Achieving sustained self-lubrication and structural integrity of titanium alloys under heavy-load conditions remains a considerable challenge. This study proposes a bio-inspired hexagonal surface in which laser-induced micro-reservoirs are synergistically coupled with pressure-responsive composites to enable load-responsive solid lubrication under dynamic heavy loads, thereby enhancing self-lubrication and anti-wear. By structurally mimicking the hexagonal microchannels in tree frog toes and functionally replicating the pressure-release particles within insect joints, the bio-inspired surface is fabricated to enable stress-activated solid lubrication release in response to dynamic contact stress. The results reveal that the storage-extrusion behavior is predominantly influenced by leveraging variations in the mechanical stability of embedded solid lubrication. While the pure PTFE sample suffers from oxidative abrasive wear due to severe rheological instability, and the Graphene Oxide-reinforced sample succumbs to brittle structural delamination, the MXene-reinforced composite (LPM2) exhibits exceptional anti-wear robustness. Specifically, the rigid MXene network anchors the soft matrix, suppressing macroscopic plastic flow and resulting in the in-situ compaction of nano-sized debris into a dense, oxidation-resistant tribofilm. This synergistic interaction reduces wear volume by 94.4% under a rigorous 10 N load. These findings illuminate engineering design principles that integrate bio-inspired texturing with nanostructural reinforcement.

In this study, a defect-free NiTi/Cu/SS welded joint was successfully fabricated using a Cu interlayer via cold metal transfer welding. Due to the diffusion of Ni and Ti elements, intermetallic compounds such as TiCu, Ti2Cu, Ti2Cu3, TiCu2, and TiCu4 were observed at both the NiTi/Cu and Cu/SS interfaces. The joint strength was enhanced by the solid-solution strengthening effect of the dissolved Ni and Ti elements, coupled with the formation of TixCuy intermetallic reaction layers. Consequently, the NiTi/Cu/SS joint achieved a tensile strength of 262 MPa.

Superelastic alloys for critical applications in extreme environments are required to combine a wide operating temperature range, low temperature sensitivity, and high strength. Achieving this combination is challenging. Drawing from high-entropy and superelastic alloy design principles, this study utilised laser-directed energy deposition (L-DED) to fabricate TiZrHfNiCu high-entropy superelastic alloys with excellent forming quality. The intricate composition and swift solidification conditions resulted in a uniform, fine, and isotropic dendritic microstructure within this high-entropy alloy, which comprises the B2 phase, B19' phase, and Zr2Cu-like phase. In comparison to the as-cast material, the LDED-TiZrHfNiCu material exhibits a reduced degree of component segregation and concurrently experiences strain glass transition alongside martensitic crystallisation behaviour. The alloy demonstrated recoverable superelastic strains exceeding 5%, a fracture strength over 2 GPa, and very low temperature sensitivity between 173 K and 473 K. Additionally, this method addresses the difficulties associated with machining superelastic alloys and the challenges associated with manufacturing complex geometries. This study illustrates the fabrication of TiZrHfNiCu alloy via L-DED, offering a new perspective on the preparation of high-strength, wide-temperature-range superelastic alloys and providing insights into phase-structure transformations and microstructural evolution in additively manufactured high-entropy superelastic alloys. This study demonstrates the feasibility of using L-DED technology to fabricate high-performance high-entropy shape memory alloys.Refined composite microstructures were achieved under non-equilibrium solidification conditions.The (TiZrHf)(5)(0)(NiCu)(5)(0) alloy fabricated by L-DED exhibits high strength and stable superelasticity over a wide temperature range.The interplay between compositional segregation and composite microstructure promotes the coordinated occurrence of reversible martensitic transformation and strain glass transition.This study established correlations between the manufacturing process, microstructure, and mechanical properties.

High-performance impact-resistant materials can improve structural protection by regulating the transfer and distribution of impact loads. However, existing designs often rely excessively on a single energy dissipation mechanism. Inspired by the plunger structure of the snapping shrimp chela, this study systematically characterizes its mechanical properties, microstructure, and elemental composition. The results show that the structure exhibits a multilevel structure with two zones and four components. CaCO3 is the major constituent and shows a longitudinal spatial gradient. Its excellent impact resistance is mainly attributed to a synergistic energy dissipation mechanism involving strength-dominated damage and constrained buckling. Drop-hammer impact tests further show that the peak impact load of the biomimetic specimen is about 1.17 times that of the control structure. This work provides useful guidance for the design of high-performance impact-resistant structures in aerospace, deep-sea exploration, and related fields.

The Ti-6Al-4V alloy produced by laser powder bed fusion (LPBF) is severely limited in its service life in extreme aerospace environments due to insufficient high-temperature oxidation resistance and corrosion resistance (range at 600-800 degrees C). This study prepared Ti64-xMo alloys (x = 0, 0.05, 0.5, 5 wt%) using LPBF technology, aiming to enhance their corrosion resistance through LPBF-specific regulation of non-equilibrium microstructures. The results indicate that the addition of Mo induces a transition from a typical 'basket-like' structure to a fine 'lava-like' structure, characterized by distinct beta grain boundaries and an increased volume fraction of the beta phase. The corrosion current density of the Ti64-5Mo alloy at 25 degrees C decreased by four orders of magnitude (from 10-2 to 10-6 A/cm2), and its corrosion resistance at 800 degrees C was significantly improved, reducing the corrosion rate by approximately 50%. This structure facilitates the generation of a dense protective layer on the surface and enhances the adhesion of the oxide layer, effectively preventing its spalling and achieving outstanding high-temperature protective performance. This work establishes LPBF-specific structure-property correlations for wide-temperature-range corrosion performance.

Root analogue implants (RAIs) provide a superior anatomical fit and immediate placement compared to traditional screw-threaded implants. However, the stiffness mismatch between Ti6Al4V and natural bone often results in stress shielding and compromised long-term stability. In this study, sine-wave honeycomb porous structures with tunable Poisson’s ratio and Young’s modulus were optimised from conventional honeycomb structure via finite element analysis (FEA). The selected structures were then fabricated via laser powder bed fusion (LPBF) and experimentally validated using digital image correlation (DIC). The sine-wave honeycomb structure was incorporated into a porous RAI design and evaluated through FEA for stress shielding, bone resorption, and fatigue performance. Compared with solid, conventional honeycomb, and TPMS gyroid counterparts, the sine-wave honeycomb RAI exhibited the lowest stress shielding (2.40% vs. 29.07% for solid RAI), minimal bone resorption (7.71% vs. 24.62% for solid RAI), and the highest fatigue safety factor (Soderberg fatigue factor: 1.34 vs. 1.16 for TPMS gyroid and 0.71 for conventional honeycomb). These results demonstrate that the sine-wave honeycomb RAI effectively mitigates stress shielding and bone loss while maintaining structural integrity, offering a promising strategy for next-generation porous dental implants.

Ceramic materials are valued in aerospace, automotive, and protective applications for their high-temperature stability, corrosion resistance, and hardness, but their inherent brittleness limits simultaneous improvement of strength and toughness. Inspired by natural architectures, a fabrication strategy integrating material extrusion, ultrasonic-vacuum-assisted cyclic metal infiltration, and stepwise vacuum heat treatment is proposed for ceramic-metal composites. Microstructural and phase analyses indicate that the metallic phase effectively infiltrates the porous ceramic scaffold and forms stable interfaces. Mechanical tests show that the composites with optimized heat treatment and about 4.6 wt

Bone scaffolds must simultaneously provide high porosity for tissue ingrowth and sufficient mechanical properties to sustain physiological loading, yet achieving this balance remains difficult. We report loofah-inspired hierarchical porous NiTi/hydrogel composite scaffolds with dual-scale porosity (including millimeter-scale and micrometer-scale pores), fabricated by laser powder bed fusion (LPBF) followed by hydrogel infiltration and freeze-drying. Inspired by the fibrous network of loofah and guided by topology optimization further, the scaffolds exhibit tunable porosity (55%-80%) and show an optimized balance between porosity, stiffness, and strength that closely mimics natural bone. Under compression, the loofah-like structure enables radial stress redistribution and gradual crack propagation, avoiding the abrupt failure observed in periodic lattices. The corresponding finite-element analysis (FEA) accurately captures the deformation behavior and validates the stress-transfer mechanism. Scaffolds with intermediate porosity (60%-70%) achieve stiffness comparable to cancellous bone (0.55-1.14 GPa) and strength approaching cortical bone (64-124 MPa), while maintaining excellent cyclic stability (irreversible strain=1.51%). In vitro cytocompatibility tests using human osteoblasts confirm good cell viability and adhesion, which are attributed to the micrometer-scale pores (average size ∼127 μm) and the excellent biocompatibility of both the hydrogel and NiTi alloy. This work demonstrates that a bioinspired, hierarchically porous composite design can reproduce bone-like mechanical performance through an integrated material–structure–function design, offering a rational strategy for architecting load-bearing and biocompatible scaffolds.

High-Fidelity Simulation of the Directed Energy Deposition (DED) Process is needed to move from trial-and-error manufacturing to predictability. In this paper, a physics-based numerical framework is developed to connect the macro-scale powder transport and the mesoscale melt pool evolution through integrating temperature-dependent boundary conditions and stochastic particle statistics. An Eulerian–Lagrangian formulation is utilized to simulate turbulent carrier gas and discrete powder stream. To accurately characterize particle and substrate interactions near the moving laser heat source, a temperature-sensitive capture and rebound criterion is incorporated as an interfacial boundary condition governed by the local phase state and surface tension variations. In addition, a Monte Carlo–based stochastic distribution converts discrete particle trajectories into a continuous volumetric mass source, coupled with the Volume of Fluid method to resolve transient thermocapillary convection and free-surface evolution. The framework is validated for various laser powers for single track depositions and for various overlapping ratios for multi-track depositions. The predicted clad track morphologies demonstrate excellent agreement with experimental cross-sections, with geometric deviations strictly restricted within 7%. This physics-driven framework provides a reliable basis for generating high-fidelity dataset assets to promote machine learning modeling and model order reduction in DED processes.

The thermal history nonuniformity during metallic additive manufacturing induces heterogeneity in microstructures and mechanical properties, which remains a critical challenge to the component performance. In this work, a high-throughput parameter optimisation algorithm is developed to allocate laser power on each deposition track so as to reduce thermal history nonuniformity in directed energy deposition (DED). Firstly, a numerical surrogate model is developed to infer the multi-layer transient temperature fields efficiently. In the model, a matrix-wise computational workflow is introduced, which substantially accelerates computational speed and reduces inference time for optimisation evaluations. In addition, a heuristic optimisation algorithm is proposed to allocate laser power parameters on each deposition track, where the standard deviation of cross-track temperature integrals serves as the objective metric and is minimised to achieve a uniform thermal history. In the experiments, the optimised manufacturing strategy suppresses over 57% of the thermal history nonuniformity. The component fabricated with optimised parameters achieves an average improvement of 33% in mechanical property homogeneity and enhanced ductility without sacrificing tensile strength. It highlights the practical value of reducing thermal history nonuniformity to improve mechanical reliability and mitigate the strength-ductility trade-off in DED-fabricated components.

Endogenous signaling molecules are essential for coordinated wound healing, yet current donor-based dressings typically provide only single-mediator delivery with limited release duration. Here, a multifunctional hydrogel dressing, HEVCTM, is developed by free radical copolymerization of N-hydroxyethyl acrylamide (HEAA) with a hydrogen peroxide (H2O2) releasing donor (VIM-CAT) and a hydrogen sulfide (H2S) releasing donor (TBA-MA). The hydrogel enables temporally programmed release, with rapid H2O2 delivery within 24 h for early stage antibacterial action and sustained H2S release for up to 7 days to alleviate inflammation and promote angiogenesis during later healing stages. HEVCTM exhibits potent antibacterial activity against (99.6%) and (99.97%), significantly enhances macrophage M2 polarization (52.4%), and shows favorable antioxidant, hemostatic, adhesive, and pro-angiogenic properties. Moreover, in an infected mouse wound model, HEVCTM significantly accelerated wound healing and promoted tissue regeneration. This work provides a bioactive hydrogel platform that matches the dynamic requirements of wound healing and effectively accelerates tissue repair.

Superamphiphobic surfaces, inspired by the springtail re-entrant microstructure array skin, have wide applications in environmental protection, chemical engineering and biomedicine. However, due to the complex geometry of re-entrant microstructures, it remains difficult to fabricate large-area re-entrant microstructure arrays on metal surfaces without expensive equipment and complex processing techniques. Here, by combining the nanosecond laser direct writing technology with the template-assisted transfer technology, we developed an efficient, low-cost, and large-area manufacturing technology for superamphiphobic surfaces on metal substrates. The prepared surfaces demonstrate a strong ability to repel low surface tension droplets, such as hexadecane (surface tension: gamma = 27.2 mN m- 1), and have excellent self-cleaning property. Furthermore, by adjusting the manufacturing process parameters, different superamphiphobic surfaces with adjustable droplet adhesion can be manufactured easily. Overall, this study provides a simple way for obtaining the superamphiphobic surfaces on metal substrates, and verified their potential application fields for self-cleaning, oil droplet manipulation and oilbased microreactor engineering.

Inspired by the biomimetic design of entropy-stabilized flexible connections in icosahedral virus capsids, this study presents an innovative strategy for the design of high-performance heterogeneous metal interfaces using the high-entropy effect. A high-entropy interface is developed using a gradient laser power control strategy in the laser-directed energy deposition (LDED) process, successfully constructing a 316L stainless steel/FeCoCrNiMn high-entropy alloy (HEA) heterogeneous structure. Multi-scale characterization indicated that the material was dominated by a stable FCC solid-solution structure. The gradient transition at the interface was confirmed by the spatial distribution and variation trends of the constituent elements. Electron backscatter diffraction (EBSD) analysis demonstrated complex microstructural evolution mechanisms influenced by the high-entropy effect, contributing to the strengthening of the heterogeneous metal system. Mechanical testing results showed that the flexible interface enabled the material to maintain an ultimate tensile strength of 638 MPa and an elongation of 37.5%. Furthermore, tribological testing reveals improved wear resistance, with a specific wear rate of 4.81 & times; 10-5 mm3/N & sdot;m under a 10 N load, outperforming both 316L and HEA individually. This work not only provides a biomimetic, innovative solution to overcoming interface challenges in heterogeneous materials but also highlights the significant potential of the high-entropy effect in cross-scale interface engineering.

Inspired by the erosion-resistant dorsal armor of the desert scorpion, this study developed biomimetic ZTA ceramic composites with enhanced resistance to solid particle erosion. Three biomimetic configurations, namely convex-bump (CH-O), convex-curved-surface (CH-CS), and convex hybrid rigid–flexible (CH-HS) structures, were fabricated by direct ink writing (DIW) 3D printing. Their erosion performance was evaluated by gas–solid two-phase erosion tests at impact angles ranging from 15° to 90°, and the underlying mechanisms were elucidated through erosion morphology analysis, actual impact angle analysis, and stress-wave propagation analysis. The results showed that the erosion rate of all samples first increased and then decreased with increasing impact angle, reaching a maximum at around 60°. Compared with the smooth control sample, CH-O exhibited lower erosion resistance under low-angle erosion conditions but showed clear improvement under high-angle erosion conditions, with the erosion resistance increased by 18.39–32.54%. CH-CS further improved the erosion resistance of CH-O, with enhancements of 14.31–53.92% at low impact angles and 24.57–35.17% at high impact angles. Among all the biomimetic designs, CH-HS exhibited the best overall erosion resistance, showing an additional improvement of 9.22–32.16% over CH-CS across the tested impact angle range. The superior erosion resistance was attributed to the synergistic effects of convex-bump morphology, curved-surface-induced particle deflection, and rigid–flexible coupling. These biomimetic features modified the actual impact angle of the particles, deflected their trajectories, reduced direct particle impact, and generated a shadow effect, while the flexible layer dissipated impact energy through reflection unloading at the rigid–flexible interface. This study provides a novel strategy for the biomimetic design of erosion-resistant ceramic composites and offers new insights into mitigating erosion damage in ceramic-based mechanical components.

Ti–12Mo–6Zr–2Fe (TMZF) alloy, characterized by its low elastic modulus and high strength-to-weight ratio, is a promising candidate for biomedical implants. However, its application in biomedical fields remains limited due to an incomplete understanding of the corrosion and tribological synergism in simulated body fluid (SBF). This study systematically investigates the phase composition, microstructural evolution, and biocorrosion and tribology behaviors of laser powder bed fusion (LPBF) fabricated TMZF alloys before and after solution treatment (ST). The optimal LPBF parameter was achieved at a linear laser energy density of 200 J/m, resulting in a relative density of 99.96

In this article, an innovative stepping piezoelectric actuator driven by friction differential force was proposed. The differential piezoelectric actuator consists of three parallel shafts (two driving shafts and one guiding shaft), two of which can move axially under the action of piezoelectric stacks. Specific voltage signals were used to excite sequential movement of the driving shafts, thereby generating a frictional force difference on a mover. The friction differential force can be used to push the mover to move in a stepping manner along the guiding shaft, which eliminates the adverse effect of the clamping mechanism and reduces parasitic displacement. The primary load-bearing component was analyzed using the finite element method and the operational principle of the differential piezoelectric actuator was clarified by constructing a dynamic model. A prototype was manufactured, and an experimental platform was established. The experimental findings demonstrated that the differential actuator attained a resolution of 36 nm and a peak velocity of 1.019 mm/s. Under a consistent driving voltage of 150 V and a driving frequency of 1 Hz, the maximum load capacity was measured to be 300 N. Moreover, the parasitic displacement observed in the differential actuator prototype was +/- 0.119 mu m.

During the healing process of skin wounds, there are challenges such as slow tissue regeneration and bacterial infections. This paper has developed a drug-loaded composite hydrogel dressing that can promote angiogenesis, inhibit bacteria, and reduce inflammation. The hydrogel is composed of gelatin (Gel) and acrylamide (AM), and is formed into a biomimetic cell membrane structure through cross-linking. By adding different concentrations of graphene oxide (GO), the tensile strength of the hydrogel dressing can be significantly increased (from 57.54 KPa to 95 KPa), and the adhesion strength (shear strength) can be effectively enhanced (16.44 KPa). Additionally, Panax ginsenoside Rh1 has been successfully encapsulated in the hydrogel, achieving local controlled release. In vivo evaluation shows that the enhanced matrix by graphene oxide and the sustained release of Panax ginsenoside Rh1 have an antibacterial rate of up to 98.69% against S. aureus. It also stimulates the proliferation, migration, and tube formation of endothelial cells, thereby achieving strong vascularization at the wound site. Moreover, it can enhance the secretion capacity of anti-inflammatory factors (IL-4 from 19.54 to 105.61 pg/mL, IL-10 from 151.94 to 339.98 pg/mL), thereby accelerating the wound healing process. This hydrogel dressing provides a promising strategy for achieving high-quality wound repair.

ABSTRACT In this paper, the resin films were selected as energy directors, and the influence of flat energy director thickness and welding time on the ultrasonic welding joints of GF‐PPS composites was investigated. The ultrasonic welding termination condition was set to time‐control mode in order to analyze the influence of energy director thickness on the interface formation. The viscoelastic heat generation and interfacial temperature distribution of energy directors with different thicknesses during the welding process were analyzed using COMSOL software and a thermocouple. The interface and defect formation mechanisms were analyzed by examining the macro and microstructural characterization of the joint cross‐section. The lap shear strength of joints under different welding parameters was evaluated through single lap shear tests, while the fracture mechanisms were analyzed using a scanning electron microscope. Furthermore, these findings can be extended to other types of composites, which provide valuable insights for improving the ultrasonic welding process of thermoplastic composites.

Miniature piezoelectric robots (MPRs) have become a hotspot in robotics research due to their characteristics of compact structure, agile movement, and low power consumption. However, achieving a high payload-to-weight ratio while maintaining miniaturization and balanced output of other key performances remains a challenge. Therefore, a novel miniature bipedal piezoelectric robot (MBPR) has been proposed to address this challenge. The robot utilizes the cooperative inertia principle of its dual-drive feet to generate cross-scale linear and rotational motion. A prototype measuring 42 x 32 x 11.05 mm3 with a mass of 47.4 g is fabricated and experimentally tested. The results demonstrate that the MBPR achieves highly stable motion output; motion resolutions are 6 nm and 74 nrad; maximum speeds reach 3.26 mm/s and 105.34 mrad/s; maximum payload capacities attain 11 kg and 10 kg, yielding payload-to-weight ratios of 232 and 211, respectively-ratios that far surpass those of existing MPRs. The MBPR also exhibits stable output performance on different supporting surfaces. Furthermore, successful optical fiber alignment has been demonstrated across diverse application scenarios using the MBPR. The exceptional performance characteristics demonstrated by the MBPR indicate substantial potential for diverse applications.