Advanced Engineering Materials最新文献

Triboelectro-Induced Surface Defects

Bioinspired synthetic collagen-like peptide hydrogels offer the advantages of both natural and synthetic biomaterials. In their Research Article (10.1002/adem.202502084), Hong Liang and co-workers show that by combining self-assembly with light-triggered crosslinking, these tunable materials achieve bonding strength comparable to commercial adhesives like LiquiBand. Additionally, their cytocompatibility and biodegradability make them a robust platform for soft tissue repair and wound closure.

This study fabricates AlCoCrFeNb_0.4Ni_2.1 high-entropy alloy (HEA) via vacuum induction melting and systematically investigates how heat treatment duration (0–18 h at 800 °C) regulates its microstructure, tribological performance, and corrosion resistance. The as-cast HEA features a face-centered cubic + body-centered cubic (FCC + BCC) eutectic structure and (Co–Cr–Fe)₂Nb-type Laves phase, with FCC precipitates already existing in the BCC phase. Heat treatment triggers dual precipitation behavior: FCC phases further precipitate in BCC matrices, and Laves phases form in FCC phases, with both precipitate fraction and size increasing with prolonged holding time. This microstructural evolution expands grain boundary spacing, reducing hardness and wear resistance, yet the wear mechanism (synergistic oxidation, adhesion, and abrasive wear) remains unchanged. Strikingly, heat treatment enhances corrosion resistance by promoting passive film formation/repassivation via Nb-rich Laves phases, with the 18 h-treated HEA achieving optimal corrosion performance. Notably, the 2 h-treated HEA retains favorable hardness and wear resistance while lowering the friction coefficient, providing a novel strategy for tailoring HEAs with balanced mechanical and tribological properties.

Oxide-based sodium-ion conductors are gaining renewed interest as solid electrolytes for all-solid-state sodium batteries, owing to their intrinsic safety, chemical stability, and abundance of constituent elements. This review highlights recent progress in key material families: β/β″-alumina, NASICON-type compounds, and Na₅YSi₄O₁₂-type (N5) silicates. NASICON materials have achieved room temperature ionic conductivities approaching ~1 × 10⁻² S cm⁻¹, rivaling those of sulfide-based electrolytes, while maintaining compatibility with cosintering processes. N5-type silicates have also emerged as promising candidates, reaching mid-10⁻³ S cm⁻¹ range at room temperature through compositional tuning and controlled processing. These advances have been complemented by progress in scalable fabrication techniques such as tape casting. Perovskite- and layered-type multifunctional sodium-ion conductors are also being explored. The review further discusses critical design considerations such as electrochemical stability, sinterability, and interfacial compatibility, which are essential for enabling practical all-solid-state battery technologies based on oxide electrolytes.

Additive manufacturing (AM) is revolutionizing the production of polymer-derived ceramics, creating new trends for the design of materials with specific properties and structures. These properties are primarily attributed to their unique amorphous microstructure, which consists of a silica-like network of dispersed silicon carbide (SiC) domains, with a percolating free carbon phase distributed throughout the structure. This unique structure enables precise tuning of mechanical, electrical, and thermal properties. This review presents a critical overview of the integration of AM and silicon oxycarbide (SiOC) materials science, providing a systematic roadmap from precursor chemistry and vat photopolymerization techniques to the fabrication of complex, application-specific devices. The review illustrates how these tailor-made structures translate into revolutionary applications across diverse fields, including aerospace, energy, biomedicine, and sensing. Furthermore, this review highlights major challenges arising from pyrolysis, including shrinkage and scalability, and show how emerging strategies, such as hybrid manufacturing and AI-driven inverse design, can effectively overcome these obstacles. By linking microstructural control to macroscopic performance, this review not only summarizes current knowledge and research but also provides a robust framework for next-generation research and the industrial-scale use of additively manufactured SiOC ceramics.

Triboelectro-Induced Surface Defects

Bioinspired synthetic collagen-like peptide hydrogels offer the advantages of both natural and synthetic biomaterials. In their Research Article (10.1002/adem.202502084), Hong Liang and co-workers show that by combining self-assembly with light-triggered crosslinking, these tunable materials achieve bonding strength comparable to commercial adhesives like LiquiBand. Additionally, their cytocompatibility and biodegradability make them a robust platform for soft tissue repair and wound closure.

ZnO-based thin films are promising antimicrobial coatings, yet their long-term performance and antifungal mechanisms remain poorly understood. This study evaluates the influence of film thickness and metal doping (Ti, Ag) on antifungal performance (R-value according to ISO22196:2011) of ZnO thin films against Candida albicans under dark conditions. Their long-term performance is assessed over repeated uses through direct contact (five cycles of 24 h) and leachate assays (10 cycles of 24 h). The role of reactive oxygen species (ROS) is examined through cellular responses and morphological changes. ZnO thin films exhibit a “slight” (R = 0.7) but persistent (three cycles) effect, inducing intracellular superoxide formation. This oxidative stress is mitigated by peroxidases under nutrient-rich conditions, causing cell wall damage and 20% cell viability. Ti incorporation has no measurable effect. In contrast, Ag doping triggered 99% ROS accumulation, exceeding cellular defenses, causing irreversible damage, and short-lived “very good” activity (R = 7, one cycle). Thicker films maintained activity over more cycles and leachate showed similar effects, suggesting release of antifungal compounds from films’ surface. These results show that intracellular ROS generation drives antifungal activity of ZnO-based films, whereas film thickness determines durability. Understanding these parameters is essential to design antimicrobial coatings capable of reliable performance in real-world applications.

Sheet cracking severely impacts the formability of magnesium alloy sheets during rolling, representing a critical defect that cannot be overlooked. Accurate analysis of plastic anisotropy is essential to reveal the mechanisms behind edge cracking. To predict damage evolution during room-temperature rolling, this study employs a shear-modified anisotropic Gurson–Tvergaard–Needleman (GTN) model, incorporating Zhou's modified GTN model for low stress triaxiality and Hill’48 anisotropic yield criterion, to investigate transverse through-thickness cracks (45° to rolling direction [RD]) under 30% reduction. Using ZK60 magnesium alloy as the research material, mechanical tests with digital image correlation are conducted, and the shear-modified GTN model is integrated into ABAQUS/Explicit via a VUMAT subroutine to calibrate rolling parameters. The results demonstrate that the model accurately predicts the location and morphology of rolling cracks and reveals that ZK60 exhibits significantly lower yield strength in the transverse direction than in the RD, making it more susceptible to shear band initiation under transverse tensile stress. Low stress triaxiality ($��\eta �=�0.2�$) promotes shear damage, causing microvoid coalescence along 45° to form cracks, while high stress triaxiality ($��\eta �=�0.45�$) leads to microvoid expansion. Ultimately, surface shear cracks preferentially propagate through the thickness, forming macroscopic cracks at 45°.

On-demand control of asymmetric surface remains challenging and introduces a barrier for wider applications of asymmetric surface in industrial applications. To tackle this challenge, a new strategy to design reversible asymmetric surface—the asymmetric direction, amplitude, and degree of surface can be reconfigured under external stimuli—is developed by incorporating metamaterial-like structure as a regulation layer beneath the surface of soft material. These structural soft materials are called “metalayer-regulated soft materials” (MRSMs). The critical element of the MRSMs is the metamaterial-like structure that introduces unusual deformation mechanisms to develop asymmetric surface evolution. In this article, wheel-like structure is selected to embedded in the regulation layer to achieve reversible asymmetric surface under progressive compression. Different wheel-like structures—three-spoke, cross-like, and five-spoke—with a group of nondimensional geometrical parameters are systematically studied using a method that integrates computational simulation and experimental testing. The achieved waviness and the degree of asymmetry are ≈25.6% and ≈159.6% higher than those of existing approaches, respectively. Moreover, MRSMs provide wider reversible tunability on waviness and asymmetry. Due to the attractive behaviors of MRSMs, this strategy offers great potential in many applications—e.g., directional liquid transport, oil–water separator, programmable structural adhesive—that will benefit from reversible asymmetric surfaces.

Thermoelectric Modules

In their Research Article (10.1002/adem.202502649), Chul-Ho Lee and co-workers fabricate a thermoelectric power module of MgAgSb/Mg₃(Sb,Bi)₂ with an air-cooled heat exchanger. Lower thermal conductivity leads to a larger temperature difference than that with the Bi₂Te₃ module, resulting in comparable electrical power generation. This result demonstrates that the present module is a promising alternative to the conventional Bi₂Te₃ module that has been the best performing thermoelectric module near room temperature for over a half century.

Thermoelectric energy conversion has attracted notable attention as a promising technology for generating electricity from waste heat. At present, Bi₂Te₃ system is the only material used in commercial thermoelectric modules. Despite extensive research into alternative materials, Bi₂Te₃ has consistently demonstrated the best near room temperature thermoelectric performance for over 50 years. On the other hand, recent studies have identified MgAgSb and Mg₃(Sb,Bi)₂ as high-performance p-type and n-type thermoelectric materials, respectively. Furthermore, MgAgSb/Mg₃(Sb,Bi)₂ modules have been reported to achieve high conversion efficiency. However, these compounds are typically synthesized by ball milling, a process unsuitable for large-scale production. Suitable replacements for Bi₂Te₃ modules must exhibit both high conversion efficiency and have simple synthesis procedures. To fulfill the requirements, a scalable synthesis method for MgAgSb based on melting and annealing is established, without grinding or hot pressing. MgAgSb/Mg₃(Sb,Bi)₂ modules incorporating thus obtained MgAgSb elements generate electrical power comparable to conventional Bi₂Te₃ modules when tested in a system with an air-cooled heat exchanger, reflecting practical application conditions. These results suggest that MgAgSb/Mg₃(Sb,Bi)₂ modules are promising alternatives to commercial Bi₂Te₃ modules.