In the present work, a series of eighteen new donor-acceptor (D-pi-A) organic molecules were designed using density functional theory (DFT) based on a benzothieno[3,2-b]benzothiophene (BT) core. The design successfully achieved significantly improved optoelectronic properties over the reference molecule. Key results include a reduced energy gap as low as 1.73 eV (3A), a lowered LUMO energy down to -3.37 eV (3A) for better alignment with the PC6,BM acceptor (LUMO = -3.50 eV), and a red-shifted absorption maximum up to 442.14 nm (2F). This yielded a higher theoretical open-circuit voltage, with the best-performing molecules (1D, 1E, 1F) achieving a VOC of 1.76 eV. The highest estimated power conversion efficiency reached 37.35% for compound 1D. These results are explained by a comprehensive analysis of the molecular properties. The BT it-bridge provided excellent planarity and intramolecular charge transport (ICT) characteristics. The strategic incorporation of electron-withdrawing groups (NO2, COOH, CN) at one terminal effectively lowered the LUMO energy, while donor groups (amine, methyl, ethyl) at the other end tuned the HOMO, optimizing the energy level alignment with PC6,BM. Computational analyses, including frontier molecular orbital (FMO) studies, global reactivity descriptors, electrostatic potential (ESP) mapping and transition density matrix (TDM), confirmed enhanced intramolecular charge transfer and chemical reactivity. Further investigation through parameters such as light harvesting efficiency (LHE up to 0.96 for 3A), reorganization energy, and transition density matrix (TDM) supported superior charge transport and excitation dynamics. Overall, all newly designed chromophores demonstrated favorable optoelectronic behavior, with the ethyl-substituted scheme (3A-3F) showing significant properties. Our results offer a strong computational methodology for creating D-pi-A materials with great performance for next-generation organic solar cells (OSCs).
Mesoporous nanoparticles that are magnetized have also been discussed as viable systems in combined chemohyperthermia delivery; nevertheless, a challenge of attaining high heating rates and efficient delivery of drugs to the targets has been a major challenge. This paper has produced folate-functionalized chitosan-coated magnetic mesoporous nanoparticles (CF-Doc-MMNPs) used in synergistic treatment of triple-negative breast cancer. The central composite design was used to optimize the formulation to obtain improved magnetization, measured particle size and efficient drug release. Optimized nanoparticles were found to have a homogeneous core-shell morphology with a mean hydrodynamic diameter of approximately 256 nm and a large surface area (approximately 150 m 2/g). A high specific absorption rate (SAR) of therapeutic hyperthermic temperatures was reached through magnetic characterization which established superparamagnetic behavior and the system had high specific absorption rate (SAR) of 113.62 W/g. The nanoparticles demonstrated that they had pH-responsive and sustained drug release, and the release was enhanced in the presence of acidic tumor conditions. In vitro cytotoxicity analyses of MDA-MB-231 cells showed that CF-Doc-MMNPs (LC 50 = 4.190 ug/mL) had a high anticancer activity due to the synergistic of magnetic hyperthermia and targeted drugs delivery in vitro. The current research is a multifunctional nanoplatform with high heating efficiency, controlled release, and folatemediated targeting which could be useful in chemo-hyperthermia of aggressive breast cancer.
Dynamic infrared thermal-radiation modulation technology has garnered significant attention for its ability to overcome the limitations of static techniques and broaden its range of applications. This study presents a dynamically tunable infrared thermal emitter based on near-zero permittivity films and In3SbTe2 (IST) phasechange materials. The device employs a multilayer thin-film structure, achieving dynamic switching of infrared functionality via laser-controlled phase transitions between the crystalline and amorphous states of IST. Simulation results indicate that, when IST is in the crystalline state, the device exhibits an average emissivity higher than 0.8 in the 9.9-14.9 mu m band for p-polarized light within the incident-angle range of 69 degrees-83 degrees, making it suitable for applications in infrared stealth and heat dissipation. When IST is in the amorphous state, the device exhibits an average transmittance higher than 0.7 in the 3.0-5.0 mu m band and higher than 0.6 in the 8.0-12.0 mu m band for p-polarized light over incident angles of 0 degrees-80 degrees. This emitter operates without static power consumption and allows for reversible switching among infrared stealth, heat dissipation, and transmission functions. This multifunctional emitter shows promising application potential in aerospace thermal management, precision thermal control, and energy recovery.
In recent years, the development of nanomaterials with efficient photothermal response has attracted widespread attention as a novel approach to non-invasive cancer treatment. In this study, the MoS2-Silk fibroin hybrid was synthesized with targeted MoS2 phase engineering from 2H to 1T to enhance the photothermal efficiency. Various characterization techniques, including XRD, FTIR, Raman, XPS, SEM, and TEM, confirmed the successful hybridization process. Photothermal evaluations showed that the optimal composition, with a 0.10:1 SF-to-1T-MoS2 ratio (MS0.10), increased the solution temperature by about 53 degrees C after 7 min of NIR laser irradiation. The effects of nanohybrid concentration, laser power, and thermal stability were also investigated, and the results indicated that the nanohybrid exhibited stable, efficient performance under different conditions. Biocompatibility studies on L-929 fibroblast cells showed that the MoS2-SF nanohybrid (MS0.10) at a relatively high concentration of 5 mg/mL maintained a viability of about 75% after 3 days of culture, indicating good biocompatibility. In addition, an MTT assay on MCF-7 breast cancer cells showed that after 7 min of NIR irradiation with MS0.10 (200 mu g/mL), tumor cell viability decreased to approximately 31%, confirming the high efficiency of this nanohybrid in inducing cell death. Overall, the results of this study indicate that the MoS2-SF nanohybrid, in its 1T phase and with enhanced photothermal performance, can be proposed as a promising nanoplatform for photothermal cancer therapy.
The AlCoCrFeNi2.1 eutectic high entropy alloy (EHEA) is a model system for achieving high strength-ductility balance via its duplex lamellar FCC/B2 microstructure. However, its defect sensitivity and underlying toughening mechanisms remain underexplored, particularly following thermomechanical processing. In this study, fracture toughness and crack propagation behavior are evaluated for both as-cast (AC) and hot-rolled (HR) EHEA variants. The HR microstructure exhibits enhanced tensile properties due to refined lamellae which delay damage initiation. Fracture toughness is reduced in the HR variant however, due to diminished crack blunting and suppression of extrinsic toughening mechanisms such as grain bridging. Post-fracture analysis reveals mixedmode propagation in the AC condition to predominantly BCC cleavage in the HR variant, coinciding with reduced FCC continuity at the crack tip. These results demonstrate the competition between damage initiation resistance versus crack propagation resistance to provide toughness and gives insights into optimization strategies for duplex EHEAs.
A machine learning force field (ML-FF) based on a higher-order equivariant message-passing framework is developed to investigate the structural and elastic properties of (3-cyclotetramethylene tetranitramine ((3-HMX). An active learning strategy is employed to construct a high-quality training dataset, enabling the ML-FF to achieve near-density functional theory (DFT) accuracy in predicting energies, atomic forces, and stresses. Compared with conventional force fields, the developed ML-FF shows improved agreement with both DFT calculations and experimental data in describing molecular structures, intermolecular interactions, and surface energies. The validated model is further applied to examine the elastic response of (3-HMX under hydrostatic pressure and varying vacancy defect concentrations. The results reveal that both bulk and shear moduli increase with increasing pressure but decrease with increasing defect content. Notably, under high-pressure conditions, vacancy defects have a more pronounced effect on shear modulus than on bulk modulus, indicating enhanced sensitivity of shear deformation to structural imperfections. This study demonstrates the capability of machine learning force fields in accurately capturing the mechanical behavior of energetic molecular crystals and provides valuable insights for the design and safety assessment of HMX-based energetic materials.
Metasurfaces have shown rich potentials in controlling acoustic and electromagnetic (EM) waves. However, the existing full-space wavefront manipulation solutions are limited to a single physical field. Here, the EM-acoustic dual-physical transmission-reflection-integrated coding metasurface (DTRIM) which is composed of a tri-layer structure is proposed. Specifically, the DTRIM can independently and continuously manipulate transmitted/reflected EM wavefronts via switching polarization states of incident EM waves and reflected acoustic wavefronts, achieving a tri-channel wavefront manipulation on a single platform. Simulations demonstrate that the DTRIM can arbitrarily merge multiple functions including multi-beam generation, focusing and holograms in full-space. This work enables dual-physical full-space wavefront control and significantly enriches the functionalities of metasurfaces, paving the way for integrated multifunctional EM-acoustic devices.
Recent advances in halide perovskites have transformed photovoltaics and optoelectronics, but their large-scale adoption remains limited by instability, toxicity, and environmental concerns. Pseudohalide perovskites, in which conventional halides are replaced by anions such as SCN-, CN-, N3-, BF4-, and ClO4-, have emerged as promis ing alternatives with improved stability and tunable electronic properties. In this work, four machine learning pipelines are developed to predict the bandgaps of pseudohalide perovskites with ABX3 composition. The dataset combines entries from the Materials Project, OQMD, and Hybrid Organic-Inorganic Perovskites (HOIP) databases and is augmented with synthetic pseudohalide structures. Feature engineering includes geometric descriptors such as tolerance factor, octahedral factor, and ionic radii, together with electronegativity differences, polarizabilities, HOMO-LUMO gaps, dipole moments, and HOIP-specific parameters. Among the models studied, XGBoost delivers the best performance (R2 = 0.948, MAE = 0.170 eV), with B-X electronegativity difference, B-site electronegativ ity, and tolerance factor emerging as the most important features. Virtual screening identifies several promising candidates in the 1.0-3.0 eV range, including EABi(ClO4)3 (2.55 eV), KSn(ClO4)3 (2.44 eV), and FAPb(BF4)3 (2.70 eV). These results demonstrate the ability of machine learning to navigate sparse pseudohalide datasets and accelerate the discovery of sustainable, high-performance optoelectronic materials.
Malignant tumors remain a major global health burden due to high mortality and limited therapeutic efficacy. Nanomaterials offer promising strategies for cancer treatment owing to their tunable physicochemical properties. In this study, a multifunctional MIL-101@ICG@FA nanocomposite was constructed to integrate photothermal, photodynamic, and chemodynamic therapies. The Fe-based MOF exhibited high porosity and loading capacity, enabling effective incorporation of indocyanine green. The nanoplatform displayed strong photothermal conversion, enhanced reactive oxygen species generation, and Fenton-like catalytic activity under near-infrared irradiation. In-vitro assays demonstrated potent cytotoxicity against tumor cells, while in-vivo experiments confirmed efficient tumor growth inhibition with no obvious toxicity observed in the short-term evaluation. These findings highlight the synergistic therapeutic advantages of MIL-101@ICG@FA and support its potential as a promising candidate for multimodal cancer therapy.
Nanoparticle properties depend strongly on ligand and surface states. Control of surface conditions is important for stable synthesis and consistent performance. This study presents a solvent induced surface swelling approach of PVC films using DMF for the formation of MAPbBr3 nanoparticles. Temperature was used to control solvent dynamics during swelling under room-temperature and 0 degrees C conditions. Swelling at 0 degrees C reduced non-uniform solvent evaporation and penetration and resulted in more uniform swelling of PVC. The swollen region provided a confined space for nanoparticle formation. MAPbBr3 nanoparticles showed improved spatial distribution on the PVC surface under this condition. Structural and optical properties were characterized. The results indicate that nanoparticle formation is governed by coupled diffusion and concentration-driven processes rather than simple deswelling. Optical measurements were performed under cryogenic conditions.
Polydimethylsiloxane (PDMS)-based triboelectric nanogenerators (TENGs) embedded with 14 vol.% 0.80Na0.5Bi0.5TiO3-0.20BaTiO3 (NBT-20BT) particles of different sizes were prepared, and their morphol ogy, temperature and frequency dielectric properties, as well as triboelectric output performance, were studied. A series of powders prepared with progressively longer milling durations showed that the particles became finer and their size distribution became narrower, as indicated by the Weibull distribution statistical analysis. The NBT-20BT/PDMS composite films exhibit a low-temperature dynamic glass transition anomaly dependent on NBT-20BT particle size. Due to strong interaction between PDMS and NBT-20BT, the glass transition temperature shifts to higher values than in pure PDMS. The triboelectric output performance of the NBT-20BT/PDMS-based TENGs, tested against an Al foil in a vertical contact-separation mode under a pressing force of 10 N, exhibited a non-monotonic behavior. For the most efficient sample, the triboelectric parameters reached 6.06 & micro; A, 9.78 nC/cm2, and 6.23 & micro;W/cm2 for the short-circuit current, charge density, and output power density, respec tively. The observed maximum in the triboelectric properties across the series is explained by the agglomeration of the corresponding powder within the PDMS, as revealed by scanning electron microscopy. An important correlation for the NBT-20BT/PDMS composite films was observed: the TENG output performance depends on the glass transition temperature in a near-linear manner.
Due to their unique structural and chemical properties, ceramic scaffolds are vital for various high-performance functional applications, with bone tissue engineering being a highly relevant research field. In this context, the present study aimed to fabricate and characterize Al2O -based scaffolds containing 5 vol% of nanometric zirconia inclusions, formulated with PEG-Laponite (R) using the direct ink writing (DIW) technique. The influence of ceramic solid loading (40, 50, and 60 vol%) and different extrusion nozzle inner diameters on the rheological behavior, extrudability, printing fidelity, and structural characteristics of the resulting scaffolds was investigated. The formulations exhibited favorable rheological performance, with stable viscosity and good shear recovery, ensuring extrudability and shape retention during printing. The 0.51 +/- 0.03 mm nozzle was most effective for the 60 vol% formulation, achieving high-resolution filaments and pores essential for mimicking bone microarchitecture. The ceramic loading significantly affected the microstructure, shrinkage, and mechanical strength, with 60 vol% leading to higher densification and compressive strength. The hierarchical porous architecture, consisting of well-defined macropores and interconnected micropores, was confirmed by micro-computed tomography. Furthermore, biological assays with Saos-2 cells demonstrated high cell viability and strong adhesion on the 60 vol% scaffolds, confirming their excellent biocompatibility and potential suitability for bone tissue engineering applications.
Biodegradable magnesium alloys have emerged as promising candidates for orthopedic fixation due to their favorable mechanical compatibility and inherent ability to degrade in physiological environments. However, corrosion-induced degradation leads to time-dependent changes in implant geometry and stiffness, significantly influencing load transfer and biomechanical performance. In this study, a time-dependent multiphysics computational framework is developed to investigate the coupled effects of degradation and mechanical behavior in a biodegradable Mg-2Zn implant embedded in cortical bone. The model integrates corrosion-driven geometry reduction with stiffness degradation and finite element analysis to simulate the evolving bone-implant interaction under dominant axial compressive loading conditions over a 12-month healing period. The results demonstrate that progressive degradation reduces the implant elastic modulus from 43 GPa to 20.9 GPa, leading to improved stiffness compatibility and enhanced load sharing with surrounding bone. Consequently, the average cortical bone stress increases from 12.4 MPa to 16.4 MPa, corresponding to approximately 32% stress recovery, while the stress shielding index decreases by nearly 60%. Despite material loss, implant stresses remain well below the yield strength, indicating adequate structural integrity throughout the healing process. Parametric analyses further reveal that implant diameter and degradation rate critically govern the balance between mechanical stability and stress shielding mitigation. These findings highlight the importance of degradation-controlled design and demonstrate the potential of multiphysics modeling as a predictive tool for optimizing next-generation biodegradable magnesium-based orthopedic implants.
Water pollution by synthetic dyes like crystal violet (CV) poses severe ecological threats. This study introduces biopolymer-modified Zn-Fe layered double hydroxides (LDHs) as high-performance, sustainable adsorbents for the removal of CV. Three composites were synthesized via coprecipitation using chitosan, carrageenan, or cellulose and were comprehensively characterized. The properties of prepared materials were studied by SEM, EDX-Mapping, FT-IR, XRD, BET, and Rietveld refinement. Structural analysis revealed distinct morphologies: Zn-Fe LDH/chitosan showed aggregated nanosheets with the highest surface area (63.0 m & sup2;/g), while Zn-Fe LDH/carrageenan exhibited a rough surface with hydrogel nanoparticles and the largest pores (34.0 nm). Rietveld refinement confirmed that all composites retained the hydrotalcite-type LDH phase as the dominant crystalline phase with no detectable secondary oxide phases (ZnO, Fe2O3, Fe3O4, or Zn (OH)(2)), thus verifying phase purity and confirming that Zn and Fe species are exclusively incorporated within the LDH framework. Adsorption studies identified Zn-Fe LDH/chitosan as the superior adsorbent, achieving a Langmuir capacity of 477.0 +/- 9.0 mg/g and 84.51% removal at optimal conditions. Zn-Fe LDH/carrageenan also performed excellently at a lower dosage (458 +/- 11 mg/g, 84.03%) at 298 K. Kinetics followed pseudo-second-order (R & sup2; > 0.99). Complete Langmuir isotherms were measured at four temperatures (298-328 K) for all adsorbents A comparative assessment highlighted chitosan's superiority due to its balance of high capacity, rapid kinetics, and cost-effectiveness (0.53 USD/g). The removal efficiency for CV still reached 70.50% after six cycles. Post-adsorption FTIR analysis revealed a broadening and red-shift of the O-H stretching band (similar to 3400 cm(-)& sup1;) for all composites after CV uptake, providing spectroscopic evidence for hydrogen bonding contributions to the adsorption mechanism alongside electrostatic attraction, pi-pi stacking, metal-site Lewis acid-base interactions, and ion exchange. The environmental sustainability of the composites was validated using AGREE (overall score 0.75) and MOGAPI metrics, confirming alignment with green chemistry principles. The thermodynamic analysis showed spontaneous CV adsorption using three tested materials. This work advances the design of biopolymer-LDH hybrids, offering an efficient, scalable, and eco-friendly solution for dye-contaminated water remediation.
The poor stability of polyvinyl alcohol (PVA) electrospun mats in an aqueous medium has limited their use in biomedicine. In this study, electrospun double-layer PVA mats containing a very low amount of silver oxide nanoparticles (Ag2ONPs) and ciprofloxacin hydrochloride (CIP), both independently and in combination, are reported. The mats were thermally crosslinked and thoroughly characterized to confirm crosslinking and the presence of Ag2ONPs and CIP. The release behavior of the Ag2ONPs and CIP from the mats was studied using atomic absorption spectroscopy and UV-visible spectrophotometry, respectively. The mats' antimicrobial activity was evaluated using a time-kill assay against reference and multidrug-resistant bacteria. Cytotoxicity was determined in human dermal fibroblasts (HDF) using calcein/ethidium homodimer and MTT assays. Results showed that crosslinking occurred, increasing the PVA melting temperature and stability in water. The average fiber diameter of the mat without antimicrobial agents was 412.50 nm, and the addition of CIP increased the diameter. XRD confirmed the presence of Ag2ONPs in the mats, and infrared spectra indicated that the antimicrobial agents interacted with the PVA through van der Waals forces. The kinetics of CIP release from the electrospun mats showed burst release during the first 30 min, followed by a sustained release. The maximum Ag concentration was reached after two hours of immersion. Furthermore, the PVA mat containing both antimicrobial agents exhibited a synergistic effect, requiring lower concentrations and shorter exposure times to inhibit the growth of multidrug-resistant bacteria compared to mats loaded with Ag2ONPs or CIP alone. Finally, the double-layer mats did not alter the morphology or mitochondrial metabolism of HDF.
Grounding Systems (GS) installed in high-resistivity soils often require Ground Enhancement Materials (GEM) to reduce soil resistance and ensure stable electrical performance over time. However, many conductive materials exhibit high initial conductivity but suffer degradation under environmental exposure, which may compromise the long-term reliability of grounding installations. In this study, the electrical and electrochemical performance of GEM mixtures formulated from sodium bentonite, marine carbon, ferric oxide, and amorphous graphite was systematically evaluated using a Simplex-Centroid Mixture Design (SCMD). Fifteen formulations were prepared and characterized in terms of electrical conductivity (EC), pH, and oxidation-reduction potential (ORP). The mixtures were subsequently subjected to an accelerated aging protocol simulating intensive wetting-drying cycles representative of severe climatic conditions. The results indicate that EC is strongly governed by the presence of amorphous graphite and ferric oxide and their synergistic interactions, reaching values above 14,000 & micro;S/cm in optimized formulations. High-performance mixtures maintained elevated conductivity during the aging process, demonstrating strong resistance to degradation under repeated wetting-drying cycles. Across all formulations, mean pH values ranged from 5.51 to 8.63; however, instantaneous minimum values as low as 4.50 were recorded for M2 and M4, and maximum values up to 9.50 were observed for M1, and ORP values were predominantly negative, indicating electrochemically favorable conditions for copper stability. Interpretation using Pourbaix diagrams suggests that the evaluated systems fall within the immunity or passivation domains of the Cu-HBO system, indicating a low corrosion risk for copper electrodes. Overall, the proposed methodology provides a practical framework for the design of stable and electrochemically compatible GEM formulations for GS exposed to variable environmental conditions.
The application of polymer-based drilling fluids in the drilling process involves gel formation; therefore, before gelation, such fluid samples must possess injectability, pumpability, and stability in different ranges of shear stress and temperature. At present, there is no comparison study of commercial polymer drilling fluids under similar rheological conditions. The rheological performance of five water-soluble polymers, namely, AN 105 (1.5 wt%), AN 125 VHM (0.75 wt%), AN 125 VLM (2 wt%), polyacrylamide (3 wt%), and hydroxyethyl cellulose (2 wt%), was determined with a rotational viscometer over a wide temperature range of 25-90 degrees C. For comparative analysis of the rheological behavior of the considered drilling fluids, two dimensionless screening parameters, i.e., shear thinning index (STI) and thermal stability index (TSI), were chosen. It was established that all selected polymers demonstrated non-Newtonian behavior, being shear thinning. However, a significant difference in the ability to maintain low-shear viscosity in high-temperature mode was detected. The best results in terms of rheological performance were obtained for AN 125 VHM.
Shape memory polymers (SMPs) can be programmed to a temporary shape and recover when heated, enabling 4D printing. In this study, 3D/4D printing with PETG-PLA blends was investigated to overcome PLA brittleness while preserving printability and enabling fast, heat-triggered actuation. Blends across PETG-PLA, including 90/ 10, 75/25, 60/40, 40/60, 25/75, and 10/90 were melt-mixed, pellet-fed printed, and characterized by tensile testing, dynamic mechanical thermal analysis (DMTA), printability, morphology, and shape recovery. Strength was observed to rise with PLA content, reaching 43.69 MPa for PETG-PLA 10/90, while energy absorption to the UTS point was maximized for 25/75 at-327 mJ. DMTA identified two composition-dependent softening windows, a PLA-related transition at-55-65 degrees C and a PETG-related transition at-65-75 degrees C, with all blends converging to a similar rubbery plateau. SEM revealed immiscible morphologies that tracked performance, including a PLA-matrix sea-island texture for 25/75 and 10/90 and a bonded co-continuous network near 40/60. All blends exhibited high shape fixity, but recovery behavior varied with composition: 25/75 displayed the fastest early recovery, while 90/10 achieved the highest final recovery. Overall, the results demonstrate that pellet-fed PETG/PLA blends offer composition-tunable trade-offs among stiffness, strength, toughness, and thermal actuation, with 25/75 favoring toughness and fast recovery, 10/90 providing the best strength-toughness balance, and 90/10 giving the highest terminal recovery.
In modern materials research, reduction of fossil fuel consumption has triggered massive research on bio-based alternatives, especially for polymer composites. While resins in research are frequently replaced by bio-based alternatives, bio-based flame retardants are rarely investigated. This work covers the introduction of nitrogenbased phytates and magnesium phytate into an unsaturated polyester (UP) resin and their influence on mechanical characteristics and flame retardancies. The UP resin is based on 1,3-butanediol and fumaric acid with isobornyl acrylate as the reactive dilutant. The ammonium, piperazinium, melaminium, or magnesium phytates are characterised by FT-IR spectroscopy and 31P NMR spectroscopy for phosphorus quantification. Resin plates were cured without phytates, including 10 parts per hundred parts of resin (phr) of phytate, or 20, 40, and 60 phr for magnesium phytate. The resin plates were characterized by Dynamic Mechanical Analysis (DMA) and Cone Calorimetry. The DMA results remain similar for all plates (glass transition around 125 degrees C). Upon combustion, nitrogen-based phytates exceed magnesium phytate in reductions of the Maximum Average Rate of Heat Emission (-44% for ammonium vs. up to -35% for magnesium), Total Heat Release (-37% for ammonium vs. up to -25% for magnesium), and Total Smoke Release (-22% for ammonium vs. up to -25% for magnesium). However, they suffer from carcinogenic or teratogenic characteristics, and/or show disadvantageous solubility in water. Additionally, magnesium phytate has 100% biobased carbon content. Still, industrial criteria as formulated in, e.g., DIN EN 45545-2 for railway applications are not met with the presented formulations requiring further optimization before application in composites.
This study investigated the effect of solution heat-treatment temperature on the work-hardening and aging behavior of Cu-Ni-Si-Co-Cr-Sn alloy for lead-frame and connector applications requiring both high strength and high electrical conductivity. The alloy was solution heat-treated at 830 and 930 degrees C, cold-rolled under uniform and non-uniform deformation conditions, and subsequently aged to evaluate its mechanical properties and microstructural evolution. The specimen solution heat-treated at 830 degrees C showed relatively limited hardness increases during both cold rolling and subsequent aging. This behavior was attributed to the low solubility at the lower solution heat-treatment temperature, which left a large amount of residual inclusions in the matrix and reduced the concentration of solute atoms, thereby reducing the work-hardening response during subsequent cold rolling. In addition, during aging, coarse particles were preferentially observed near pre-existing inclusions and grain boundaries, reducing the efficiency of fine precipitation strengthening. In contrast, the specimen solution heat-treated at 930 degrees C exhibited a greater hardness increase during cold rolling and a much stronger agehardening response. This was because the higher solution heat-treatment temperature promoted the dissolution of residual inclusions and increased the solute concentration in the matrix, thereby improving the workhardening capability. Furthermore, the increased dislocation density introduced by cold rolling may have accelerated solute transport along dislocation structures during aging, thereby promoting more effective fine precipitation. These results demonstrate that high-temperature solution heat treatment is effective in achieving a superior combination of strength and electrical conductivity in Cu-Ni-Si-Co-Cr-Sn alloy through subsequent rolling and aging treatments.
