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To overcome the limited application forms and inadequate therapeutic effects of 3D-printed scaffolds and osteogenic drug carriers. Nonetheless, concerns persist regarding the negative effects of burst and nonsustained release. In this study, we further enhanced the osteoinductive potential of 3D-printed BAG scaffolds by coating them with simvastatin (SIM) and poly(lactic-co-glycolic acid) (PLGA) with sustained release properties. Morphological assessment through SEM revealed evenly coated 3D-printed BAG scaffolds (BAG/PLGA/SIM), which showed sustained SIM release properties in vitro. The SIM released from BAG/PLGA/SIM still exhibited osteogenic activity in the augmentation of ALP activity and mineralization in mesenchymal stem cells. In an animal study of rat calvarial bone defects, both SIM-loaded BAG scaffolds, BAG/PLGA/SIM and BAG/PLGA/5 × SIM, significantly improved bone regeneration. Moreover, the IHC analysis of BMP2 and vWF expression also exhibited significant increases in both SIM-loaded BAG scaffolds. Notably, a higher SIM concentration (BAG/PLGA/5 × SIM) did not outperform a lower SIM concentration (BAG/PLGA/SIM) in promoting new bone formation. In conclusion, BAG/PLGA/SIM scaffolds could provide an excellent 3D architecture with sustained SIM release properties in vitro and excellent osteogenic properties for bone repair in vivo. The drug-loading method on 3D-printed BAG scaffolds could provide an alternative strategy for the development of multifunctional scaffolds for clinical applications.

Small scale (∼1:30–1:40) Reinforced Concrete is useful for centrifuge testing. However, manufacturing the reinforcing cages by hand at this scale is practically difficult. This paper suggests that small scale reinforcement can be manufactured using a metal 3D printer. Mechanical properties of 3D printed submillimeter rebars are discussed and compared to properties of typical prototype rebars. Different model concrete mix designs are tested to identify optimal mixes. Pullout tests of rebars with different surface rib configurations embedded in different concrete mixes are discussed.Based on the test results, by modulating the printing parameters it seems feasible to obtain 3D printed submillimeter bars that can be used as physical models of prototype rebars. A gypsum-based model concrete was more similar to prototype concrete than cement-based mixes. Most importantly, bond slip behavior that is comparable to full-scale concrete could be achieved, something that is vital and has never been reported before.

Developing new materials through traditional trial-and-error is time-consuming and costly due to the vast potential compositions to explore. Moreover, some desirable properties are mutually exclusive, presenting challenges for materials design. Herein, we employed an active learning strategy to address the strength-ductility trade-off in SAC105 lead-free solders. We developed two Gaussian regression models, one for strength and one for elongation representing ductility. The Gaussian Upper Confidence Boundary algorithm, a Bayesian optimization method, was used to balance exploitation and exploration by considering prediction uncertainty. The variance weight was designed to decay with adaptive iterations. The two models were linearly combined and the maximal combined model recommended alloys on the Pareto front for experiments. After just three iterations, a new 91.4Sn-1.0Ag-0.5Cu-1.5Bi-4.4In-0.2Ti low-silver SAC solder was discovered, exhibiting 73.94±5.05 MPa strength and 24.37±5.92% elongation, representing the best comprehensive mechanical properties. Weldability experiments also showed excellent performance. Based on Ab initio molecular dynamics, a precise machine learning potential revealed the alloying mechanism in Sn-In solid solutions with quantum accuracy in systems of over 103 atoms, closely matching experimental X-ray diffraction pattern. To facilitate materials informatics development, all active learning algorithms was made open-source in our designed framework, Bgolearn.

Developing new bio-metallic materials with improved performance has attracted intensive research focus over the last decades. In the present work, a new series of (TiZr)95-xHfxMo5 (x = 0, 10, 15, 20, 25, 31.67) multi-principal elements alloys (MPEAs) have been designed for potential implant materials. The mechanical properties, deformation characteristics, tribological properties, corrosion resistance, and in vitro biocompatibility of the MPEAs were characterized. All the TiZrHfMo alloys possess a high yield strength (913–––1083 MPa) and tensile strength (931–––1118 MPa) and a large microhardness (296–––333 Hv). The addition of Hf into the alloys induced severe lattice distortion, which increased the solid-solution strengthening effect. It also resulted in a finer grain size and led to excellent wear resistance. Meanwhile, the results showed that the dislocation glide mode transformed from planar slip to cross-slip and the transformation became apparent with the decrease of Hf. Also, the MPEAs showed a good corrosion resistance compared to CP-Ti, which was credited to the superior passivation films. The in vitro biocompatibility experiments displayed that the TiZrHfMo alloys exhibited high cell viability ratios, which were close to that of CP-Ti. The present work demonstrates the huge potential of TiZrHfMo MPEAs as implant material for biomedical applications.

Interrupted cooling experiments of FGH97 nickel-based powder metallurgy (PM) superalloy with different cooling rates were carried out using a DIL805A quenching dilatometer. The microstructural evolution of the γ′ precipitates during cooling after solution heat-treatment was investigated by means of field emission scanning electron microscopy (FE-SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Vickers microhardness tests were performed on the samples that were interrupted at different temperatures to establish a relationship between microstructure and mechanical properties. The results revealed that the secondary γ′ precipitates preferentially nucleated at a higher temperature, and gradually grew during the cooling stage. Meanwhile, the morphology of the secondary γ′ precipitates transitioned from spherical to cubic, to rounded cuboidal, to a butterfly-like shape, and ultimately splitting into octo-cubes, whose driving force was attributed to the mutual competition between surface energy and elastic strain energy. During the initial stages of the cooling process, the microhardness decreased due to the growth and coarsening of the secondary γ′ precipitates. As the temperature decreased, the supersaturation within the matrix became sufficient to overcome the energy barrier for a second burst of nucleation, the tertiary γ′ phases precipitated, resulting in an increase in microhardness.

The laser powder bed fusion manufactured Ti-6Al-4V alloy predominantly consists of α' martensite, resulting in excellent strength but limited ductility, hinders widespread application. Therefore, it is crucial to achieve the decomposition of α' martensite and improve the ductility. However, the reverse transformation behavior and its mechanism of the β phase, as well as its stability remain unclear. Our findings demonstrate that the reverse transformation behavior of the β phase follows a diffusion-controlled process. The decomposition of α' martensite into α + β initiates at approximately 550 ℃, while the transformation from α to β phase occurs around 870 ℃. Increasing temperature leads to an increase in reverse-transformed β phase. The retention of these reverse-transformed β phases at room temperature also depends on their stability, which exhibits a significant correlation with V element partitioning. Additionally, this study reveals a critical temperature (840 ℃) at which the maximum volume fraction (18.6 %) of retained β phase is obtained, exhibiting exceptional mechanical properties, particularly the uniform elongation surpassing those observed in an as-printed microstructure of LPBF-ed Ti-6Al-4V alloy.

Road bituminous binders are becoming more complex since, to enhance properties and/or engineer circular economy, the conventional binder is enriched with modifiers of different nature giving birth to a final-product recognisable as highly heterogeneous fluid. The assessment of these materials relies on rheological measurements; however, existing testing equipment are designed for homogeneous fluids, proving to be often inadequate. In fact, rotational testing lacking mixing efficiency during measurements, can compromise sample stability, resulting in non-representative results Lo Presti et al. (2014). To address these challenges, a dual helical ribbons (DHR) was purposefully created and successfully employed in prior studies to measure the rotational viscosity of highly heterogeneous asphalt materials Giancontieri et al. (2019). While the DHR effectiveness has been extensively discussed in earlier investigations, this study aims to contribute to the scientific community at large by providing: state-of-the-art on improving mixing efficiency of highly heterogeneous fluids, rationalizing the choice of the DHR geometry comprehensive technical details for realising any DHR, verified through numerical modelling Calibration with model input parameters achieved by adopting the Rieger and Novak method, and finally design validation. The authors aim for the broader material science community to benefit from this investigation, enabling technologists to independently develop DHR devices and explore new applications.

We present a comprehensive study on the identification of eutectic high entropy alloys (EHEAs) through integration of CALculation of PHAse Diagrams (CALPHAD), machine learning (ML), and experimental data. By performing high-throughput CALPHAD calculations to obtain the temperature differences between liquidus and solidus phases (ΔT) and employing gradient descent optimization to identify local minima in ΔT surface, we obtained a reliable dataset for EHEAs across 5–6 component alloy families, which effectively addresses current limitations in both the quality and availability of EHEA data. In conjunction with literature-based experimental data, this dataset serves as the foundation for ML models trained with an XGBoost classifier. The physical descriptors with the most significant effects on the classification of eutectics and non-eutectics are identified. Our study reveals that configurational entropy alone yields a remarkable 98% classification accuracy, elucidating its dual role in phase stabilization and melting point depression. For the first time, an explicit phase selection rule to identify eutectics has been derived from an artificial neural network model, which facilitates efficiently screening EHEAs without resorting to CALPHAD nor ML models. This study presents a robust, data-driven strategy applicable not only to EHEAs but also to a broader range of alloy systems.

This investigation aimed to design a thermally stable microstructure of an ITER-grade Cu-0.7Cr-0.07Zr alloy. The chosen approach involved employing a novel Equal Channel Angular Pressing (ECAP) at cryogenic temperatures (CT), in which the temperature was strictly controlled, followed by subsequent ageing. Post-ECAP ageing at 400 °C for 15 min resulted in a substantial enhancement in yield strength in CT-processed specimens, with a remarkable increase of 22% in comparison to their pre-aged counterparts. Additionally, ageing under these conditions yielded a more stable microstructure at elevated temperatures, with average grain size variation below to 1 μm. The observed stability was attributed to the formation of fine Cr-rich precipitates during ageing that hinder grain boundary motion, thereby preventing grain growth and potential softening of the CuCrZr alloy. These findings elucidate a promising thermomechanical processing avenue for strengthening microstructures processed by cryogenic severe plastic deformation and/or exposure to elevated temperatures. Finally, the adopted processing route in this study not only facilitated but distinctly culminated in attaining the paramount strength/ductility relationship for CuCrZr alloys with a stable microstructure at medium-to-high temperature range.

We would like to respond to “Comments on Seo et al., Materials & Design 117 (2017) 131–138, https://doi.org/10.1016/j.matdes.2016.12.066″. Mangindaan et al. raised concerns about deriving the 2nd order equations for optimizing the W-pattern CMP slurry compositions. However, we clarify that there were no errors in deriving the 2nd order equations obtained by employing response surface methodology using a face-centered design model.

In this work, a synergistic strategy of small cation substitution and charge compensation to realize efficient red luminescence has been developed, which greatly improves the luminescence performance of Mg2InSbO6:Mn4+ by modulating the degree of distortion of the Mn4+ lattice site. The doping Mn ion is stabilized in the tetravalent state and occupies the Sb5+ site. After the Sc3+-In3+ substitution, the emission characteristic of the original Mg2InSbO6:Mn4+ is regulated and effectively red-shifted, and the extruded [MnO6] octahedron present distorted due to the aberration of the near-neighboring lattice sites of Mn4+. Through the Sc3+-In3+ substitution and Li+ compensation, the optimal thermal stability at 423 K is enhanced by 19.1% compared with that of Mg2InSbO6:Mn4+. Surprisingly, the designed Mg2In0.3Sc0.7SbO6:0.003Mn4+,Li+ phosphor exhibits excellent quantum yield (82.02%) and high color purity (97.3%), which is higher than most of the reported Mn4+-doped phosphors. Moreover, the growth of sweet potatoes by combining the plant growth illumination device encapsulated by the phosphor is implemented. The relevant growth parameters further confirm that the designed phosphors have a great potential application in the field of plant growth lighting.

Lattice structures, one type of mechanical metamaterials, exhibit excellent mechanical properties such as a high strength-to-weight ratio and energy absorption capacity. However, predicting the stress–strain relationship of lattice structures remains a challenge because the mechanical behaviors of additively manufactured lattices are affected by both the structure parameters of a lattice and process conditions. This study proposes a machine learning (ML)-based predictive modeling framework to predict the entire stress–strain curves, compressive modulus, and energy absorption of lattice structures with varying structure and process parameters. Feature engineering techniques are used to transform raw data into new data representations compatible with ML models, including artificial neural networks, long short-term memory (LSTM), and convolutional neural networks (CNN). Two novel feature representations, including polygons and colormaps, are developed to transform structure and process parameters from tabular format into image format for CNN. The LSTM model that predicts stress–strain curves achieves a minimum mean absolute percentage error (MAPE) of 0.147. The CNN (colormap) model achieves a minimum MAPE of 0.174 when predicting compressive modulus. The ANN and LSTM models achieve a minimum MAPE of 0.068 when predicting energy absorption. The training time to build these ML models is less than 6 min.

Research into precipitation hardening in additively manufactured (AM) maraging steel is mainly conducted on the material after several hours of holding at the peak hardening temperatures of 450–500 °C. Lower temperatures are expected to have little to no effect on mechanical properties even after very long holds at these temperatures. This article, however, demonstrates that new precipitates grow and cause a noticeable hardening effect in solution-annealed AM maraging steel after only a 6-hour hold at a temperature of 350 °C. High-resolution scanning and transmission electron microscopy (HRSEM, HRTEM) was used to identify the new precipitates. Very fine coherent microdomains containing mainly nickel and molybdenum layers were found. Particles of a new phase, Al0.5CNi3Ti0.5, were also detected. Additionally, various precipitates were also found in both the as-built and the AM solution-annealed maraging steel samples. Precipitates such as Ni3Ti, Al0.3Ni0.35Ti0.35 and Al2O5Ti, were also observed in the as-built condition. After subsequent solution annealing at 820 °C additional Ni3Mo particles and another type of Ti-rich particles, Ni4Ti3, were further found in the AM steel microstructure. The additional new phases which precipitated during the final hardening at 350 °C caused an 18 % (200 MPa) increase in strength.

Material extrusion additive manufacturing (MEX) gains increasing interest due to its cost-effectiveness. However, concerns arise regarding inherent MEX characteristics potentially affecting mechanical properties. This study investigates the effects of shot peening and heat treatment on MEX 17-4PH stainless steel. After shot peening, surface nanocrystalline and compressive residual stress are induced. Aging results in higher hardness and tensile strength with lower elongation, while shot peening results in higher surface hardness with minimal change in elongation. For fatigue properties of as-sintered specimens, Al2O3 particle contamination dominates at high cycle regimes, while other MEX surface inhomogeneities dominate at low cycle regimes. Furthermore, as-aged properties are dominated by all surface inhomogeneities, resulting in the non-improvement of fatigue performance compared to the as-sintered specimens. However, shot peening on the as-sintered specimens significantly enhances fatigue properties through the formation of surface nanocrystalline structures and the induction of compressive residual stress, albeit with the occurrence of wrapped corners acting as fatigue crack initiation sites. Remarkably, the combination of aging and shot peening yields the most improvement in fatigue performance, exhibiting behaviours akin to as-sintered specimens with shot peening but without the generation of wrapped corners. Instead, fatigue crack initiation sites shift to subsurface region’s inhomogeneities.

This study presents a novel star-shaped honeycomb meta-material (N-SSHM) that realizes improved static mechanical and vibration properties by introducing rings to the four sides of a traditional star-shaped honeycomb meta-material (T-SSHM). Optimization of the static and vibration suppression properties is achieved using the assembly concept. The static properties of the proposed meta-materials are initially investigated using the finite element method (FEM) and static compression tests. The results demonstrate that the N-SSHM exhibits a superior load-bearing capacity compared to the T-SSHM. Subsequently, the vibration properties of the meta-material are studied using simulations and experiments. The wave propagation characteristics of the meta-materials are explored by introducing the phase velocity and group velocity. The study also examines the effects of design parameters (ring size, metal pin size, and pin material) on the bandgap characteristics, and the vibration suppression properties of the meta-material are further enhanced by introducing particle damping. The simulation and experimental results confirm that the proposed N-SSHM has a lower starting frequency and wider bandwidth for the bandgap than the T-SSHM. In summary, the N-SSHM demonstrates significant improvements in both load-bearing and vibration suppression compared to the T-SSHM. This study provides support for the engineering applications of meta-materials.

The effects of Ta alloying on the isothermal oxidation behavior and mechanism of a cast Ti-48Al-3Nb-1.5Ta (at.%) TiAl alloy are investigated. It exhibits excellent oxidation resistance with mass gains of 0.95 and 1.29 mg·cm−2 after 900 °C oxidation for 100/200 h in the air, similar to 8 at.% Nb-containing TiAl alloys. The oxide scale shows a complex multi-layer structure, where the Al2O3 layer and continuous dense nitride layer act as protective layers against diffusion and metal oxidation. The oxidation mechanisms are discussed thermodynamically and kinetically. Compared with Nb, Ta is more significant in inhibiting diffusion and promoting the formation of the protective continuous nitride layer, thus being more effective in improving the oxidation resistance of cast TiAl alloy. Consequently, without considering the influence of microstructure, the oxidation resistance of cast Nb-containing TiAl alloy can be further improved by replacing some Nb with a small amount of Ta. It is supposed to provide new insights into the design of oxidation-resistant TiAl alloys.

Rheumatoid arthritis (RA) is a complex autoimmune disease associated with synovial inflammation and articular cartilage destruction. Currently, high-efficiency low-toxicity management of this intractable disease is highly urgent. Here, a drug-backboned polymer, polyglycyrrhetinic acid (PGA), was synthesized through the condensation of GA, a principal anti-inflammatory component of Glycyrrhiza glabra. PGA was then used as a therapeutic polyprodrug carrier to fabricate carrier-free PGA@Cel nanoparticles (NPs) for treating rheumatoid arthritis. The as-prepared NPs exhibited a uniformly spherical morphology with an average particle size of approximately 180 nm and a celastrol (Cel) loading capacity of around 4.5 %. Upon intravenous injection, the NPs demonstrated prolonged blood circulation, efficient accumulation at inflammatory joints through extravasation via leaky vasculature and subsequent inflammatory cell-mediated sequestration (ELVIS) effect. The present study demonstrated enhanced anti-inflammatory and rheumatic decay efficiency in rat models of antigen-induced arthritis, while simultaneously minimizing off-target toxicity. Overall, our results elucidate that this carrier-free drug-backboned nanopolydrug platform provides a promising strategy for RA therapy.

Lattice structures are featured by their extraordinary mechanical performances in specific stiffness, specific strength, energy absorption, and sound absorption, etc. The recent trend of multifunctionality in engineering applications has raised new requirements for the integration of their mechanical and acoustic properties. In this paper, a multifunctional hybrid plate lattice structure denoted as SBHP is proposed by hybridizing the traditional body-centered cubic plate (BCCP) and simple cubic plate (SCP) lattice structures, and its acoustic and energy absorption properties are investigated by theoretical modeling, simulation analysis and experimental verification. The effects of hole diameters and plate thicknesses on the sound absorption performance are investigated by impedance matching and system damping state analysis. The results show that the average sound absorption coefficient of SBHP-1 is increased by 24% and 62%, and the normalized half-absorption bandwidth is enlarged by 45% and 89% than those of BCCP and SCP, respectively. Heterogeneous lattice structures constructed by using the synergistic mechanism of strong and weak coupling have a more outstanding broadband sound absorption effect. This work provides an effective approach for the design of multifunctional lightweight structures with excellent broadband sound absorption and high energy absorption.

Facing the current lack of clarity in temperature selection mechanisms for warm rolling in medium Mn steel, three warm rolling methods were conducted in 3Mn steel according to the rolling temperatures in the dual-phases region or ferrite region. Subsequently, the effect of heat treatment on the austenite morphologies and tensile properties of warm-rolling samples was studied. Rolling in dual-phase regions (750 °C) led to heterogeneous austenite morphology composed of equiaxed and lamellar grains while rolling in the ferrite region (600 °C) resulted in significant cementite precipitation and the absence of retained austenite. Warm rolling promoted the formation of dislocation cells in the lath-like grains, and they did not evolve into grain boundaries completely because low deformation temperature didn’t trigger the complete dynamic recrystallization. Tempering after rolling provided a significant enhancement in plasticity through the enrichment of C and Mn in austenite and the formation of multiple heterogeneous austenite morphologies with equiaxed, coarse lath-like and fine lamellar grains. In addition, superlattice structures in the matrix are formed through the formation of stacking fault networks and the spinodal decomposition. Ultimately, the exceptional properties were achieved in 3Mn steel, with an ultimate tensile strength of 1409 MPa and a total elongation of 27.3 %.

The application of pressure-sensitive adhesives (PSAs) in transdermal drug delivery systems (TDDSs) is limited. Insufficient cohesion in TDDS can lead to cold flow, patch displacement, dose inaccuracies, and the ‘dark ring’ phenomenon. To address these issues, we developed a semi-interpenetrating network (semi-IPN) PSA using a 2-hydroxyethylacrylate-modified acrylic copolymer as the linear polymer and poly[tri(propylene glycol) diacrylate] as the cross-linked network. Semi-IPN PSAs have better mechanical properties compared to traditional PSAs. The cohesion of the semi-IPN PSA was 31 times and 1.6 times that of commercially available DURO-TAK®87-2287 and DURO-TAK® 87–4098, respectively, and the cold flow of the semi-IPN PSA was significantly reduced. Furthermore, the semi-IPN PSA adhered to the human forearm for longer time and did not exhibit the ‘dark ring’ phenomenon after removal. When loaded with flurbiprofen, the semi-IPN PSA was found to maintain high levels of drug release and skin permeation amount, and flurbiprofen loading did not affect its superior cohesive performance. In conclusion, the innovative application of the semi-IPN PSA for TDDS showed excellent mechanical properties, effective adhesion to the skin without irritation, and highly effective drug release. These findings indicate that the use of the semi-IPN is both simple and highly effective for TDDS.

The formation conditions of lacy ferrite in austenitic stainless steels solidified with primary ferrite was clarified through crystallography in order to increase the amount of lacy ferrite which contributed to the improvement of properties. Lacy ferrite was formed when the misorientation between ferrite and austenite from the Kurdjumov–Sachs (K-S) relationship was ≤ 7° on the close-packed plane and ≤ 9° in the close-packed direction during solidification. In contrast, vermicular ferrite was formed if the misorientation exceeded these values. The temperature gradient during solidification was controlled unidirectionally by two-pass laser welding. Following the performance of two-pass welding with a highly unidirectional laser, it was confirmed that the formation ratio of lacy ferrite to total ferrite significantly increased in the second-pass weld metal by remelting the first-pass weld metal, in which the heat flow direction and preferential growth direction of ferrite and austenite were controlled to be almost parallel. The growth ratio while maintaining the K-S relationship established between ferrite and austenite in the first-pass weld metal, and/or the ferrite formation ratio that satisfies the K-S relationship, increased in the second-pass weld metal because the growth of both the primary ferrite and secondary austenite was crystallographically independent of each other during solidification.

Many tissues and cells are influenced by mechano-electric stimulation, thus the application of piezoelectric materials has recently received considerable attention in tissue engineering. This report investigated electrospun fiber meshes based on poly(vinylidenefluoride-co-trifluoroethylene) [P(VDF-TrFE)] as instructive biomaterials for osteogenic differentiation of human mesenchymal stromal cells (hMSCs). The influence played by methyl ethyl ketone (MEK), used as a solvent in place of dimethylformamide (DMF)/acetone mixture, and the effect of rotating velocity of the electrospinning collector on fiber morphology, mechanical and piezoelectric properties were studied. The solvent had noticeable effects on morphology and piezoelectric properties of electrospun fibers, with MEK outperforming DMF/acetone. By increasing the collector velocity up to 4000 rpm, the fiber diameter reduced and the mutual alignment of the fibers increased, corresponding to enhanced mechanical properties and piezo-active β-phase content. However, as a consequence of the diverse mechanical properties of random and aligned fibrous architectures, which ultimately affected the piezoelectric properties, randomly-oriented fibers exhibited higher remnant piezoelectric properties (Vout and d31 piezoelectric coefficient) than aligned ones. On these scaffolds, hMSCs showed an excellent capability of early osteogenic differentiation, leading to high calcium production. Fiber surface topology, fiber mesh morphology and remnant piezoelectric properties played a determinant role on hMSC osteogenic commitment.

Hemostatic materials that allow fast and convenient hemostasis are urgently needed. However, obtaining an ideal hemostatic agent that exhibits biocompatibility, biodegradability, and hemostatic efficacy remains challenging. Recent studies demonstrate that morphological characteristics of hemostatic materials impact their efficacy. This study reports on the importance of morphological modification of traditional Chinese medicine plant polysaccharides. The hemostatic properties of Three-leaf Qing polysaccharides, optimized in particle (SYQ-P) and sponge (SYQ-S) forms, were investigated in vitro and in vivo. SYQ-S and SYQ-P exhibit excellent biodegradability and biocompatibility, thereby improving fibroblast cell proliferation. The hemostatic mechanism involves stable blood clot formation through intrinsic coagulation pathways. In a lethal mouse liver defect bleeding model, blood loss and clotting time were lower with polysaccharides use than with commercial hemostatic drugs. SYQ-S demonstrates instant water-triggered expansion and high absorption capacity, while the sponge-like morphological characteristics effectively improve blood component concentrations. With efficient hemostasis and excellent biocompatibility, SYQ-S dramatically accelerated wound healing in a full-thickness skin defect model in vivo. Thus, SYQ-S effectively promotes the formation of granulation tissue, collagen deposition, and angiogenesis, which ultimately accelerates wound healing. Our work highlights the design of natural Chinese medicine polysaccharides and presents a promising hemostatic agent for widespread clinical application.

MAB phases (MABs) are atomically-thin laminates of ceramic/metallic-like layers, having made a breakthrough in the development of 2D materials. Though offering a vast chemical and phase space, relatively few MABs have been synthesised. To guide experiments, we perform high-throughput ab initio screening of MABs that combine group 4–7 transition metals (M); Al, Si, Ga, Ge, or In (A); and boron (B) focusing on their phase stability trends and mechanical properties. Considering the 1:1:1, 2:1:1, 2:1:2, 3:1:2, 3:1:3, and 3:1:4 M:A:B ratios and 10 phase prototypes, synthesisability of a single-phase compound for each elemental combination is estimated through formation energy spectra of competing dynamically stable MABs. Based on the volumetric proximity of energetically-close phases, we identify systems in which volume-changing deformations may facilitate transformation toughening. Subsequently, chemistry- and phase-structure-related trends in the elastic stiffness and ductility are predicted using elastic-constants-based descriptors. The analysis of directional Cauchy pressures and Young's moduli allows comparing mechanical response parallel and normal to M–B/A layers. The suggested promising MABs include Nb3AlB4, Cr2SiB2, Mn2SiB2 or the already synthesised MoAlB.

A novel auxetic structure-based stiffener for stainless steel–carbon reinforced polymer (CFRP) T-joints with outstanding strength and toughness improvement is proposed. The stiffener was composed of a bulk web and re-entrant structure flange that was 3D printed using a selective laser melting 3D printer. The stiffener was bonded to a CFRP skin, and a pull-off test was performed to evaluate the pull-off strength, stiffness, and toughness of the joint. The results demonstrated that the proposed structure has specific strength and toughness that were 3.4 and 77 times greater than those of the baseline joint, respectively. The improvement in strength was due to the delayed damage initiation caused by the mismatch between the bending stiffness of the bulk web and the stiffener under the first re-entrant structure. However, the damage initiation in the baseline joint was located at the stiffener edge. Moreover, the negative Poisson's ratio of the re-entrant structure arrested the delamination growth after damage initiation, which enhances the toughness of the joint. By optimizing the structure of the stiffener, a joint with 2.66 and 38.2 times larger specific strengths and toughness compared to the baseline joint with the same specific stiffness was achieved.

Periodontitis, a common chronic inflammatory disease, is characterized by T cell responses leading to gradual alveolar bone loss and eventual tooth mobility or loss. Herein, polylysine-derived carbon quantum dots (PLL-CQDs) are synthesized via the pyrolysis method to facilitate the recovery of periodontal bone loss induced by periodontitis by modulating T cell phenotype. The PLL-CQDs, characterized by small particle size (2.31 ± 0.70 nm) and fluorescence properties, preserved the positive charge of PLL, affirming successful preparation. In vitro studies revealed that PLL-CQDs significantly increased T cell proliferation in a concentration-dependent manner, while effectively suppressing differentiation into CD4+ phenotype. Furthermore, they promoted alkaline phosphatase expression and calcium nodule formation in MC3T3-E1 cells, indicating potential for periodontal bone regeneration. In vivo experiments demonstrated that PLL-CQDs mitigated alveolar bone resorption and modulated periodontal tissue inflammation. Overall, PLL-CQDs exhibited the ability to regulate T cell differentiation and expedite periodontal bone healing, offering promising implications for periodontitis treatment and suggesting novel strategies for addressing immune-associated bone diseases using CQDs.

Like many pixel-based additive manufacturing (AM) techniques, digital light processing (DLP) based vat photopolymerization faces the challenge that the square pixel based processing strategy can lead to zigzag edges especially when feature sizes come close to single-pixel levels. Introducing greyscale pixels has been a strategy to smoothen such edges, but it is a challenging task to understand which of the many permutations of projected pixels would give the optimal 3D printing performance. To address this challenge, a novel data acquisition strategy based on machine learning (ML) principles is proposed, and a training routine is implemented to reproduce the smallest shape of an intended 3D printed object. Through this approach, a chessboard patterning strategy is developed along with an automated data refining and augmentation workflow, demonstrating its efficiency and effectiveness by reducing the deviation by around 30%.

Intelligent nanodrug delivery systems that respond to tumor microenvironment have been extensively utilized in cancer therapy research. However, the passive diffusion of prodrug nanoparticles is hindered due to the absence of capillaries and dense extracellular matrix in the tumor microenvironment, resulting in low efficiency of anti-tumor drug delivery. In this study, we developed a metal matrix proteinase 2 (MMP2) and glutathione (GSH) responsive Janus prodrug nanoassemblies targeted towards tumors. The Janus prodrug nanoassemblies consist of targeted micelles and prodrug nanoaggregates linked by click chemistry. The size of the nanoassemblies can be reduced within the tumor microenvironment of high concentrations of MMP2. Active targeting and size shrinkage synergistically enhance cell uptake efficiency and tumor penetration capacity of nanoassemblies. The release of camptothecin (CPT) occurs in a GSH-dependent manner, while under irradiation with 660-nm red light, the photosensitizer introduced in the prodrug generates reactive oxygen species (ROS) to induce tumor cell death. Fluorescence imaging results demonstrate enhanced tumor targeting capabilities of Janus prodrug assemblies. As a theranostic agent for tumors, Janus prodrug assemblies achieve desirable synergistic chemotherapy and photodynamic therapy for colon cancer treatment. This work would provide a novel strategy for cancer diagnosis and treatment.

Among numerous polluting compounds, the organic dyes and antibiotics are two servious factors causing water pollution. Hence, it is urgent to find a fast and safe way to degrade waste water in a sustainable approach. Here, ferroelectric heterostructure based on 2D Bi2MoO6 nanosheets and Bi2S3 nanorods has been prepared by a two-step solvothermal method for the reduction of organic dyes and antibiotics. Due to the energy band balance between Bi2S3 and Bi2MoO6, the formed type-II heterostructure can populate charge transfer at the junction and effectively inhibit electron-hole recombination. Under ultrasonic stimulation, catalytic active sites of a Bi2MoO6/Bi2S3 heterostructure for pollutant degradation can be generated through rapid charge transfer activation, thus enhancing the catalytic degradation effect of organic dyes and antibiotics. The Bi2MoO6/Bi2S3 heterostructure not only has good degradation effect, but also shows better stability. This work opens up new avenues for designing highly-efficient catalysts, which is of importance for wastewater degradation and energy-saving applications.

Additive manufacturing of Ti-6Al-4V alloy via laser powder-bed fusion leads to non-equilibrium α′ martensitic microstructures, with high strength but poor ductility and toughness. These properties may be modified by heat treatments, whereby the α′ phase decomposes into equilibrium α+β structures, while possibly conserving microstructural features and length scales of the α′ lath structure. Here, we combine experimental and computational methods to explore the kinetics of martensite decomposition. Experiments rely on in-situ characterisation (electron microscopy and diffraction) during multi-step heat treatment from 400∘C up to the alloy β-transus temperature (995∘C). Computational simulations rely on an experimentally-informed computationally-efficient phase-field model. Experiments confirmed that as-built microstructures were fully composed of martensitic α′ laths. During martensite decomposition, nucleation of the β phase occurs primarily along α′ lath boundaries, with traces of β nucleation along crystalline defects. Phase-field results, using electron backscatter diffraction maps of as-built microstructures as initial conditions, are compared directly with in-situ characterisation data. Experiments and simulations confirmed that, while full decomposition into stable α+β phases may be complete at 650∘C provided sufficient annealing time, visible morphological evolution of the microstructure was only observed for T≥700∘C, without modification of the prior-β grain structure.

Bioinspired, bistable snap-through structures are promising to release a burst of mechanical energy transformed from chemical energy, stored, and released incrementally during swelling/deswelling. Thin, disk-like hopper can harness the inhomogeneous deswelling to create the required constraint and flexible snap-through part. Here, hoppers composed of a single type of polydimethylsiloxane (PDMS) or concentric PDMS rimmed by a stiffer PDMS are cast into precisely micromachined molds. The mechanical properties and swelling/deswelling behavior of the constraining rim and flexible snap-through materials, in concert, allow a superior specific power of 1782 W kg−1, specific energy of 4.44 J kg−1 for a jump up to 321 mm, outperforming many more complex implementations. The jump benefits from an improved storage modulus ratio and a lower swell of the rim to the snap-through center part, which enhanced the confinement and elastic energy storage. A sharp spatial gradient in volume change between the two materials during deswelling, tunable by the porosity of the rim materials, enhances the jumping by allowing more material to store and release elastic energy, revealed by the strain analysis with 3D-digital image correlation. The illustrated multimaterials and porous materials strategies can promote the development of integrated energy harvesting and actuation for soft robotics.

The rise of additive manufacturing (AM) has positioned lattice infilling as a pivotal strategy for creating lightweight, customized engineering components. This study presents a generative method that enables the conformal design and stiffness prediction of complex gradient strut-node lattice structures. A stress-driven Multi-Agent System (MAS) is introduced for the parametric optimization of lattice material distribution, incorporating geometric limitations, stress factors, and AM constraints. A beam element model simplifies the numerical analysis of the structure linear stiffness. By applying the Response Surface Method (RSM), a numerical model is established, not only conducting a quantitative analysis on the sensitivity of MAS design variables but predicting mechanical performance. This method is validated by designing a supporting component, demonstrating that the optimized lattice design can achieve a linear stiffness 1.4 times greater than that of conventional uniform lattice infills for the same mass. This research provides a comprehensive framework for the efficient design and analysis of irregular lattice structures at a macroscopic scale.

The joining of Inconel 625 and GRCop42 using additive manufacturing is required for thermal management of high operating temperature components such as rocket combustion chambers. Though prior efforts have been made to use laser directed energy deposition to join these materials, the impact of laser power and deposition sequence on microstructure of these joints is not well understood. In this study, Inconel 625 onto GRCop42 and GRCop42 onto Inconel 625 joints are fabricated by powder directed-energy-deposition at various laser powers and subsequently subjected to characterization in terms of present defects, grain morphology, and phases. Results show lack-of-fusion free Inconel 625 onto GRCop42 joints can be fabricated by increasing the laser power in the first layer. Substrate remelting in GRCop42 onto Inconel 625 joints is found to result in a melt pool composition which induces liquid-state immiscibility, resulting in a Cu-deprived liquid solidifying to form crack prone islands. Increasing laser power decreases the embrittlement of these islands due to the precipitation of a lower volume fraction of intermetallic phases.

Effective treatment of infected diabetic wound (IDW) requires delivering therapeutic agents to both wound surface and deep layers, as well as improving the wound microenvironment through antibacterial actions, clearing excessive reactive oxygen species (ROS), and promoting vascular regeneration. Here, we present a novel inorganic nanosheet called MnO2/PDA@Cu, consisting of manganese dioxide (MnO2) with copper (Cu) ions loaded on its surface through in-situ polymerization, using polydopamine (PDA) as an intermediate. We then encapsulated the MnO2/PDA@Cu nanosheet into a methacrylated hyaluronic acid (HA) soluble microneedle patch, creating a photodynamic-controllable multifunctional MnO2/PDA@Cu-HA microneedle. We used this microneedle to treat IDWs in a rat full-thickness skin defect model. Results demonstrated that the MnO2/PDA@Cu-HA microneedle effectively delivered therapeutic agents to both wound surface and deep layers, where PDA's photodynamic therapy swiftly combated bacteria under 808 nm near-infrared irradiation. Simultaneously, MnO2 acted as a nanoenzyme, mitigating ROS levels and providing oxygen for wound healing. In addition, the photothermal effect of PDA further facilitated the release of Cu, promoting vascularization. The MnO2/PDA@Cu-HA microneedle significantly accelerated wound closure, re-epithelialization, and collagen deposition, enhancing IDW healing. In conclusion, our synthesized MnO2/PDA@Cu-HA microneedle represents a photodynamic-controllable multifunctional platform for IDW treatment, offering a promising approach for effective wound management.

Background: Hydrogel carrying exosomes shows better prospects for bone regeneration. Objective: This work investigated the effect of cross-linking N-succinyl chitosan-oxidated hyaluronic acid-based hydrogel loaded with bone marrow mesenchymal stem cell-derived exosomes on bone regeneration in cranial defects. Methods: Cross-linking N-succinyl chitosan-oxidated hyaluronic acid-based hydrogel loaded with bone marrow mesenchymal stem cell-derived exosomes was prepared, and utilized to treat bone marrow mesenchymal stem cells, human umbilical vein endothelial cells, and rats with cranial defects. Logical experiments were implemented to research the effect of the prepared hydrogel on osteogenesis and angiogenesis of cells in vitro, and on bone regeneration in rats with cranial defects. Results: Cross-linking N-succinyl chitosan-oxidated hyaluronic acid-based hydrogel loaded with bone marrow mesenchymal stem cell-derived exosomes showed good biocompatibility and self-healing property. It promoted osteogenic differentiation of bone marrow mesenchymal stem cells and angiogenesis of human umbilical vein endothelial cells, and facilitated osteogenic differentiation, angiogenesis and bone regeneration in rats with cranial defects. Conclusion: Cross-linking N-succinyl chitosan-oxidated hyaluronic acid-based hydrogel loaded with bone marrow mesenchymal stem cell-derived exosomes facilitated osteogenesis, angiogenesis and bone regeneration in rats with cranial defects. It might be an effective strategy for inducing bone regeneration in individuals with cranial defects.

Inspired by “crimped” collagen fiber, which induce a low-level load region within the hierarchical structures of ligaments and tendons, this study introduces a braiding technology aiming at characterizing nonlinear mechanical behavior. Samples of the developed artificial ligament with a multilayer braided structure were fabricated and tested. Alterations in the number of braiding layers, wales, and courses significantly affect the mechanical properties of the artificial ligaments. Specifically, the toe length exhibited an increase of up to 104.58 %, while the linear stiffness exhibited variations concomitant with changes in these parameters. Additionally, a mathematical model to describe the relationship between the toe length and linear stiffness was developed based on the braiding parameters and material properties of the fibers. Alternative fibers were employed and tested to demonstrate a consistency with the mathematical model. The correlation coefficients were calculated as 0.9644 for the toe length and 0.9203 for the linear stiffness. Lastly, this study mimics the mechanical behavior of the human medial collateral ligament (MCL) by integrating the artificial ligament into a bio-fidelity knee model with a joint stiffness of 1.77 Nm/deg, resulting in a high degree of similarity with human knee in valgus-varus, further affirming the utility and applicability of this study.

Continuous fiber-reinforced silicon carbide composites have received significant attention due to their high-temperature mechanical stability. However, their widespread implementation has been hindered by intricate fracture mechanisms and limited toughness. This study presents a real-time approach for identifying damage type in 2.5D SiCf/SiC composites and highlights the significant impact of minor eccentric loading angle on the fracture behavior and mechanical properties using acoustic emission (AE). Even a slight degree of eccentric loading angle can significantly alter the fracture behaviors, leading to a significant increase in fracture toughness. The fracture damage evolution law of 2.5D SiCf/SiC under varying eccentric loading angles was investigated with the help of the AE damage identification, fracture morphology and finite element analysis. These findings provide valuable insights for multi-axis stress analysis of 2.5D high-performance composites.

A two-dimensional (2-D) multi-phase cellular automaton (CA)-finite difference (FD)-lattice Boltzmann (LB) coupled model is developed to simulate the hydrogen pore formation during dendritic and eutectic solidification of hypoeutectic Al-Si alloys. In this model, the dendrite and eutectic structures are simulated using a CA technique. The solute diffusion is solved by the FD method. The nucleation, growth, and motion behavior of gas pore, and hydrogen transport are simulated by a LB Shen-Chen scheme. It is found that the pores can grow fully but compete in the primary dendrite growth stage. Conversely, pores newly nucleated in residual inter-dendrite liquid during the eutectic solidification stage grow restrictedly and independently. Pore shape severely deformed by the compression of the surrounding solid structures. Moreover, the effects of the initial Si composition, initial hydrogen concentration and cooling rate on the pore formation are qualitatively and quantitatively studied. It is found that the initial Si composition significantly impacts on the pore size and distribution, but little effect on the porosity percentage which decreases markedly with the decreasing initial hydrogen concentration and increasing cooling rate. Comparison reveals that the simulated microstructure morphological characteristics and the predicted porosity percentage agree well with the experimental observation reported in the literature.

Osteoporosis, closely related to age, is characterized by impaired bone mass and bone strength, damage of bone microstructure, resulting in a higher risk of fractures with minimal trauma, especially in the hip and spine. Quercetin (Que), a natural compound, has previously demonstrated its potential anti-osteoporosis effects via promoting bone formation and anti-bone resorption. However, Que is poor water solubility, lack of bone targeting, and requires high concentration to exert its therapeutic effects. In this work, a pH-responsive and bone-targeted nanomedicine HCCP-Que-PEG-ALN (HQPA) was developed via using hexachlorocyclotriphosphazene (HCCP) as the cross-linkage, Que, alendronate (ALN), and amino-polyethylene glycol (NH2-PEG) as other building blocks. We demonstrated that HQPA can form spherical nanoparticles in aqueous solution with average size of 158.3 ± 59.8 nm with high drug loading capacity of Que (31.4 w/w%) and obvious bone-targeting capability. in vitro experimental results indicated that HQPA NPs have dual anti-osteoporosis effects of promoting osteoblasts and inhibiting osteoclasts. Furthermore, HQPA NPs can effectively reduce the bone loss in OVX mice with low toxicity to major organs. We believe that this method should be a general and useful route for fabrication of bone-targeted natural-compounds-based nanomedicines for treatment different bone-related diseases.

Osteoarthritis (OA) is characterized by cartilage degradation, inflammatory responses, and osteophyte formation. Matrix metalloproteinase 13 (MMP13) is a hallmark of OA development, and increased MMP13 expression is closely associated with extracellular matrix degradation. MMP13 expression varies significantly at different stages of OA progression. While cyclooxygenase 2 (COX-2) inhibitors are commonly used to treat OA, their long-term systemic administration increases the risks of adverse effects. Therefore, with the aim of achieving localized and responsive delivery of the COX-2 inhibitor celecoxib, the current study investigated an innovative MMP13-responsive micro-nano hydrogel microsphere system. Celecoxib-loaded cationic liposomes are non-covalently attached within the microsphere, enabling controlled drug release for OA treatment. In an OA environment with elevated MMP13 expression, the system is degraded via the action of MMP13 substrate peptide (MMP13sp), facilitating accelerated release of drug-loaded liposomes to improve the inflammatory microenvironment and treat OA rapidly. Compared to a phosphate-buffered saline solution with hyaluronidase (HAase), the prepared hyaluronic acid methacrylate microspheres HAMA/MMP13sp/Lipo@celecoxib exhibited rapid degradation in a solution containing a physiological concentration of MMP13/HAase, demonstrating specific enzyme responsiveness for precise anti-inflammatory drug release. The MMP13-responsive hydrogel microsphere system achieves intelligent and controllable drug release in OA, effectively decelerating disease progression and promoting articular cartilage repair.

This study illustrated the impact of Saponins in electrospun nanofibers on nerve regeneration and compared them with Tween 80, which is commonly used as a synthetic surfactant. The study explores the effect of Saponins, natural emulsifiers known for their effectiveness in forming and stabilizing emulsions. Surfactant choice is crucial due to its effects on fluid stability, influenced by parameters like polymer concentration, homogenization rate, and surfactant type/amount. This study explored PCL as the core and PVA as the shell.Core/shell scaffolds displayed favorable wettability (contact angle: 67.0° ± 1.3) and improved mechanical properties (wet state tensile strength: PVA 1.1 ± 0.2 MPa, PVA/PCL-Saponin 2.0 ± 0.5 MPa). The MTT viability assay demonstrated higher viability of PC12 cells on Saponin-containing nanofibers (85.0 % ± 0.1) compared to Tween 80 (69.0 % ± 0.1) after 24 h. Subcutaneous implantation in rats showed no significant inflammation after one week. Eventually, in the animal model, the conduit containing Saponin was more effective than Tween 80 in repairing the rat's sciatic nerve within six weeks, as evidenced by NF-200 counts and histological studies. Overall, the study indicates that PVA/PCL-Saponin nanofibers, without requiring Saponin surfactant removal, show high quality and effectiveness for tissue engineering and medical purposes.

Most traditional powder melting-based additive manufacturing (AM) technologies generally yield high-performance parts at the expense of additional cost and energy consumption. As an economical and efficient alternative method, material extrusion (ME) that deploys polymer-based filaments with highly filled metal particles offers the possibility of scalable, low-cost fabrication of metal components. As a critical step, sintering governs the mechanical strength and geometry of the final parts. The grain growth behavior induced during sintering should be well controlled to achieve the parts with the desired mechanical performance. Due to the nature of AM, grain growth kinetics could also involve extremely complex grain boundary migration and atomic diffusion mechanisms caused by the heterogeneous pore distribution. In this work, an analytical model was developed to predict and understand the grain growth behavior of stainless steel (SS) 316L built by ME-based sintering-assisted AM. Such a model accounts for anisotropic viscosity parameters calibrated through a three-dimensional dilatometry test, enabling the prediction of grain size evolution during sintering. Grain growth kinetic parameters were further identified by the grain size data at the heating and holding stages. To validate and generalize the model, we also conducted the grain size evolution prediction under different sintering temperature profiles for as-built SS 316L specimens. This work will provide scientific insights into the grain growth behavior of metal parts built by this AM technique and its understanding can be readily transferred to other sintering-assisted AM processes like binder jetting and ink writing for metal structure creation.

Friction rolling additive manufacturing (FRAM) is a solid-state additive manufacturing method capable of accommodating a wide range of material forms. However, there is a lack of comprehensive research on the optimal feedstock form. Thus, this study investigated the influence of feedstock shape on material formation, microstructure, and mechanical properties. The results revealed that irrespective of whether a strip or wire was used, the plasticized material flowed through a thin plastic flow channel (approximately 112 μm) between the tool head and the feedstock. Wire feedstock resulted in greater deformation and more significant grain refinement than strip feedstock, with grain refinements of 95 % and 81 %, respectively. Additionally, gaps between multiple wires were filled with plasticized material, forming a dense and defect-free mixing zone. Moreover, the tensile performances of the deposited samples obtained from wire and strip feedstocks exhibited no significant differences, measuring 143.9 MPa and 144.5 MPa, respectively. Numerical simulations were employed to elucidate the underlying mechanism of the temperature field and material flow behavior when strips and wires were used as feed materials. The findings of this study are anticipated to serve as a reference for selecting feedstock forms for FRAM.

Manufacture-induced defects are a critical issue in composites applications that result in high volumes of material waste and costly experimental trials to help mitigate this. Advances in process modelling techniques have enabled the prediction of defects. However, the high computational cost of these tools limits their usefulness in an industrial context as they often struggle with the ever-increasing size of industrial structures, and present significant challenges to undertaking large optimisation problems. In this work, a recently proposed homogenisation scheme is used to accurately simulate the autoclave processing of a composite part of industrial complexity in a fraction of the time of other state-of-the-art processes. Physical manufacture of a demonstrator part is used to evaluate the model in terms of accuracy. Based on the observed good agreement (discrepancy of less than 1.5% in the thicker sections and less than 7% in the thinner region of the part), a data-driven optimisation of the part’s caul plate has been conducted that aims to mitigate defects whilst keeping cost and material use low. Further manufacturing trials validate the proposed framework by demonstrating successful defect elimination and a 25% improvement in the maximum local deviation from ideal design.

Voxel modeling is a technique in which an object is represented by an array of cubes. One advantage in design-for-manufacturing is that selected voxels may be assigned desired responsive properties through additive manufacturing. It allows for achieving reversible shape transformation in soft responsive self-repairing solids within a strategic sequence. The first step in the sequence involves selecting an equivalent geometric shape. The second step involves mapping shapes to preserve properties during continuous deformation. The third step involves transforming the shape from one form to another. The fourth step involves defining changes in dimensions. The final step involves correlating the flow of stress with the stretch of the solid. This research also considers self-repair or self-healing as part of the transformation process because the splitting or joining of solids involves continuous deformation. The newly transformed shape can also be considered as the intermediate shape, or first shape for next transformation. This leads to a chain of shapes that are topologically equivalent, and interchangeable. The iterative steps involved in shape transformation finds applications in topology optimization, generative design, metastructures, among others. One application of shape transformation in these domains is that it serves as an alternative to material reduction techniques.

Metal additive manufacturing is associated with thermal cycles of high rates of heating, melting, cooling, and solidification. Some areas within the build experience thermal cycles that depend on the paths of the energy source. Additionally, geometrical features, such as thin walls and overhangs, can lead to heat accumulation, potentially affecting the microstructure, fatigue life, and induced residual stresses that may lead to dimensional distortion and cracking. The identification of significant heat accumulation can be used for part quality monitoring to inform the design process, enhance the quality of printed parts, and optimize the process parameters. This study aims to efficiently identify heat accumulation with affordable in-situ infrared imaging for further characterization and mitigation to enhance the quality of printed parts. A computational framework employing machine learning is developed to identify zones of local heat accumulation in real time. The effectiveness of this approach is demonstrated by experiments conducted on a build with a wide variety of geometrical features. In addition, characterization and detailed analyses of detected local heat accumulation zones are provided.

The investigation of fracture and fragmentation is essential for evaluating the protection performance and structural design of ceramic armour. This paper focused on the dynamic failure and fracture mechanisms of the fine-grained Al2O3/SiC composite subjected to plane shock waves. The macroscopic shock response characteristic was determined through a series of plane impact tests, which included the Hugoniot curves of the composite. The results indicated that the fracture mechanism is significantly influenced by specific stress characteristics. The transgranular fracture in large grains and intergranular fracture in small grains exhibit obvious local plastic deformation characteristics. Moreover, the presence of second-phase SiC particles markedly influences both crack propagation and the microfracture mode of the composite. Lastly, a statistical analysis of the ceramic fragments was conducted after the soft recovery of specimens in impact experiments, and analytical models were developed and modified to predict the distribution of fragments under plane shock loading.

A novel design for hierarchical-porous acoustic metamaterials (HPAM) is proposed to enhance the functionality of Helmholtz-type resonators and porous materials, achieving continuous and efficient broadband sound absorption. This method can potentially eliminate absorption valley and improve the coupling strength through a synergistic energy dissipation mechanism and hybrid impedance matching behavior. Excellent sound-absorbing capability of the elaborately crafted HPAM was demonstrated analytically, numerically, and experimentally. Specifically, the results revealed an impressive average absorption coefficient of 0.77, with 73 % of the α points exceeding 0.8 across the entire test frequency range. Furthermore, the sound absorption of HPAM can be further optimized to attain ultra-broadband properties by modifying the hierarchical configuration and composite design of the porous materials. The physical mechanism is revealed through the integration of the hierarchical scaling effect and the energy-trapped mode. Numerical simulations revealed the emergence of three distinct absorption peaks at frequencies of 0.76, 1.4, and 3.6 kHz, respectively, and the effective absorption spectrum exceeded 3.4 kHz. Overall, the proposed design highlights the role of hierarchical structures and porous materials in synthesizing superior sound-absorbing properties that fully elucidate the relationship between structure and performance, and provide an avenue for potential noise-control applications.