This study provides novel insights into the influence of additive manufacturing (AM)-induced grain texture on the solidification behavior of AgCuZnSn filler metal during brazing—a phenomenon not previously reported. The AM surface was shown to affect the crystallographic orientation of the filler metal, suggesting that control over AM texture can be used to tailor the properties of brazed joints. Systematic characterization of the joint microstructure was carried out using SEM, EDS, and EBSD techniques.

AM enables the fabrication of complex geometries, but the limited part size often necessitates joining. Brazing is a suitable method for this, though further study is required to understand the interactions between AM surfaces and filler metals. In this work, AM 316L stainless steel tiles were brazed to machined SS316L cylinders using an AgCuZnSn filler metal. Variables included flux type and filler metal quantity.

Microstructural characterization focused on grain size and orientation in the joint region, particularly at the interfaces between the filler and the two different base materials. All samples exhibited porosity at the filler–cylinder interface. Two main phases were identified in the filler: a Cu-rich and an Ag-rich phase, with the Cu-rich phase forming globular structures at the AM tile interface. Notably, grain structures differed between the two interfaces.

The sample brazed with MetaBraze LT 21 showed similar crystallographic orientation in the filler and AM base metal, suggesting a more isotropic response during deformation. These findings indicate that controlling AM-induced texture could serve as a strategy to engineer the microstructure and performance of brazed joints.

Fabricating bimetallic structures (BmSs) to reduce weight and improve performance has challenges in automobile, infrastructure, and aerospace applications. This study investigates the effect of heat input, Q_H, on interfacial properties of three different wire-arc additive manufacturing (WAAM)-based BmSs, SS316L-SS308L, EN31–AA4043, and SS316L–In718, through microstructural and mechanical characterisations. The value 250-400 J/mm is the determined heat input range for SS-SS and SS-Inconel, and for steel–aluminium, the range is 35-60 J/mm. At the interface of SS316L-SS308L BmS, both the austenitic (γ) and delta-ferrite (δ-Fe) phases formed. The higher tensile strength and elongation reached 591 MPa and 37.2 %, respectively, at an optimum Q_H of 330 J/mm, as the composition of the interface was close to the mirror composition with filler wire. While the average micro-hardness achieved at the interface is 248.3 HV, due to δ-α phases, the interface hardness is enhanced. But for the SS316L–In718 interface, the formation of IMCs (FeNi and FeNi₃) is proportionally influenced by the variation in Q_H. The SEM-EDX analysis demonstrated the enhancement of interface thickness (IT) and elongation while tensile stress was reduced (optimum: 542 MPa) with increasing Q_H. The average micro-hardness value reduced (194.7 to 174.6 HV) with increasing QH due to the coarse grain structure. Conversely, the optimum Q_H was achieved at 43.55 J/mm for the EN31-Al4043 interface, and the SEM and XRD analyses revealed the brittle binary (Fe-Al) and ternary (Al-Fe-Si) IMC formations at the interface. Under optimal conditions, minimal IT (<4 µm), considerable tensile strength (73.2 MPa), very little elongation (~0.9%), and an average micro-hardness value of 128.1 HV were achieved. This analysis highlights heat input as a crucial factor for developing tailored BmSs using WAAM as it controls interface properties. To develop a multi-material high-performance structure, process parameters should be optimized.

This study investigates the effects of localized high-energy laser irradiation on polyimide film, as part of a broader effort to develop crystalline silicon–carbon protective coatings on flexible polymer substrates.

The aim of the study was to determine the optimal laser operating conditions, including wavelength, power, beam speed, and frequency modulation, in order to select the best parameters for subsequent crystallization of the material onto the substrate while minimizing damage to the polymer substrate. Polyimide PMA-40 film (40 μm thick) was irradiated using a Ytterbium pulsed fiber laser (λ = 1064 nm, maximum power = 20 W, pulse energy = 1 mJ). Several processing regimes were tested, varying key parameters such as laser power (%), beam travel speed (mm/s), modulation frequency (kHz), and the number of passes.

Significant surface modification and localized swelling were observed under Modes 1 (1 pass, 50% power, 50 mm/s, 40 kHz), 2 (1 pass, 100% power, 100 mm/s, 40 kHz), and 3 (1 pass, 50% power, 75 mm/s, 100 kHz). These conditions caused visible deformation along the laser path and disrupted the integrity of the film surface.

Conversely, under Modes 4 (50%, 100 mm/s, 40 kHz), 5 (50%, 75 mm/s, 25 kHz), and 6 (50%, 200 mm/s, 40 kHz), only isolated crater-like features (~1.5 µm in diameter) were observed, and the overall film structure remained intact.

The results obtained emphasize the importance of choosing the right laser exposure parameters to achieve a balance between effective surface modification and structural preservation of the polyimide substrate. Future work will focus on introducing a silicon–carbon intermediate layer to enhance crystallization and reduce substrate degradation during laser processing.

This work was supported by grant FZWN-2023-0004.

Nowadays, additive manufacturing (AM) via the Fused Filament Fabrication (FFF) 3D printing process offers promising opportunities for the customized manufacturing of ankle–foot orthoses based on polypropylene (PP). However, optimizing printing parameters remains a major challenge due to the specific properties of this polyolefin, particularly its low interlayer adhesion and volumetric shrinkage. The primary innovation of the present work lies in the optimization of printing conditions for the production of patient-specific orthoses using PP, a material still underutilized in the AM of biomedical devices. Firstly, a thorough thermo-mechanical characterization was conducted, allowing the implementation of a (thermo-)elastic material model for the used PP filament in the simulation software database (Digimat-AM®). Thereafter, a Taguchi design of experiments was established to study the influence of several printing parameters (extrusion temperature, layer thickness, infill density, infill pattern and part orientation) on the mechanical properties of 3D printed specimens. Three-point bending tests were conducted to evaluate the strength and stiffness of the samples, while additional tensile tests were performed on the 3D printed orthoses according to ISO 22675 standard to validate the optimal configurations. Finally, the applicability of the finite element method (FEM) to simulate the FFF process-induced deflections, part distortion (warpage) and residual stresses in 3D printed orthoses was investigated using Digimat-AM® numerical simulation tool. The comparison between experimental results and numerical simulations enabled the proposal of an optimized set of parameters, ensuring improved quality and robustness of the printed orthoses. The findings of this study contribute to a better understanding of ankle–foot orthosis 3D printing with polypropylene, paving the way for more reliable and customized production targeted towards rehabilitation purposes.

This study focused on the modification of polylactide (PLA) nonwoven fabric using two distinct approaches: in situ polymerization and the spraying of a polymer solution in ethanol. The objective was to evaluate how the modification method and the amount of polymer influence the hydrophilic and thermal properties of the material. The modification process involved the use of N,N-dimethylaminoethyl methacrylate (DMAEMA), which was either polymerized directly on the PLA surface or applied in its pre-polymerized form as poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA).
The effectiveness of the modifications was assessed using Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), as well as water absorption and moisture sorption measurements. The results clearly demonstrated that the modification technique significantly impacts the material's functional performance. In situ polymerization enabled a more durable anchoring of the polymer to the fiber surface, resulting in enhanced hydrophilicity and improved thermal stability compared to the spraying method. The findings suggest that both modification methods hold potential for tailoring PLA nonwovens for advanced applications. However, in situ polymerization proved more effective in achieving stronger and more uniform functionalization. These insights are particularly valuable for the development of functional materials in fields such as biomedical engineering, hygiene products, and filtration systems, where moisture management and thermal resistance are critical.

Laser-based colloid synthesis has emerged as a powerful and versatile technique in nanoscience, offering a clean, surfactant-free route to the production of functional nanomaterials. This approach is gaining increasing attention due to its wide application in energy, catalysis, photonics, and biomedicine. In particular, composite nanoparticles—comprising combinations of metals and metal oxides—generate great interest. Their unique physicochemical properties arise from nanoscale interactions and can be fine-tuned by controlling parameters such as composition, morphology, and structural architecture.

Metallic nanoparticles such as copper (Cu) are well known for their plasmonic behavior, bactericidal properties, catalytic efficiency, and thermal conductivity, making them valuable in various applications from electronics and optoelectronics to medicine. Copper oxides (Cu₂O, CuO), as semiconducting materials, play a key role in sustainable technologies, including hydrogen production by water splitting, photocatalysis for environmental remediation, and sensor development. These oxides also exhibit antibacterial and catalytic activities, which further enhance their multifunctionality.

Our research focused on the laser fabrication of Cu\Cu-oxide composite nanoparticles under varying conditions of laser fluence, irradiation time, precursor material, and solvent environment. We investigated the mechanisms underlying their formation, the interplay between processing parameters and particle structure/composition, and how these factors affected key properties. The results of our study, along with an evaluation of the antibacterial and electrocatalytic activities of the obtained composites, will be presented.

This research was partially supported by the Polish National Science Centre under grants No. 2018/31/B/ST8/03043 and No. 2022/06/X/ST3/01743, and partially by the Kosciuszko Foundation Exchange Program to the United States.

This article presents a textile laminate system with heating and relative humidity measurement functions. The laminate was designed specifically for specialized protective clothing for workers. The goal was to design a method for manufacturing a layered textile laminate that incorporates a heating and measurement system without compromising the user’s comfort. The laminate should be characterized by appropriate thermal resistance values, increased durability of printed electrically conductive traces, and directional water vapor transmission from the underwear under varying conditions of relative humidity and moisture content within the garment structure. This goal was achieved by sequentially modifying the textile laminate layers to appropriately combine functions such as a moisture barrier, water vapor transmission, heating, and humidity measurement. Inkjet printing technology was used for that purpose. The system was powered by a 3.7-volt lithium-ion battery and utilized Wi-Fi communication. This article presents a measurement data acquisition system and a web-based application for monitoring and managing the thermal properties of the laminate. Environmental tests were conducted at various relative humidity levels to determine the system's effectiveness.

The main conclusions are as follows:

1. The heating module's efficiency is higher than 8°C/W as a function of heating power. A temperature increase of 8°C was achieved by supplying 0.5 to 0.16 W of power to a heating pad with a width of 2 to 6 mm. The maximum efficiency achieved for the heating module in the research is 47°C/1W of power.
2. The expanded uncertainty (U RH) of the humidity of the printed sensor on the knitting laminate substrate is less than 9%. The following was achieved: URH = 8.83%.
3. The relationship between the static temperature of the heating module and the supplied power is linear.

These interactive laminates fit into the concept of smart clothing, especially protective clothing for workers.

Corrosion protection of metallic structures is essential in aggressive environments, especially for reinforced concrete exposed to chlorides, which significantly accelerates deterioration of embedded steel. This study investigates electroless Nickel coatings on carbon steel rebars as a protective strategy to enhance corrosion resistance in such conditions. Plain carbon steel rebars were coated with nickel and its alloys, using an electroless deposition process. X-ray diffraction, scanning electron microscopy, optical profilometry, and atomic force microscopy were performed to analyze the presence of the Ni-P and Ni-P-W coatings’ phases, their morphologies, and topographies. X-ray diffraction confirmed the presence of Ni and Ni₃P phases for Ni-P and Ni-P-W coatings, whereas Scanning electron microscopy revealed uniform coatings and small island-like features. Energy dispersive spectroscopy analysis confirmed the elemental compositions of Ni-P and Ni-P-W in the respective coatings. Optical profilometry determined a surface roughness of ~0.7µm for Ni-P coating and ~3.1 µm for Ni-P-W coatings deposited at an optimized temperature of 85°C. To analyze the efficacy of the coatings, potentiodynamic polarizations were performed using a 3-electrode system, demonstrating improved corrosion resistance and indicating their potential application in marine infrastructure, coastal buildings, and chloride-contaminated construction sites. The results suggest that electroless Ni-based coatings can significantly improve the service life of steel-reinforced concrete structures in harsh environments.

Triply Periodic Minimal Surface (TPMS) lattices produced by Laser Powder Bed Fusion (L-PBF) using AlSi10Mg were examined to assess their mechanical performance and structural reliability. This study focused on Face-Centered Rhombic Dodecahedron (FRD) structures, including both uniform and functionally graded variants (FRD-30, FRD-40, FRD-45), and compared them with Gyroid and Fischer–Koch–S topologies, all designed with a relative density of 45%. Quasi-static compression tests carried out in accordance with ISO 13314 standards revealed that FRD-40 provided the highest elastic modulus, reflecting superior stiffness and load-bearing capacity. In contrast, the Fischer–Koch–S design achieved the highest total and specific energy absorption, coupled with a uniform defect distribution and minimal pore volume, making it well-suited for energy-dissipative applications. FRD-30 further demonstrated stable deformation and smoother stress–strain behaviors relative to its uniform counterparts. Defect morphology and internal porosity were characterized through high-resolution X-ray computed tomography (XCT), while fracture surface analysis by Scanning Electron Microscopy (SEM) identified delamination, unfused particles, and localized porosities that contributed to crack initiation and propagation. Finite Element simulations successfully captured the experimentally observed deformation and stress localization, validating the predictive power of the numerical models, while the Ashby–Gibson framework established density–property correlations and explained deviations caused by geometry and process-induced defects. Collectively, these results highlight how functional grading and topology optimization can improve the structural efficiency of AlSi10Mg TPMS lattices, offering valuable design strategies for demanding aerospace, automotive, and biomedical applications.

This study investigates the use of industrial mill scale waste as a sustainable source for developing an effective anti-corrosion pigment. Mill scale, a mixture of iron oxides (FeO, Fe₂​O₃​, and Fe₃​O₄​), forms as a crust on steel parts when heated above 575°C. Its formation is an unavoidable byproduct of steelmaking, hot or semi-hot forging, and hot rolling processes. To create the anti-corrosion pigment, we combined mill scale with a specific ore. We then incorporated this synthesized pigment into various protective coating formulations, systematically varying the proportions of mill scale at 100%, 42.85% and 28.57%. Prior to application on steel substrates, the substrates were polished to ensure optimal adhesion of the paint. The prepared coating formulations were characterized for their dry extract, flow time, and density. Electrochemical evaluation of the coated samples was performed using an AUTOLAB potentiostat-galvanostat controlled by ANOVA software. A standard three-electrode setup was employed for all experiments, consisting of a saturated calomel reference electrode, a platinum counter electrode, and the coated sample as the working electrode. The electrochemical analysis was conducted under specific operating conditions: a scan range of Ei​=0±250 mV/E.C.S, a scan speed of 1 mV/sec, and a 3.5% NaCl electrolyte. The results of the electrochemical analysis revealed significant anti-corrosion performance from the coatings. Notably, formulations containing the pigment with 28.57% mill scale demonstrated enhanced corrosion resistance. This research highlights a promising and sustainable approach to anti-corrosion solutions by effectively repurposing industrial byproducts.