0.5NbTa0.5TiZr RHESs, which features a gamma/gamma '-like A2/B2 dual-phase nanostructure. Based on Energy-dispersive X-ray spectroscopy (EDS) analysis, the composition of the BCC phase in this RHESs was identified and corresponding alloys were successfully synthesized. Uniaxial compression tests reveal temperature-dependent synergy between BCC and B2 phases: while both phases exhibit near-equal strength contributions at elevated temperatures (600-800 degrees C), mechanistic analysis revealed distinct origin that the BCC phase derives strength from solid-solution effects dominated by lattice distortions, whereas the B2 phase provides order-strengthening through antiphase boundary energy barrier. Meanwhile, it has been fully demonstrated that incorporating high-modulus and large atomic-size elements (e.g., Mo, Zr, Cr) effectively enhances solid-solution strengthening in single-phase RHEAs. In-situ transmission electron microscopy (TEM) heating experiments uncover rapid coarsening of BCC precipitates driven by spinodal decomposition. The microstructural instability to elemental redistribution was found to be linked to Nb/Ta-Zr miscibility gaps. These findings provide critical guidelines for designing RHEAs suitable for high-temperature engineering applications.