Achieving synergistic enhancement of strength, plasticity, and heat resistance remains a major challenge for titanium matrix composites. In this study, a beta TRIPLEX heat treatment (beta 3HT) process was adopted to tailor the matrix microstructure of (TiB + La2O3)/IMI834 composite, achieving a synergistic improvement in both room-temperature strength-plasticity and high-temperature strength. EBSD and HRTEM analyses revealed that the second stage alpha + beta solution coarsened the primary alpha lamellae within acicular structure formed during the first stage beta solution, while the final annealing promoted uniform silicide precipitation. Furthermore, beta 3HT enhanced the alpha-variant selection effect of TiB, promoting the formation of coherent or semi-coherent TiB/alpha interfaces, with their fraction increasing from 2.3 % to 22.5 %. Compared with untreated-TMCs, the treated composite retained similar room-temperature strength (1222 +/- 1 MPa vs. 1215 +/- 4 MPa) but showed higher uniform ductility, with uniform elongation rising 91 % (3.5 % +/- 0.5 % to 6.7 % +/- 0.2 %). The high-temperature strength rose nearly 15 %, reaching 860 +/- 4 MPa at 600 degrees C, 757 +/- 4 MPa at 650 degrees C, and 625 +/- 2 MPa at 700 degrees C. This strength improvement arose from the synergistic effects of dislocation pinning by the lamellar microstructure, silicide precipitation strengthening, and load-transfer by TiB.

Loss of toughness in titanium matrix composites (TMCs) is often inevitable, as strength enhancement typically comes at the expense of ductility, especially for brittle ceramic reinforcements induced by interfacial chemical reaction. To fully exploit the strengthening potential of nanocarbons in TMCs and maintain ductility, it is critical to mitigate the in-situ reactions between nanocarbons and titanium. This study proposes an inspired strategy by reinforcing Ti-6Al-4V (Ti64) matrix with graphene oxide (GO) decorated with Fe3O4 nanocrystals (Fe3O4@GO/Ti64). This design achieves 41.6% improvement in toughness, with simultaneously enhanced strength and elongation, compared to that of Ti64 alloy. Uniform Fe3O4 coatings (similar to 20 nm) were distributed on the GO surface and subsequently consumed during consolidation via reaction with the Ti matrix, thereby preserving GO. Microstructural analysis of plastic deformation revealed that elongation was primarily attributed to the dislocation slip bands, grain boundary sliding and twins, while the in-situ TiC inhibited slip-band motion. The estimated strengthening factors illustrated that solid-solution strengthening dominated the enhanced strength in all composites. Furthermore, the Fe3O4@GO/Ti64 composites exhibited significantly enhanced load transfer effects compared with GO/Ti64, due to the Fe3O4 modificative coatings. These findings underscore the crucial role of interfacial decoration and solid-solution mechanisms in improving the overall mechanical performance of the TMCs, while also highlighting their economic and environmental potential in lightweight metallic design.

In this study, we synthesized ECP@nB via an in situ solvothermal method using three energetic coordination polymers (ECPs) and nano boron (nB). This method leverages interfacial interactions between different ECPs and nB to produce composites with diverse morphologies. Subsequently, through a series of experimental characterizations, we further verified the effects of different interactions on the thermal properties and combustion behavior under laser ignition. The results indicate that, due to the different size, nB primarily adsorbs onto the micro-scale Cu/CoECP surface via adsorption, whereas nB and nanoscale NiECP form an ordered layered structure due to greater interfacial contact between particles. Thermal analysis results indicate that, compared to nB, the total heat release of all ECP@nB samples was increased, with CuECP@nB and CoECP@nB showing increases of 73% and 50%, respectively. Furthermore, the combustion of ECPs releases a large amount of gas, which disperses nB and B2O3 agglomerates through physical action, thereby promoting contact between nB and the surrounding oxygen. At the same time, the metal or metal oxide products of ECPs react with nB or B2O3 under high temperature, resulting in a 59.3–60.2% reduction in the combustion time of ECP@nB, while the maximum flame area increased by 5–10 times. This strategy provides a new approach to regulating the performance of boron-based energetic materials by leveraging the synergistic effects of chemical reactions and physical processes to enhance combustion efficiency while suppressing the agglomeration of condensation-phase products.

Achieving a synergistic improvement in flame retardancy and mechanical performance remains a persistent challenge in intumescent flame-retardant (IFR) polypropylene (PP) systems. Previous studies have predominantly focused on optimizing flame retardant formulations while largely overlooking the critical role of polymer matrix chain architecture in determining the overall composite performance. In this work, three PP matrices with distinct chain architectures-homopolymer (hPP), random copolymer (rPP), and block copolymer (bPP)-were systematically investigated within an identical IFR formulation. The results reveal a dominant role of chain architecture in differentiating flame retardancy and mechanical performance, which are governed by distinct structural factors, namely melt rheological behavior and phase morphology. Specifically, bPP exhibits superior flame retardancy, as evidenced by a higher limiting oxygen index (LOI) and improved UL 94 rating, which may be associated with its higher melt viscosity and resistance to dripping during combustion. In contrast, rPP shows significantly improved mechanical performance, owing to its more homogeneous phase structure and enhanced chain mobility. These findings demonstrate that flame retardancy and mechanical properties can be effectively tuned through different structural pathways, providing a viable strategy to mitigate the conventional trade-off in IFR systems. This work highlights the importance of polymer chain architecture as a complementary design parameter alongside flame retardant additives for developing high-performance PP composites.

The excellent adhesion and chemical corrosion resistance of epoxy resin (EP) are widely used in the field of materials. However, the problems of its flammability and mechanical loss after modification urgently need to be solved. Here, the D@M nanosheets prepared by coating the surface of MXene with DHPPC allow the EP to achieve the effects of both fire safety and mechanical enhancement. The EP nanocomposites can reach the V-0 level at 1 wt % addition, the oxygen index is as high as 29.8%, and the charring is rapid and dense. The peak heat release rate (pHRR), CO, and CO2 production rate values are reduced by 31.20, 45.41, and 37.57%, respectively. The fire and smoke suppression effect is excellent. In addition, the mechanical properties of EP nanocomposites were enhanced due to the uniform dispersion of nanosheets and the two-dimensional structure of the nanosheets. The tensile strength and flexural strength were, respectively, increased by 32.9 and 12.4% with the addition of 1.5 wt %. The polymer coated on the surface of the nanosheet increases the viscosity of the nanocomposite itself and shows good adhesion in the face of different common plates. The bonding strength of the steel can even reach 13.53 MPa. It provides an efficient and practical solution for the realization of multifunctional EP nanocomposites with mechanical enhancement, fire safety, and strong bonding.

Organic chemiresistors have been widely investigated in recent years due to their high sensitivity and excellent robustness (time-stability, compatibility, selectivity, and batch-to-batch reproductivity). However, in the pursuit of high sensitivity, compromising the response and recovery ability of these chemiresistors were often inevitable. Here, we propose an unperceived method to enhance the sensitivity of ion-in-conjugation (IIC) materials through the isotope effect, achieved by partial deuteration of the interaction sites. The fabricated sensor after deuteration achieves about four-fold enhancement of sensitivity at the parts-per-billion (ppb) level in detecting trace nitric dioxide (NO2), while maintains its response/recovery ability. Linear fittings of the extracted sensitivity denote that the deuteration does not alter the adsorption models. Combining the theoretical calculation and the measurements with in-situ infrared spectroscopy and the resonant microcantilever (RMC), the interaction site of the dual hydrogen bonding (DHB) is proven. This strategy highlights that the effectiveness of isotope effect on improving the sensory performances in chemiresisitors and may expand more applications to other semiconductor devices.

Flexible polyurethane foams are widely used in building and vehicle interiors due to their lightweight and high resilience. However, most foams are non-biodegradable or fireproof, leading to serious white foam pollution and safety problems. Here, FPUF made of a porous MOF material loaded with flame retardant elements as a coating is reported, which realizes fire protection, isolation of heat and noise, and recovery of foam. The results show that FPUF-3 exhibited excellent fire and smoke suppression effects, and PHRR, CO production, and CO2 production are reduced by 28.5%, 54.5%, and 21.4%, respectively. The FPUF-3 shows a longer heat preservation effect and can reduce the common noise decibel by >35%. In addition, the coating exhibits excellent stability under extreme acid-base conditions and has longer durability and effectiveness under alkaline conditions. Furthermore, the separation and recovery of FPUF and coating can be realized by ethanol solvent, and the recovery rate of coating can reach >80%, the foam still has the original high elasticity and lightweight characteristics. It provides a sustainable and practical solution for effectively improving the noise reduction, fire prevention, and heat insulation capabilities of FPUF.

As joint bending deformation is a primary feature of biological motions, measuring the joint angle variations of human is crucial, especially due to its significant spatial coordinate transformation and highly variable effective strain distribution across the section. The coupled deformation mode and the remarkable strain make the precious monitor of the joint motion challenging. In this study, we designed a monolithic flexible sensor with bi-side laser-induced graphene (BS-LIG) with a decoupling capability for tension and bending deformation modes. The sensor featured a PDMS substrate with sensing units on both surfaces can eliminate the contribution of tensile strain of the neural plane on the sensing value by utilizing the difference of the two-strain data, offering a reliable data in feedbacking the value of the real-time joint angle. Benefiting from the inherent softness and stretchability of PDMS, the BS-LIG sensor can withstand a tension of over 45

We prepared a titanium matrix composite (TMC) with added boron nitride nanosheets (BNNSs) for strengthductility trade-off issues. The composite, characterized by in-situ nano-TiB intragranular distribution and trace nitrogen solid solution, was prepared using rapid hot press sintering (FHP) and short-duration hot rolling. During pre-rolling heat preservation, the diffusion of boron and nitrogen resulted in the intragranular distribution of nano-TiB and nitrogen solid solution. The nano-TiB demonstrated excellent load transfer, fracture suppression, and dislocation storage capabilities at both room and high temperatures. Coupled with the nitrogen solid solution, the composite exhibited a significant enhancement in strain hardening effect compared to the titanium matrix. The composite outperformed the titanium matrix in strength and ductility at both room and high temperatures, demonstrating a notable strength-ductility synergy. This work provides a reference for designing TMCs with excellent performance at both room and high temperatures.

Due to the large geometric deformation capacity of curved beams, they are frequently employed as critical components in superstructure design and stretchable electronic technology. However, there is still a lack of an efficient method for monitoring and inverting the global deformation behavior of such structures under unknown loading conditions. In this study, the LIG-based customized strain sensors are used to capture the local strains of the curved beam structure. A finite deformation theory-based inversion framework is developed to reconstruct the large geometric deformation by correlating discrete strain measurements with the finite deformation analysis of the curved beams. This approach enables rapid inversion for the finite deformation of the curved beams under uniaxial tensile loads, and its validity has been confirmed by comparing with the experimental deformation results. The demonstration of global deformation inversion of lattice structures shows that this method provides direct and effective guidance for the design and optimization of mechanical metamaterial and stretchable electronic devices.

Shearography is a non-destructive defect detection technique that, when combined with neural networks, can efficiently and accurately detect near-surface defects in composite materials. However, the high cost of the dataset significantly limits the application of neural networks in shearography. Current simulation data generation techniques fail to eliminate the discrepancies between simulated and experimental data, resulting in suboptimal performance when training neural networks with only simulated data. To address this issue, this paper utilizes phase map sequences measured by shearography as the medium for defect detection and designs a YOWO_SS3D spatiotemporal object detection network. The network simultaneously learns both the spatial distribution features and temporal variation patterns of simulated phase map sequences, achieving high-accuracy detection of defects. The experimental results show that, with only 4000 frames of simulated data for training, our network achieved a detection accuracy of 96.99% on experimental phase maps, which is considerably higher than the 65.37% accuracy achieved by training the YOLOv4 network with the same simulated data. Using our technique, only pre-generated simulation data are required to train the network, enabling YOWO_SS3D to be directly deployed for practical defect detection tasks. This approach eliminates the substantial costs associated with collecting experimental training data and promotes the application of neural network technology in the shearography field.

Active metamaterials with specific deformation responses present great promise in fields such as multifunctional antennas, stretchable electronic devices and reconfigurable soft robots, due to their ability to switch between different operational states within a single system. However, the previous researches on active metamaterials with shear deformation responses exhibit two issues: inability to further enhance the shear deformation magnitude of the active metamaterials and inability to achieve precise customized design of the metamaterials, such as realizing simple shear deformation. Moreover, the inverse design of active metamaterials is challenging because theoretical models describing the finite deformation of active metamaterials under external-field actuation are lacking. To address the aforementioned issues, this study reports a design strategy for the electrothermally actuated lattice metamaterials to realize remarkable shear deformation with the maximum shear angle exceeding 26 degrees and the capability to precisely achieve desired mechanical responses of the active metamaterials. The shear angle of the electrothermally actuated lattice metamaterials reported in this paper has increased by approximately 82 % compared to that achieved in previous studies. Theoretical models for the electrothermally actuated metamaterials are established to describe the shear deformation behaviors. The theoretical models are demonstrated through both qualitative and quantitative comparisons with finite element analyses (FEAs) and experimental results. Theoretical models provide detailed predictions of the configuration after electric heating and offer analytical solutions for crucial mechanical quantities, such as the effective strains and shear angle for the electrothermally actuated lattice metamaterials exhibiting shear deformations. Moreover, experimental results and FEA calculations show that the simple shear deformation mode can be realized in the active metamaterials through the design strategies proposed in this paper, while it cannot be achieved in previous researches. This demonstrates the capability of the design strategies proposed in this paper to precisely realize required mechanical responses of the active metamaterials.

Lattice tensile strain generated during the preparation of perovskite thin films has detrimental effects on the efficiency and stability of perovskite solar cells (PSCs). Herein, an additive with a conjugated structure, 2,2 ' diamino-[1,1 '-biphenyl]-4,4 '-dicarboxylic acid (DBDA), containing amino and carboxyl groups was introduced to convert tensile strain to compressive strain in perovskite films. The amino and carboxyl groups of DBDA interacted with the main components of perovskite precursors (PbI2 and FAI). These interactions slowed perovskite crystallization, enabling the formation of large grains, passivating defects in perovskite films, transform tensile strain of perovskite films into compressive strain and thus improving the performance and stability of the resulting PSCs. The champion power conversion efficiency of the DBDA-treated PSCs increased to 24.57 %, and 19.66 % for the module with an active area of 14 cm2. Furthermore, the DBDA-treated PSCs remained 92 % of its initial efficiency after 1000 h of continuous illumination. This work provides a new method for regulating lattice strain to prepare efficient and stable PSCs.

For the purpose of achieving boron nitride nanosheets (BNNSs) intrinsic strengthening and relating microscopic interface characteristics to macroscopic mechanical behavior in BNNSSs/Ti composites, the BNNSs/Ti composites were fabricated by field-assisted hot pressing (FHP) and subsequent 923K, 1023K, 1123K or 1223K hot-rolling (HR). Herein, we succeeded in simultaneously maintaining the BNNSs intrinsic structure and considerable interfacial nano-sized TiBw. Interestingly, the superior tensile property (UTS: 1166MPa, El. 9.3%) was realized in 1123K as-rolled BNNSs/Ti composite, whereas the dramatic ductility deterioration exhibited in composite when the HR temperature setting at 1223K. BNNSs load transfer and interface failure behavior were investigated by direct in-situ tensile SEM observation. The nano-TiBw on partially reacted BNNSs played a predominant role on BNNSs load-transfer efficiency and contributed to the desirable ductility. These findings highlighted the untapped potential for improving mechanical properties in BNNSs reinforced metal matrix composite.

Interfaces are crucial factors in perovskite solar cells (PSCs), determining carrier separation, transport, collection, and recombination. The buried interface shows serious defects that are challenging to address directly, thus attracting researchers' attention. This study reveals that the buried interface not only impacts device performance due to defects but also affects the adhesion strength of perovskite on the substrate, which is detrimental to the stable operation of PSCs. To address the dual challenges caused by the buried interface, the strategy of preburying co-component molecules has been proposed. By peeling off the perovskite film samples based on the preburying strategy, it is found that the interface adhesion strength is significantly enhanced, even surpassing the strength of the perovskite bulk phase. Furthermore, the passivation of interface defects and optimization of energy level alignment are achieved, attributed to the change of the interface state, resulting in an effective reduction in non-radiative recombination losses and an obvious enhancement in the extraction and transport of interface charge carriers. Based on this strategy, the device performance achieved a significant improvement. Unpackaged devices maintained over 90 % of their initial efficiency after being stored for 2000 h at 20 % RH. The pre-buried co-component molecular strategy provides a novel approach for constructing robust buried interfaces, offering potential guidance for the advancement of interface engineering in high-performance PSCs.

Suppressing Sn2+ oxidation and rationally controlling the crystallization process of tin-lead perovskite (Sn-Pb PVK) films by suitable bonding methods have emerged as key approaches to achieving efficient and stable Sn-Pb perovskite solar cells (PSCs). Herein, the chelating coordination is performed at the top and bottom interfaces of Sn-Pb PVK films. The chelation strength is stronger toward Sn2+ than Pb2+ by introducing oligomeric proanthocyanidins (OPC) at the bottom interface. This difference in chelation strength resulted in a spontaneous gradient distribution of Sn/Pb within the perovskite layer during crystallization, particularly enhancing the enrichment of Sn2+ at the bottom interface and facilitating the extraction and separation of photogenerated charge carriers in PSCs. Simultaneously, this top-down distribution of gradually increasing Sn content slowed down the crystallization rate of Sn-Pb PVK films, forming higher-quality films. On the top interface of the PVK, trifluoroacetamidine (TFA) was used to inhibit the generation of iodine vacancies (VI) through chelating with surface-uncoordinated Pb2+/Sn2+, further passivating defects while suppressing the oxidation of Sn2+. Ultimately, the PSCs with simultaneous chelation at both top and bottom interfaces achieved a power conversion efficiency (PCE) of 23.31% and an open-circuit voltage (VOC) exceeding 0.90 V. The stability of unencapsulated target devices in different environments also improved.

Abnormal secretion and dysrhythmias of cortisol (CORT) are associated with various diseases such as sleep disorders, depression, and chronic fatigue. Wearable devices are a cutting-edge technology for point-of-care detection and dynamic monitoring of CORT with inspiring convenience. Herein, we developed a minimally invasive skin-worn device with the advanced integration of both interstitial fluid (ISF) sampling and target molecule sensing for simultaneous detection of CORT via a microneedle-based sensor with high sensitivity, excellent efficiency, and outstanding reproducibility. In the microneedle patch, swellable hydrogel was employed as the adsorption matrix for ISF extraction. Meanwhile, europium metal-organic frameworks (Eu-MOF) wrapped in the matrix played a vital role in CORT recognition and quantitative analysis. The wearable and label-free Eu-MOF-loaded microneedle patch exhibited high sensitivity in CORT detection with the detection limit reaching 10(-9) M and excellent selectivity. Molecular dynamics simulation-driven mechanism exploration revealed that the strong interface interaction promoted fluorescence quenching of Eu-MOF. Moreover, in vitro and in vivo investigation confirmed the feasibility and reliability of the sensing method, and excellent biocompatibility was validated. Overall, a sensitive approach based on the wearable Eu-MOF microneedle (MN) patch was established for the simultaneous detection of CORT via visible fluorescence quenching with exciting clinical-translational ability.

The biological system realizes the unity of action and perception through the muscle tissue and nervous system. Correspondingly, artificial soft actuators realize the unity of sensing and actuating functions in a single functional material, which will have tremendous potential for developing intelligent and bionic soft robotics. This paper reports the design of a laser-induced graphene (LIG) electrothermal actuator with self-sensing capability. LIG, a functional material formed by a one-step direct-write lasing procedure under ambient air, is used as electrothermal conversion materials and piezoresistive sensing materials. By transferring LIG to a flexible silicone substrate, the design ability of the LIG-based actuator unit is enriched, along with an effectively improved sensing sensitivity. Through the integration of different types of well-designed LIG-based actuator units, the transformations from multidimensional precursors to 2D and 3D structures are realized. According to the piezoresistive effect of the LIG units during the deformation process, the visual synchronous deformation state feedback of the LIG-based actuator is proposed. The multimodal crawling soft robotics and the switchable electromagnetic shielding cloak serve as the demonstrations of the self-sensing LIG-based actuator, showing the advantage of the design in remote control of the soft robot without relying on the assistance of visual devices. Drawing inspiration from muscle tissue, a self-sensing actuator featuring a 2-in-1 design concept is developed. laser-induced graphene (LIG) is used as both an electrothermal conversion material and a piezoresistive sensing material to develop the somatosensory actuator. Actuators equipped with proprioceptors can autonomously monitor their operational status, obviating the dependence on visual devices.image

High quality tin-lead perovskite solar cells (Sn─Pb PSCs) can be fabricated via simple solution processing methods. However, the instability of precursor solutions and their narrow usage windows still pose challenges in manufacturing efficient and reproducible Sn─Pb PSCs, hindering the commercialization of PSCs. Fluorine tin (SnF2) is widely used as an antioxidant to improve the crystallinity of perovskite. In this study, another role of SnF2 as a stabilizer is found to restrain the deprotonation of methylammonium iodide (MAI) in the precursor solution, which improves their stability and expands their usage windows. Due to the inhibition of SnF2 on oxidation and deprotonation, stable large-sized colloidal clusters form gradually in perovskite precursor solution during aging, leading to uniform nucleation/crystallization during film growth, significantly reducing the roughness and defect density in the films. Because of the competitive deprotonation and oxidation process of Sn2+, the benefit of larger cluster maximizes after about ten days storage of precursor solution. The champion efficiency of Sn─Pb PSCs prepared with 10 days aged precursor solution is 22.00%. High performance of devices fabricated with precursor solution stored for even ≈40 days discloses the wide usage windows of precursor solution with SnF2 additive.

The flammability of epoxy resins and knowing how to achieve curing are particularly important factors during use. A novel approach for enhancing the fire resistance and reducing the smoke emission of epoxy resin during the curing process is suggested, which involves the utilization of a three-source integrated polymerization intumescent flame-retardant. In this study, the synthesis of poly 4,4-diaminodiphenylsulfone spirocyclic pentaerythritol bisphosphonate (PCS) is achieved through using solution polymerization, utilizing 4,4′-diaminodiphenylsulfone (DDS) and spirocyclic pentaerythritol bisphosphorate disphosphoryl chloride (SPDPC) as initial components. Following that, the EP underwent the inclusion of PCS to examine its resistance to heat, its ability to prevent flames, its effectiveness in reducing smoke and its curing effect. Compared to the unmodified epoxy resin, the addition of PCS can not only cure the epoxy resin, but also decompose before the epoxy resin and has a good carbonization effect. With the addition of 7 wt.% PCS, the LOI value can achieve 31.2% and successfully pass the UL-94 test with a V-0 rating. Moreover, the cone calorimeter experiment demonstrated a noteworthy decline of 59.7% in the maximum heat release rate (pHRR), 63.7% in overall heat release (THR), and 42.3% in total smoke generation (TSP). Based on the examination of TG-FTIR and SEM findings, there is ample evidence to suggest that PCS, functioning as a phosphorus-nitrogen intumescent flame-retardant that combines three origins, has the potential to exhibit a favorable flame-retardant impact in both its gas and condensed phases.