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CFRP laser texturing to increase the adhesive bonding: morphological analysis of treated surfaces
摘要： Surface roughness of the adherends represents an important factor for manufacturing a reliable bonded joint in structural applications. In case of bonding of parts in carbon fibre reinforced polymer (CFRP), an increase of roughness parameters can be obtained with various techniques. In this paper, the morphology obtained from a CO2 laser texturing on CFRP laminates were investigated. CFRP laminates were manufactured and subjected to laser texturing with various densities. In particular, the densities of treatment have been defined as a function of the grid dimensions of the texture. Subsequently, non-contact measurements were carried out to evaluate the evolution of the surface roughness parameters as a function of the density of the laser treatment. Results showed a strong correlation between surface roughness and density of treatment. In conclusion, these results were compared with experimental tests, which showed that the mechanical performance for ENF bonded joints was limited only by the flexural mechanical resistance of the CFRP adherends. As a result of this work, the developed laser texturing approach is potentially able to increase the mechanical resistance in the function of the real local load acting on the complex bonded joint, optimizing time and cost process.
关键词： surface modification,surface roughness/morphology,Composites,adhesion by mechanical interlocking
更新于2025-09-23 15:21:01
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EXPRESS: Potentialities of a Laser-Induced Breakdown Spectroscopy Technique in the Study of Polymer Composites
摘要： A laser-induced breakdown spectroscopy (LIBS) technique was used to evaluate the filler content in particulate epoxy–copper composites. A potential application for a direct and fast measurement of the filler in composites through the LIBS results is suggested using calibrated samples. The methodology used in this work makes possible the incorporation of LIBS as a quantitative technique for the study of particle metal filled epoxy composites, providing a method to obtain a direct estimation of the filler volume fraction.
关键词： LIBS,Laser-induced breakdown spectroscopy,epoxy composites,copper,plasma
更新于2025-09-23 15:21:01
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Determination of Thermal Diffusivity of Basalt Fiber Reinforced Epoxy Composite using Infrared Thermography
摘要： In recent years, there is a great demand for ecofriendly, light weight and cost effective composites. Basalt fiber is one such naturally available fiber which offers exceptional properties over glass fibers. In this study a Basalt fiber reinforced composites were fabricated by vacuum bagging technique. Thermal properties of these composites were determined using infrared thermography. In-depth and in-plane thermal diffusivity are determined by using pulse thermography and space resolve method respectively. The in-plane thermal diffusivity was determined in the transmission and reflection modes. In-depth thermal diffusivity is validated using a Light flash method.
关键词： Infrared thermography,Non-Destructive Testing,thermal diffusivity,Basalt fiber reinforced composites,space resolved method
更新于2025-09-23 15:21:01
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Development of metal matrix composites by laser-assisted additive manufacturing technologies: a review
摘要： Metal matrix composites (MMCs) generally possess superior properties than the monotonic matrix alloys, and thus, they have become excellent candidate materials in various applications. Also, the ability of property tailoring at an affordable cost is of particular importance to industries. Among the many manufacturing techniques for MMCs, laser-assisted additive manufacturing (AM) techniques have emerged and drawn increasing attention in the past decade. In the literature, a wealth of studies have been carried out on the synthesis of MMCs via laser-assisted AM techniques, as well as the property evaluation of the obtained MMCs. In this paper, we review and analyze the relevant literature and summarize the material preparation, optimization of process parameters, resultant improvements, and corresponding strengthening mechanisms for each major category of MMCs. Moreover, the limitations and challenges related to MMC synthesis using the laser-assisted AM techniques are discussed, and the future research directions are suggested to address those issues.
关键词： Laser-assisted additive manufacturing,Process parameters,Material preparation,Strengthening mechanisms,Metal matrix composites
更新于2025-09-23 15:21:01
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Computational study of nonlinear dielectric composites with field-induced antiferroelectric-ferroelectric phase transition
摘要： Electric field-induced antiferroelectric-ferroelectric phase transition and the associated nonlinear dielectric behavior in particulate composites are investigated for achieving a high dielectric capacity. A phenomenological thermodynamic model based on the Landau theory is first developed to discuss the generic phenomena of a temperature-electric field phase diagram, coexistence of antiferroelectric and ferroelectric phases, field-induced antiferroelectric-ferroelectric phase transition, and nonlinear dielectric behavior. The model is then used to carry out the phase field simulation of particulate nonlinear dielectric composites. It is found that the composites exhibit nonlinear dielectric behaviors, and the depolarization field in the composites helps reduce the dielectric hysteresis and enhance the reversibility of antiferroelectric-ferroelectric phase transitions, which are desired for energy storage applications. The simulations also reveal the underlying domain-level mechanisms for nucleation and growth processes of the phase transitions. It is shown that the macroscopic properties of the composites sensitively depend on the directional alignment of the antiferroelectric filler particles, and thus the filler morphology is an effective control variable in designing nonlinear dielectric composites.
关键词： phase field simulation,energy storage,nonlinear dielectric composites,Landau theory,antiferroelectric-ferroelectric phase transition
更新于2025-09-23 15:21:01
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Influence of Matrix Nature on the Structural Characteristics of In2O3–CeO2 and SnO2–CeO2 Composites Fabricated by the Impregnation Method
摘要： The structural characteristics, valence states, and distribution of cerium ions between the components in In2O3–CeO2 and SnO2–CeO2 nanocomposites fabricated using the impregnation method were studied. X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDX) were used to show that, during impregnation, cerium ions are not included into In2O3 crystals and are disposed only on their surface in the form of nano-sized crystallites or amorphous clusters. On the other side, under the contact of CeO2 clusters with a surface of SnO2 matrix crystals, cerium ions penetrate into the surface layer of these crystals. In contrast to an In2O3–CeO2 system, where the addition of CeO2 does not affect the conduction activation energy, where cerium oxide is added to SnO2, the observed increase in the resistance of a SnO2–CeO2 composite is accompanied by a sufficient increase in activation energy. These data and the XPS spectra confirm the modification of the surface layers of conductive SnO2 crystals as, a result of the penetration of cerium ions into these layers.
关键词： cluster,conductometric sensor,metal oxide nano-sized composites,semiconductor,impregnation method
更新于2025-09-23 15:21:01
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Highly Efficient Inorganic-Organic Heterojunction Solar Cells Based on Polymer and CdX (X=Se, Te) Quantum Dots: An Insight from a Theoretical Study
摘要： By using the density functional method, we explore the potentiality of recently synthesized CdX (X=Se, Te)QD/P3HT composites in solar energy conversion devices. Our study reveals that inorganic/organic hybrid CdXQD/P3HT nanocomposites with larger size of CdX QDs exhibit type-II band alignment, suggesting efficient charge separation upon photoexcitation. But for smaller size of QDs, the composites show type-I band alignment which are devoid of charge separation and thus are not suitable for solar cell applications. To remove this obstacle, we focus on chemical modification to polymer P3HT. The substitution of hydrogen at the beta position of each thiophene ring of polymer by electron withdrawing group (CN) results type-II band alignment and yield spatial charge separation even for smaller size of QDs. Finally, we calculated the powerconversion efficiency (PCE) of CdXQD and CN functionalized P3HT nanocomposites. The maximum calculated PCE value of 10.82% is achieved, which makes them immensely competitive with other reported heterojunction solar cells.
关键词： CdX (X=Se, Te)QD/P3HT composites,powerconversion efficiency,solar energy conversion,charge separation,type-II band alignment
更新于2025-09-23 15:21:01
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Discerning Localized Thermal Heating from Mechanical Strain Using an Embedded Distributed Optical Fiber Sensor Network
摘要： Prior research has demonstrated that distributed optical fiber sensors (DOFS) based on Rayleigh scattering can be embedded in carbon fiber/epoxy composite structures to rapidly detect temperature changes approaching 1000°C, such as would be experienced during a high energy laser strike. However, composite structures often experience mechanical strains that are also detected during DOFS interrogation. Hence, the combined temperature and strain response in the composite can interfere with rapid detection and measurement of a localized thermal impulse. In this research, initial testing has demonstrated the simultaneous response of the DOFS to both temperature and strain. An embedded DOFS network was designed and used to isolate and measure a localized thermal response of a carbon fiber/epoxy composite to a low energy laser strike under cyclic bending strain. The sensor interrogation scheme uses a simple signal processing technique to enhance the thermal response, while mitigating the strain response due to bending. While our ultimate goal is rapid detection of directed energy on the surface of the composite, the technique could be generalized to structural health monitoring of temperature sensitive components or smart structures.
关键词： smart structures,distributed optical fiber sensors,temperature sensors,structural health monitoring,high energy radiation,polymer matrix composites,strain sensors,strain compensation
更新于2025-09-23 15:21:01
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Femtosecond laser surface engineering of biopolymer ceramic scaffolds coated with ZnO by low temperature atomic layer deposition method
摘要： Surface femtosecond laser texturing of biopolymer and biopolymer/ceramic composites with subsequent ZnO film deposition on the samples by low temperature Atomic Layer Deposition (ALD) method was performed. In the current study, the deposition of ZnO layers was implemented at temperature 50 °C under pressure of 2 mbar. In order to investigate the effect of diverse ZnO thin films thickness, 100 or 500 repeating ALD cycles were applied. The samples were exposed to ultra-short laser pulses of 130 fs duration generated by a CPA (chirped pulse amplifier) Ti:Sapphire laser system. The artificial scaffolds were irradiated by varying the laser fluence (0.2 J/cm2, 0.41 J/cm2 and 2.07 J/cm2) and the number of applied laser pulses (N = 1, 2, 5 and 10). The morphology and chemical properties of the treated samples were evaluated by Scanning Electronic Microscopy, Energy-Dispersive X-ray Spectroscopy and X-ray photoelectron spectroscopy. By combining fs laser modification with low temperature ALD method, essentially improved bioactivity properties of hybrid organic–inorganic bone tissue scaffolds could be achieved, which is of great importance for future tissue engineering application of the samples.
关键词： Atomic layer deposition,Biopolymer/ceramic composites,Femtosecond laser modification,Tissue engineering
更新于2025-09-23 15:21:01
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CaBi <sub/>4</sub> Ti <sub/>4</sub> O <sub/>15</sub> -based lead-free sol–gel composites for high-temperature application
摘要： CaBi4Ti4O15 (CBiT)-based lead-free sol–gel composites were developed for high-temperature ultrasonic transducer application. In this study, two types of lead-free sol–gel solution, Ba0.7Sr0.3TiO3 (BST) and Bi4Ti3O12 (BiT), were used for consistency to fabricate >50-μm-thick CBiT/BST and CBiT/BiT ?lms on 3-mm-thick titanium substrates by a sol–gel spray technique. BST and BiT were chosen because of their high dielectric constant and high Curie temperature, respectively, in addition to their being lead-free materials. A thermal cycle test was carried out between RT and 600 °C, and clear multiple echoes were con?rmed during three thermal cycles for both materials. In addition, the sensitivity of CBiT/BiT was higher than that of CBiT/BST although a higher poling temperature is required for CBiT/BiT. Therefore, an ultrasonic transducer potential for high-temperature application was successfully demonstrated. ? 2018 The Japan Society of Applied Physics
关键词： ultrasonic transducer,high-temperature,sol–gel composites,lead-free,CaBi4Ti4O15
更新于2025-09-23 15:21:01