Thin-walled NiTi alloy tubes are key raw materials for interventional stents and precision biomedical devices, whose performance depends strongly on microstructure and surface quality. This study systematically investigates the relationships among processing history, grain structure, surface condition, mechanical response, passive-film characteristics and electrochemical corrosion behavior in imported NiTi tubes (JK), domestic as-received tubes (GC-1) and process-optimized domestic tubes (GC-2). JK exhibits finer, more uniform grains (ASTM No. 11) and lower inner-surface roughness (R a = 0.115 mu m) than GC-1, leading to the highest plateau stress (473 MPa), densest passivation film and lowest corrosion rate (0.37 mu A/cm2). After multi-pass cold rolling and fine inner-surface polishing, GC-2 reaches ASTM No. 10 grain size and R a = 0.138 mu m, the highest elongation (15.1%) and a 71% lower corrosion rate than GC-1. These findings provide guidance for developing high-performance domestic NiTi tubes.
In this study, a beta-type Ti-3Al-6Fe-6V-2Zr (wt.%, hereafter referred to as Ti3662) alloy lattices with cubic (CUB), rhombic dodecahedron (RHO) and topology-optimised (TOP) unit cells were fabricated using the laser powder bed fusion (LPBF) technique. Compression tests were conducted at various strain rates, and the results were compared with those of Ti-6Al-4V lattices. The findings show that both compressive strength and energy absorption efficiency increase with increasing strain rate, although to different extents depending on the lattice geometry. The bending-dominated TOP lattice exhibits the highest strain-rate sensitivity (SRS) because of enhanced structural rotational inertia and a more uniform stress distribution within the struts. In contrast, the buckling-dominated CUB lattice shows the lowest SRS and which is primarily governed by the intrinsic properties of the parent materials. Compared with Ti-6Al-4V lattice, Ti3662 lattices demonstrate higher SRS owing to their higher activation energy of dislocation slip mechanisms under various deformation rates.
This study investigates apricot shells as a sustainable precursor for synthesis of nanoporous activated carbon (AC) for high-performance electric double-layer capacitors (EDLCs). By separating carbonization (300-600 degrees C) and KOH activation, we demonstrate that carbonization temperature crucially governs the structural, chemical, and electrochemical behavior. Comprehensive XRD, FTIR, EDS mapping, and N2 sorption analyses revealed controlled tuning of the pore architecture, yielding a narrow mesopore distribution (3.5-4.0 nm). The optimized AC43 matrix (carbonized at 400 degrees C) achieved a specific surface area of 1200 m2/g, micropore volume of 0.47 cm3/g, and 20.8 wt.% of oxygen functionalities. In symmetric EDLC cells, AC43 delivered a stable capacitance of 88 F/g in organic LiBF4/GBL electrolyte (up to 2.4 V) and a remarkable 190 F/g in aqueous 30 wt.% KOH, exhibiting high capacitance retention and minimal voltage drop under current loads up to 360 mA/g. Optimizing pre-carbonization is a powerful strategy for designing structurally tailored biomass carbons for efficient energy storage.
In this study, two alloys T4822-0.1B(4)C and T4822-0.2B(4)C were fabricated. We systematically investigated their solidification structural evolution, grain refinement mechanism, room/high-temperature mechanical performance and creep resistance. Both as-cast alloys are dominated by gamma and alpha(2) phases with near-lamellar microstructures. Strip-like borides precipitate in the 0.1 at.% B4C alloy, while finer short-rod and rod-shaped borides appear in the 0.2 at.% counterpart. T4822-0.2B(4)C achieves better comprehensive properties, with a high-temperature tensile strength of 484 MPa at 800 degrees C, greatly exceeding its room-temperature strength and showing more stable high-temperature performance than T4822-0.1B(4)C. T4822-0.1B(4)C lacks a notable accelerated creep stage, whereas T4822-0.2B(4)C owns superior creep resistance and exhibits obvious toughening fracture features.
Renewable energy requires photovoltaic (PV) technologies, which can overcome the drawbacks of previously researched silicon cells in efficiency, heaviness, and price. Perovskite nanomaterials are promising options, but questions about their stability and practical use remain unresolved. This research investigated La(1-x)Sr(x)MnO3 (LSMO) nanoperovskites as performance-enhancing coatings on PV cells. The samples of LSMO with different concentrations of Sr (x = 0.5, 0.7) have been synthesised by co-precipitation and identified using XRD, FTIR, UV-Vis, photoluminescence, BET surface analysis and antimicrobial tests. The composition-dependent reduction in the grain size, surface area and modulation of the band gaps (5.69-5.94 eV) were found to enhance photon absorption and charge transport. LSMO coatings incorporated greatly increased the output power and efficiency, with x = 0.7 composition improving the efficiency by almost 40% over that of the uncoated cells. Critical knowledge gap between the design of perovskite materials and actual PV operation, demonstrating that LSMO is a potentially successful source of solar technology.
The fostering of direct nucleation of polymer crystals on the CNT surface and tuning of hierarchical structure through changes in crystallization conditions has the potential to overcome the technological barrier of strong interfacial strength in polymers containing nanoparticles. For instance, in photovoltaic devices, the interfacial interaction of CNTs with the polymer determines the efficiency of photogenerated excitations and electron transport. The solution-based approach that enables direct epitaxial nucleation and growth of hierarchically organized inorganic-organic hybrid nanoscale architecture is envisaged to shift the paradigm from interfaces with no apparent chemical interaction between the constituents, as in the traditional approach of blending polymers and nanoparticles to epitaxial nucleation and growth of crystalline nanofibrils of polymers on nanoparticle surface through pi-pi interactions.
This work focuses on W-0.4MoNb1.3TaTiCrx (x = 0, 0.25, 0.5, 0.75 at.%) refractory high-entropy alloys produced by vacuum arc melting. Their microstructure, mechanical behaviour and corrosion performance were systematically examined. X-ray diffraction and SEM confirmed a body-centered cubic matrix, with Laves phase formation increasing at higher Cr levels. A slight reduction in the lattice parameter and peak shifts toward higher angles indicated the substitution of larger atoms by smaller Cr atoms. Solid-solution strengthening analysis highlighted Cr's role in enhancing strength. The alloy with x = 0.75 achieved the highest yield strength (similar to 1550 MPa) but exhibited reduced ductility (similar to 10% fracture strain) due to brittle intermetallic phases. Corrosion tests in 3.5 wt.% NaCl showed improved resistance with Cr addition, attributed to the protective Cr-rich oxide layers. Overall, Cr significantly influences phase stability, mechanical properties, and electrochemical behaviour, offering pathways for optimizing RHEAs for demanding structural applications.
Thermoplastic polyurethane (TPU) is attractive for flexible strain sensors, but single carbon-filler systems often suffer from unstable conductive-network evolution and unreliable cyclic signals. Here, graphene (GR), carbon nanotubes (CNTs), and GR/CNT hybrid fillers were incorporated into TPU by solution blending to regulate network stability and shoulder-peak behavior. Among the investigated formulations, GCTP exhibited a tensile strength of 20.64 MPa, an elongation at break of 974.54%, GF values of 1.86, 183.14, and 1975.6, an effective sensing range of similar to 280%, and a response time of similar to 330 ms. It also maintained recognizable resistance signals after 5,000 cycles at 60% strain. Notably, GCTP showed smooth and shoulder-free resistance output during cyclic tensile testing and joint-motion monitoring. This behavior is associated with the combined contribution of conductive-filler network density and the GR/CNT hybrid architecture, which stabilizes conductive-pathway evolution and tunneling-distance recovery during cyclic deformation.
