This study presents an innovative approach to overcome Cu-based materials’ inherent limitations (inadequate wear/corrosion resistance) and the alloying challenge of the immiscible Cu-Mo system. Using ultra-high-speed laser cladding, we fabricated Cu-Mo cladding layer with optimized parameters via Box-Behnken Design (BBD) response surface methodology, with three key variables: laser power (2500–4000 W), scanning speed (100–200 mm/s), and powder feeding rate (1.5–2.5 r/min). Comprehensive characterization techniques including X‑ray diffraction (XRD), Scanning Electron Microscope (SEM), Energy‑dispersive X‑ray spectroscopy (EDS), microhardness testing, and electrochemical analysis, complemented by laser power single-factor experiments, elucidated the underlying mechanism of laser power-regulated Mo particle dissolution-dispersion and its correlation with the microstructure-performance of Cu-Mo cladding layer. Results showed scanning speed and powder feeding rate were predominant in controlling cladding thickness. At the optimal 3000 W, Mo particles uniformly dispersed in the Cu matrix, achieving 0.99

The high current pulsed electron beam (HCPEB) technique is a valuable method for improving the surface properties of materials. In the present study, multi-layer TiCN/Al2O3 coatings with varying thicknesses of TiCN and Al2O3 layers were prepared using a chemical vapor deposition (CVD), followed by HCPEB irradiation. The microstructure and properties of the coatings were analyzed before and after irradiation. As the irradiation pulse increases, the surface of the coating with a 1-mu m-thick Al2O3 layer gradually becomes smoother and forms a honeycomb structure. In contrast, the coatings with 8 mu m-thick Al2O3 layer exhibited crater-like formations and a rolling structure due to the subsurface eruptions, although they also showed a general trend toward a surface smoothing. The nanohardness of both coatings first increases and then decreases. The coatings with 1 mu m-thick Al2O3 layer exhibited highest nanohardness (19.985 GPa), lowest friction coefficient (0.202), and lowest wear rate (2.86 x 10-6 mm 3 N-1 m- 1 ) after 10 irradiation pulses. In comparison, the coatings with 8 mu m-thick Al2O3 layer reached their peak nanohardness (16.441 GPa), lowest friction coefficient (0.242), and lowest wear rate (2.80 x 10-6 mm 3 N-1 m- 1 ) after 15 irradiation pulses. Additionally, both HCPEB irradiation pulses and coating thickness significantly affected the level of residual stresses in the coatings. For the coatings with 1 mu m-thick Al2O3 layer, the residual stresses initially transitioned to tensile stress state before shifting to compressive stress state after irradiation. In contrast, the residual stresses in the coatings with 8 mu m-thick Al2O3 layer consistently changed to compressive stress state. This study analyzed the microstructure and properties of coatings under different pulses, and evaluated the modification potential of HCPEB in high-performance coatings.

In this paper, we predict a series of two-dimensional pentagonal transition metal dichalcogenides (TMDCs), including penta-ZnX2(X = S, Se, Te) with α- and β-configurations, based on first-principles calculations. The predicted monolayers have extremely low Young’s moduli, indicating high flexibility and broad potential applications in flexible devices. Notably, the β-phase displays novel mechanical properties, namely negative Poisson’s ratio (NPR), with a significant auxetic effect. Additionally, penta-ZnX2 monolayers exhibit excellent tunable bandgaps and suitable redox potentials, particularly under conditions crossing water. Besides that, β-phase monolayers have good optical properties, with the dielectric function energy range. Therefore, these materials demonstrate significant potential for photocatalytic water splitting. These findings promise candidate materials for scalable nanomechanics, nanoelectronics, and photocatalytic water splitting catalysts.

In this paper, high-current pulsed electron beam (HCPEB) technology was used to modify an Al-W alloying layer prepared by laser surface alloying (LSA). The microstructural changes were characterized by scanning electron microscope (SEM), X-ray diffractometer (XRD) and transmission electron microscope (TEM). The microhardness and friction properties were tested to explore the mechanism behind the performance enhancement. After HCPEB irradiation, the Al-W particles were dissolved and diffused to form a homogeneous re-melt layer on the topmost surface of Al-W laser-alloyed layer, approximately 20 mu m thick. The phase compositions of the alloying layer consisted of alpha-Al, Al12W, Al5W, and Al4W phases. Additionally, HCPEB irradiation induced the formation of ultrafine crystals and a variety of crystal defect structures in the topmost Al-W laser-alloyed layer. The hardness of the Al-W laser-alloyed layer was significantly enhanced after HCPEB irradiation. Furthermore, the friction and wear properties of the alloying layer were significantly improved, which was mainly related to the formation of an abundant dislocation structure, Al-W particles and grain refinement.

This study is aimed at investigating the Mo0.5NbTiZrAlx (x = 0.3, 0.5, 0.7) high-entropy alloys (HEAs) produced via arc melting. The microstructure, microhardness, wear resistance, and corrosion resistance of alloys were studied systematically. The results revealed that Mo0.5NbTiZrAl0.3 and Mo0.5NbTiZrAl0.5 compositions had a single BCC phase structure, while the Mo0.5NbTiZrAl0.7 composition exhibited a BCC+B2 phase structure. Meanwhile, the alloys exhibited the typical dendritic morphology. The increase of Al content promoted grain refinement and crystal orientation randomization. It also enriched the defect structure within the alloys and induced the occurrence of spinodal decomposition phenomenon. Moreover, the increase in Al content significantly improved the hardness and wear resistance of alloys, which was attributed to synergistic effects of tough BCC phase, solid solution strengthening, B2 phase strengthening, fine grain strengthening, and dislocation strengthening. In addition, the electrochemical tests confirmed that the increase of Al content inhibited the improvement of corrosion resistance due to the growth of Al2O3 films aggravated the erosion by Cl-.

The interfacial structure and mechanical performance of diffusion-bonded Ti2AlNb/GH536 joints with high-current pulsed electron beam (HCPEB) pretreatment were systematically investigated. Through multi-scale characterization and diffusion dynamics analysis, it could be demonstrated that HCPEB-induced surface fine grains and high-density crystal defects (dislocations, twins, vacancy clusters) synergistically enhance atomic diffusion kinetics. At optimal bonding temperature (900 degrees C), the modified joints achieved a 38.8 % increase in shear strength (186 MPa vs. 134 MPa for original joints), accompanied by fracture mode transition from brittle cleavage to quasi-cleavage with ductile dimples. The enhanced performance is attributed to: (1) reduced diffusion activation energy; (2) suppressed growth of brittle Ti-Ni intermetallics; (3) formation of Cr-rich/Nipoor solid solutions. This work provides critical insights into defect-engineered dissimilar joining for aerospace applications.

Nano-multilayered TiN/AlSiN coatings deposited onto cemented tungsten carbide substrates by arc ion plating have been subjected to high-current pulsed electron beam (HCPEB) treatment. The impact of pulse number on the surface morphology, phase composition and mechanical properties of the TiN/AlSiN coatings were investigated. A microstructural evolution from a superlattice structure to a composite structure was noticed using transmission electron microscopy. The surface morphology of the coatings first deteriorated due to irradiationinduced coating peeling-off and cracks, and then improved with a further increase in HCPEB pulse number, as the surface roughness value reached a maximum of 0.42 mu m after 5-pulse of HCPEB irradiation and a minimum of 0.22 mu m after 15-pulse of irradiation. An increase of HCPEB pulse number led to a gradual decrease in both hardness (H) and elastic modulus (E) of these coatings, as the values of H and E dropped from 34.0 GPa and 439.7 GPa (original TiN/AlSiN coating) to 26.2 GPa and 399.6 GPa (the coating treated with 20-pulse of irradiation), respectively. The degradation in mechanical properties was due to microstructural change and the formation of the network of cracks.

The auxetic behavior in nanostructures has attracted considerable attention due to their wide potential applications. Due to the long-standing attribution of auxetic properties to the unique geometric structure of materials, the academic community's understanding of auxeticity is not profound. It is considered to have no access to tuning the auxeticity without phase transition. In this letter, an anomalous case is discovered where the auxetic transition is directly driven by the electronic correlation in Janus-Tetra-SiXY (JT-SiXY; X, Y = O, S, Se) lattice. The auxeticity is highly dependent on the electronic properties. Additionally, the auxeticity is significantly enhanced due to the Janus modification. The emerging auxetic transition effect and enhanced auxeticity would make JT-SiXY a promising candidate in two-dimensional nano-devices. Our study provides valuable clues and useful guidance for designing advanced auxetic materials.

The aim of this study is to investigate the microstructure and properties of the Al-Mo - Mo laser-alloyed layer induced by high-current pulsed electron beam (HCPEB) irradiation. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were utilized to investigate the microstructures of the modified layer. The microhardness and friction properties were also measured. The microstructural observation shows that HCPEB irradiation led to the formation of a modified layer approximately a dozen microns thick, which was the absence of the pores. It was found that the flower- and strip-like Al-Mo - Mo particles were dissolved to form nano-size particles consisting of Al5Mo 5 Mo (h2), Al12Mo, 12 Mo, and Al17Mo4 17 Mo 4 phase after HCPEB irradiation. Additionally, the slip bands and high-density dislocations were formed in the modified layer. The refined microstructure significantly enhanced the microhardness of the laser-alloyed layer. A quantitative evaluation was conducted to investigate the individual contributions of four strengthening mechanisms to the strength of the modified layer, which indicated that dislocation and grain boundary strengthening were dominant. The results of sliding wear tests show that the modified layer exhibited superior properties compared to the laser alloying layer, which was attributed to the formation of crystal defects, solid solutions, and nanoparticles.

This study investigates the influence of high-current pulsed electron beam（HCPEB） modification on the microstructure and shear strength of Cu/CuW joints.Reliable solid-state diffusion bonding of modified-Cu（MCu） and modified-CuW（M-CuW） was achieved by HCPEB modification pretreatment at a temperature of 800-900 ℃ and a pressure of 5 MPa for 10-50 min.Experiments demonstrate that HCPEB modification facilitates the dissolution of W and Cu,resulting in the formation of a Cu 0.4 W 0.6 solid solution and thus enhancing the uniform distribution of microstructures.Additionally,HCPEB-induced defects play a beneficial role in promoting the diffusion process by providing fast diffusion paths for elements.The optimal joints with the maximum shear strength of 213.7 MPa were obtained through bonding M-Cu and M-CuW at 900℃ and 5 MPa for 30 min,which attributes to the combined effects of fine-grained strengthening and solid solution strengthening.Overall,the application of HCPEB modification showcases its effectiveness in promoting element diffusion and enhancing the mechanical performance of the joints.

In this work, a TiN/TiCN/Al2O3/TiN coating deposited onto cemented carbide matrix by chemical vapor deposition was irradiated by high-current pulsed electron beam (HCPEB). The influence of pulse times on the phase composition, microstructure, and mechanical properties of the coating investigated. The results showed that no new phase was produced, the grain size of the coating surface was refined, the surface became flat, and the surface roughness decreased after HCPEB treatment. The TiN/TiCN/Al2O3/TiN coating presented a smooth surface with good mechanical performance after HCPEB. A maximum hardness was obtained after 15 pulses, and the 15-pulse irradiated coating showed better wear resistance. The improvement in the coating’s performance after irradiation was mainly attributed to the formation of grain refinement and crystal defects, as well as the change of stress field inside the coating. The objective of this study was to evaluate the potential of HCPEB modification in the preparation of high-performance coating by analyzing the microstructure and property of coating under different pulses.

The intrinsic auxeticity of materials has long been attributed to their unique geometric configurations. Triggering and enhancing auxeticity presents significant challenges, as many nanomaterials display subtle auxetic effects with a negative Poisson's ratio (NPR) typically above -0.4. This paper introduces three materials with identical symmetry—two-dimensional pentagonal structures Penta-B2X2Y2 (i.e., Penta-B2C4, Penta-B2N4, and JP-B2C2N2)—to investigate a novel mechanism influencing material auxeticity: electron transfer. Specifically, variations in electron transfer cause Penta-B2N4 and JP-B2C2N2 to show axial auxetic effects, whereas Penta-B2C4 demonstrates opposite behavior. The axial NPR of Penta-B2N4 is ~ -0.05, while for JP-B2C2N2, it reaches ~-0.46, significantly surpassing that of typical intrinsic auxetic materials. This represents an increase of approximately 920% compared to Penta-B2N4. Additionally, JP-B2C2N2 features semi-metallic properties, where the conduction band minimum (CBM) and the valence band maximum (VBM) are tangent to the Fermi level. Consequently, minor alterations in external conditions can induce a transition between semiconductor and metallic states in JP-B2C2N2. Thus, the 2D material JP-B2C2N2 emerges as a promising candidate for nanoelectronic and electromechanical applications. Furthermore, this study also enhances the academic understanding of auxetic properties in nanomaterials by linking their mechanical and electronic characteristics and laying a theoretical foundation for further experimental exploration of auxeticity.

High current pulsed electron beam (HCPEB) irradiation is an important surface engineering technique, which has been proved to be valid in modifying the surface microstructure and properties of various materials. In this work, HCPEB was employed to irradiate TiAlN coatings. The microstructure, mechanical and tribological properties of both original and irradiated TiAlN coatings were investigated. The results showed that the surface roughness of the TiAlN coatings first increased with 5 pulses of HCPEB irradiation, and then gradually declined with a further increase in pulse numbers. Compared with the original coating, the coating irradiated by 15 pulses demonstrated superior hardness (up to 33.4 GPa) and adhesion strength (112N), excellent wear resistance (wear rate of 3.3 x 10-6 mm3/Nm) and low friction coefficient (0.37). It is believed that the grain refinement, formation of the transition zone and adjustment of residual stresses after 15 pulses of HCPEB treatment are responsible for the improvement in both mechanical and tribological properties of the TiAlN coatings. These findings might suggest the potential applications of HCPEB irradiation for surface modification and hardness improvement of hard nitride coatings.

MCrAlY-type coatings are widely applied to thermally loaded structures of aero-engines as standalone overlays and as a bond-coat for a thermal barrier coating system, owing to their good resistance to high-temperature oxidation and hot corrosion. The thermally grown oxide (TGO) formed at the interface is the primary factor affecting the durability of MCrAlY coatings, which is closely related to the coating method used. The coating performed by low-pressure plasma spraying (LPPS) has great adhesion, high deposition rate, and low internal oxidation. However, the prepared defects of rough surface and porosity adversely affect the antioxidant performance. High-current pulsed electron beam (HCPEB), as a powerful tool for surface modification of different materials, can normalize the defects, polish the coating surface, and reconstruct microstructures, which is crucial to promote steady growth of the protective TGO. Therefore, in this work, NiCrAlY coatings were prepared on the surface of a nickel-based superalloy via LPPS and then irradiated via HCPEB. The microstructural evolution, static oxidation performance at 1150 degrees C, and TGO residual stress distribution of NiCrAlY coatings before and after HCPEB modification were compared. The microstructural results show that the surface of the as-sprayed coating was rather rough and there were many unmelted large particles. After HCPEB irradiation, the surface of the irradiated coating was remelted, and became much flat and smooth. A rather dense and compact remelted layer approximately 12 mu m in thickness was obtained. Furthermore, deformation structures and Y-Al enriched nanodispersed particles were introduced inside the remelted layer. The results of static oxidation and TGO residual stress show that after 150 h of oxidation, the oxide film formed on the as-sprayed coating fell off locally, accompanied by serious internal oxidation. Due to the cracking and peeling of the TGO, the internal stress was released. Conversely, the oxide film on the remelted surface of HCPEB irradiated coating grew steadily, and there was no trace of peeling, and the TGO stress increased steadily. The experimental results show that HCPEB is an effective and promising approach to drastically improve the high-temperature oxidation resistance of thermally sprayed MCrAlY coatings.

Layered auxetic materials have an acute demand for the in-plane negative Poisson's ratio (NPR) due to dimensional restrictions. Yet, it is not yet apparent and developed where the auxeticity in nanomaterials origins from. Aimed at inserting in-plane auxeticity, in this letter, we theoretically propose a series of Si2O-based layer-stacking materials using a bottom-up strategy. As a result of the materials' chemical O absorption, which causes the Pauli repulsion of inter-layer orbits to shift in the direction of the plane, a newly found multi-directional NPR effect is finally realized in II-BK-Si2O. Furthermore, the multilayer structures preserve dispersion of the SL-Si2O while breaking the semi-Dirac semi-metallic conditions and gapped, endowing the materials semiconducting characteristics and strong carrier mobilities. For Si2O-based materials, the aforementioned benefits open up a wide range of application possibilities and research potential.

In this study, the Mo0.5NbTiZrTax (x = 0.3, 0.5, 0.7) HEAs obtained by arc melting were controlled by the change of Ta content. The microstructure, the wear properties, and the corrosion resistance of the alloys were studied systematically. The results revealed that the alloys have the BCC (major) phase + BCC (minor) phase structure. At the same time, the increase in Ta content promotes the refinement of grains and the formation of sub-grains with gradually random orientation at grain boundaries but suppresses the randomization of crystal orientation. This also enriched the defect structure inside the alloys, further induced the formation of Zr-rich second phase particles, high-density stacking fault structures, and disordered Zr-rich BCC phases. The increase in Ta content significantly improved the wear properties of the alloys, which is mainly ascribed to the presence of the tough BCC phase and the combined effects of solid solution strengthening, second phase strengthening, fine grain strengthening, lattice distortion effect, and stacking fault strengthening. The electrochemical measurements confirm that the overall corrosion resistance of the alloys shows a trend of first increasing and then decreasing with the increase of Ta content due to the formation of micro batteries between the second phase rich in Zr as the anode and dendrites.

In this work, a TiN/TiCN/Al2O3/TiN coating deposited onto cemented carbide matrix by chemical vapor deposition was irradiated by high-current pulsed electron beam (HCPEB). The influence of pulse times on the phase composition, microstructure, and mechanical properties of the coating investigated. The results showed that no new phase was produced, the grain size of the coating surface was refined, the surface became flat, and the surface roughness decreased after HCPEB treatment. The TiN/TiCN/Al2O3/TiN coating presented a smooth surface with good mechanical performance after HCPEB. A maximum hardness was obtained after 15 pulses, and the 15-pulse irradiated coating showed better wear resistance. The improvement in the coating’s performance after irradiation was mainly attributed to the formation of grain refinement and crystal defects, as well as the change of stress field inside the coating. The objective of this study was to evaluate the potential of HCPEB modification in the preparation of high-performance coating by analyzing the microstructure and property of coating under different pulses.

CoCrFeNiZr0.3 is a two-phase coexisting (Laves + FCC) high-entropy alloy with high strength, excellent corrosion resistance, and thermal stability. However, the inhomogeneous distribution of the eutectic structure among the dendrites has a detrimental effect on the coordinated deformation of the material. The current study shows that the grain size, weave structure, and second phase distribution of high-entropy alloys can be significantly changed by thermal deformation, which affects the mechanical and physical properties, as well as the chemical stability of the alloys. In this study, the thermal deformation behavior of CoCrFeNiZr0.3 biphasic hypoeutectic high-entropy alloy was investigated using a Gleeble-3500 thermal simulation tester under the conditions of deformation temperature of 950–1100 °C and deformation rate of 0.001–1 s−1. The results show that CoCrFeNiZr0.3 high-entropy alloy has higher deformation activation energy, which means its deformation resistance is larger. In addition, the microstructure with finer grain size and uniform distribution of Laves phase can be obtained by EBSD analysis after compression at 1000 °C and 0.01 s−1.

Carbon-based materials that process a wide bandgap, high mechanical performance, thermal stability and adjustable characteristics are in high demand.

In this paper, a Cu–Mo alloying layer with improved properties was fabricated by high current pulsed electron beam (HCPEB) irradiation. The microstructure of the modified layer was investigated by x-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The microhardness and friction properties were also measured. After HCPEB irradiation, nano Mo particles, solid solution, and long-period superlattice structures were generated on the surface of Cu–Mo alloys, together with the formation of defect structures. These microstructures led to a significant increase in the surface hardness. The results of sliding wear tests indicated that the HCPEB-irradiated samples exhibited better properties compared with the initial one, which was attributed to the ultrafine Mo particles and the hardened surface.