Enhancement Of Tensile Strength Research Articles

Influence of sub-zero coolant circulation and additive nanoparticles on performance characteristics of FSPed Al6061 alloy

ABSTRACT Al6061 alloy has become prevalent in the industrial sector because of its low density, excellent machinability, and corrosion resistance but it lacks properties like hardness and wear. Therefore, surface modifications by friction stir processing (FSP) are done with additive nanosized particles like multi-walled carbon nanotubes (MWCNT), Titanium oxide (TiO2), and Graphene nanoparticles (GNP) To perform 2-pass FSP, a uniquely engineered fixture with coolant circulated underneath the plate at sub-zero temperatures is used. Grain refinement has been observed in micrographs as a consequence of 2-pass FSP. The coolant circulated beneath carries the heat generated and enhances the heat dispersion rate, culminating in finer grains. The calculated mean grain size of the Al6061 alloy was considerably decreased in all the surface composites. There is a substantial improvement in the microhardness profile, which has increased by nearly 70–90%, as well as a significant enhancement in tensile strength of almost 20–30% in all the composites. The ductile type of failure during tensile load is revealed by SEM fractography. The process of dynamic recrystallisation is responsible for the development of equiaxed grains. The wear resistance of all the composites is also enhanced, and the COF of Al6061/GNP composite is found to be lowest at 0.23.

Hydrotalcite-Enhanced Tough and Strong Hydrogel Endowed by Coordination and Electrostatic Interactions for Both Strain and Pressure Sensors.

Polymer hydrogels have a wide range of applications in the field of flexible wearable devices from the perspective of easy commercialization and environmental compatibility. However, traditional hydrogels often fail to achieve adequate mechanical strength and performance such as toughness, resilience, and ionic conductivity. Herein, a significant enhancement of tensile strength in 2 orders of magnitude (from 36 kPa to 1.5 MPa) is obtained by the introduction of hydrotalcite into polymer network via multiple, multilevel, and strong interactions of strengthened interface interactions, and the enhancement effect is superior to most of known records. Meanwhile, the enhanced conductivity may be rationally attributed to effective channels of hydrotalcite for ion transport. As a result, high toughness (9.5 MJ/m3), stretchability (1520%), excellent resilience (100% rebound of 400% strain), high conductivity (2.6 mS/cm), and low-temperature resistance are successfully achieved. The work shows an efficient approach to design desired ultratough and multifunctional hydrogels.

Optimization of friction stir processing parameters to improve mechanical properties and microstructure of Al5083 aluminum alloy reinforced with AlCoCrFeNiSi high-entropy alloy

Abstract This study explores integrating AlCoCrFeNiSi high-entropy alloy (HEA) particles into the Al5083 aluminum alloy matrix via Friction Stir Processing (FSP) to enhance mechanical characteristics. Microstructural analysis reveals a homogeneous distribution and size reduction of HEA particles, contributing to improved structural strength. X-ray diffraction (XRD) examination confirms the formation of solid solution phases in the HEA particles, validating their role in enhancing material properties. Through the utilization of Design of Experiments (DOE) and Response Surface Methodology (RSM), FSP parameters are systematically optimized, enabling precise predictions of mechanical behavior. Multi-response optimization identifies the optimal combination of FSP parameters, resulting in significant enhancements in Ultimate Tensile Strength (UTS) and Hardness, reaching 314 MPa, 42% elongation, and 75 HV, respectively. Scanning Electron Microscopy (SEM) analysis of tensile test specimens elucidates the impact of varied FSP parameters on microstructural features, emphasizing the importance of optimal mixing for improving interfacial bonding and mechanical properties. This study underscores the effectiveness of integrating HEA particles and optimizing FSP parameters to elevate the mechanical properties of Al5083 aluminum alloy, paving the way for tailored composite materials with enhanced performance for specific applications.

A microwave-assisted, solvent-free approach for effective grafting of high-permittivity fillers to construct homogeneous polymer-based dielectric film with high energy density

Polymer-based dielectric film capacitors are essential energy storage components in high-power energy storage devices benefiting from their high breakdown strength (Eb) and ultra-fast charge storage/release capability. However, the state-of-the-art commercial capacitor, biaxially oriented polypropylene (BOPP), exhibits limited energy storage density primarily due to low dielectric constant, which hinders the advancement of the film capacitor industry. Introducing high-permittivity (high-k) nanofillers into PP matrix to improve polarization is a promising method but poor filler dispersion leads to a remarkable decrease of Eb, while various strategies to enhance dispersion of fillers typically require sophisticated process involving toxic procedure and consuming significant time and cost. Herein, we show that a novel and scalable surface grafting method for high-k fillers can be achieved by a facile and short-period microwave irradiation with the assistance of silane coupling agent (KH560). As a demonstration, the KH560 is effectively grafted onto the surface of barium titanate (BT), achieving a high grafting ratio of 4.91 % at a yield of 85.1 % within a short time (40s). Furthermore, the surface modified BT nanofillers are introduced into PP matrix and then biaxially stretched. The as-prepared film exhibits excellent dispersion and superior compatibility, resulting in a remarkable enhancement of tensile strength (from 82 MPa to 115.4 MPa), breakdown strength (from 200 MV/m to 254 MV/m), and energy density (from 1.49 J/cm3 to 2.21 J/cm3). This work proposes a new strategy for constructing homogeneous polymer-based dielectric film by microwave activating high-k fillers and is crucial for the design of next-generation energy storage devices.

Elucidating the effect of cyclic plasticity on strengthening mechanisms and fatigue property of 5xxx Al alloys

The strength of non-heat-treatable 5xxx Al alloys is derived from solid solution strengthening and strain hardening, the absence of a precipitation strengthening response results in their lower strength. In this study, significant improvements in strength can be achieved by subjecting three different Mg concentrations 5xxx Al alloys to cyclic plasticity. A quantitative analysis of the respective contributions to the yield strength has been conducted by combining transmission electron microscopy and atom probe tomography. Additionally, the fatigue performance and fatigue mechanism of the cyclic strengthened 5xxx Al alloys have been thoroughly studied due to its transformation from non-heat-treatable to precipitation strengthening. We demonstrate that the high-cycle fatigue (HCF) strength of the cyclically strengthened state only experiences a minor improvement compared to the as-received state, which is significantly disproportionate to the enhancement in tensile strength. This disparity is primarily attributed to the changes in microstructure and fatigue mechanisms, resulting in a reduction in fatigue ratio. This study provides important insights for expanding research on cyclic plasticity methods in fatigue performance, and can aid in the development of improved processes for optimal fatigue resistance.

Sustainable use of recycled fine aggregates in steel fiber-reinforced concrete: Fresh, flexural, mechanical and durability characteristics

Recycling construction waste is a viable tactic for advancing environmentally friendly building methods. With regard to concrete applications, the purpose of this research is to determine whether it is feasible to use recycled fine concrete aggregates (RFA) in lieu of natural fine aggregates (NFA) and to lessen the environmental impact of natural resource depletion and landfill space. A sustainable steel fiber-reinforced concrete was created by replacing NFA with RFA at the replacement ratio of 0 %, 50 %, and 100 %. Steel fibers (SF) were also included to mixes at three different contents of 0, 25 and 50 kg/m3 in order to further improve the qualities of the concretes. Thus, the aim of this paper is to appraise how the addition of FRA affects the mechanical, freeze-thaw, fresh, and non-destructive qualities of concrete. Nine concrete mixtures were cast, and tests were made to evaluate the following properties: flowability, fresh concrete unit weight, tensile and compressive strengths, elastic modulus, surface hardness, crack mouth opening displacement (CMOD), freeze and thaw performance, sulfate resistance and abrasion. Moreover, microstructure properties of concrete were also analyzed. The outcomes revealed that the mechanical, flexural, and durability performances of the concrete mixtures were enhanced by substituting RFA for NFA. The mixture with 50%RFA and 50 kg/m3 SF gained maximum compressive strength of 44.82 MPa which was 20.7 % greater than the reference mixture (RFA0F0). The mixture containing 100 % RFA and 25 kg/m3 SF had the highest elastic modulus and showed an approximately 33 % augmentation in elastic modulus as per the reference mixture. The mixture with 100%RFA and 50 kg/m3 SF exhibited the largest tensile strength indicating 60 % tensile strength enhancement as per the reference mixture. Combined use of RFA and 50 kg/m3 SF in concrete mixtures had the best abrasion and freeze-thaw resistance. SF incorporated concrete mixtures with RFA exhibited worse sulfate resistance. This study contributed significantly to global resource efficiency and environmental preservation by shedding light on the sustainable use of RFA and SF in the making of concrete. The results made important contributions to global research and promote environmentally friendly building methods all throughout the world.

Creating ultra-strong and recyclable green plastics from marine-sourced alginate-chitosan nanowhisker nanocomposites for controlled release urea fertilizer

In response to the pressing environmental challenge posed by petroleum-derived plastics, the development of green plastics derived from all-biomass nanocomposites offers promising solutions. However, conventional nanocomposites often prioritize enhanced stiffness at the expense of flexibility. We introduce sodium alginate (SA)/chitosan nanowhisker (CSW) nanocomposites, derived entirely from marine-sourced all-biomass, to create ultra-strong and flexible green plastics. Through the synergistic interaction between SA and CSW, these nanocomposites demonstrate simultaneous stiffening and toughening, overcoming the traditional trade-off. Two key mechanisms contribute: geometric reinforcement from the needle-like structure of CSW and electrostatic reinforcement at the interface between oppositely charged CSW and SA. Compared to control SA, the SA/CSW nanocomposites exhibit remarkable enhancements in tensile modulus, strength, and stretchability, by 49 %, 85 %, and 55 %, respectively (7.6 GPa, 223.3 MPa, 14.7 %). Cellulose nanocrystals, serving as a control, only stiffen the nanocomposites, adhering to the typical trade-off. Biodegradability in compost can be tailored based on the type of nanofillers. Due to the water resistance of CSW, SA/CSW nanocomposites are proven effective for the controlled release of urea fertilizer in agricultural applications. With recyclability and superior mechanical properties, these marine-sourced green plastics offer a sustainable alternative to conventional plastics, promising significant impact in the eco-plastic industry.

Influential reinforcement parameters, elemental mapping, topological analysis and mechanical performance of lignocellulosic date palm/epoxy composites for improved sustainable materials

The value of biomaterials for green products has begun to develop more ecofriendly and renewable sustainable materials for a better circular economy and to reduce carbon footprints. This work presents integrated investigations of the lignocellulosic date palm/epoxy composites at various reinforcement condition parameters for sustainable structural materials where elemental mapping, topological analysis, and mechanical performance have been performed. Mapping energy dispersive X-ray spectroscopy was utilized to assess the composite composition properly. Elemental mapping and a scanning electron microscope were employed to evaluate the chemical composition of the composites. The mechanical performance of the produced composites was also explored in terms of ultimate tensile strength, tensile modulus, elongation at break, and impact energy properties. The effects of fiber loading, fiber length, and fiber width (as long fiber, short fiber, and long-thin fiber) were investigated for the date palm fiber/epoxy composites. Results have revealed that the composite behavior was affected by several influential reinforcement parameters. The energy dispersive X-ray spectroscopy maps by C–K, O–K, Si–K, K-K, and Ca-K demonstrated that the composites contain mainly carbon, silicon, and oxygen. It was evident that the modulus of elasticity property of short fiber composites exhibits an increasing trend with higher fiber content, even at 35 wt%. Moreover, the enhancement of tensile strength for the short fiber size composites reached 72.5 %. However, such tensile strength of thin fiber size/epoxy composites achieved 135.7 % at 25 wt% indicating superior development of this mechanical property. The long date palm fiber composites demonstrated the best value of modulus of elasticity and the maximum impact energy of 15.3 kJ/m2 attained at 25 wt%, which is about 112.5 % enhancement. Scan electron microscope was capable of confirming that broken fibers were not separated from the matrix indicating the good adhesion between the fiber and the matrix that supports their good mechanical performance.

Mechanical and Dynamic Mechanical Characterization of Epoxy Composites Reinforced with Casuarina Leaf Bio Fibre

This study investigates the influence of casuarina leaf biofibre on the mechanical and morphological characteristics of epoxy resin composites. Composites were prepared using the hand-layup method, incorporating varying volume fractions of the biofibre (4%, 8%, 12%, 16%, 20% and 24% v/v). Mechanical and dynamic mechanical tests were carried out to assess the impact of the biofibre on the composite material. Mechanical testing revealed significant enhancements in tensile strength of 29.2 MPa, particularly at a biofibre volume fraction of 12% and the composite with the highest impact and flexural strengths measured at 2621 J/m2 and 41.1 MPa, respectively for the 16%v/v fibre loading. Dynamic mechanical analysis (DMA) results demonstrated improved viscoelastic properties attributed to the presence of the biofibre. Scanning electron microscopy (SEM) examination of tensile tested samples provided insights into interfacial bonding and filler dispersion within the composite matrix. Overall, the findings highlight the potential of casuarina leaf biofibre to enhance specific mechanical properties and viscoelastic behaviour of epoxy casuarina composites. Optimizing the biofibre volume fraction offers possibility to tailor composite properties for specific application requirements. This research advances the development of bio-based composite materials, contributing valuable insights for the creation of sustainable and high-performance engineering materials.

Poly(vinylidene fluoride-trifluoroethylene)/graphene composite pressure sensors and their potential applications in sports training

Pressure sensors based on advanced materials have gained high attention for their potential applications in various fields, including sports training. This study focuses on the development of poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE))/graphene composite films as high-performance pressure sensors. The composite films were fabricated using a casting method, and their morphological, structural, thermal, mechanical, and electrical properties were comprehensively characterized. The incorporation of graphene nanoplatelets (GnPs) into the P(VDF-TrFE) matrix led to the formation of a percolated conductive network, resulting in enhanced electrical conductivity and pressure sensitivity. The composite film containing 5 wt% GnP exhibited remarkable sensing capabilities, boasting an elevated sensitivity of 0.85 kPa−1, a rapid response time of 50 ms, and exceptional resilience over 1000 loading-unloading cycles. Moreover, the incorporation of GnP substantially augmented the mechanical properties, with a 65 % enhancement in tensile strength and a 92 % surge in Young's modulus when juxtaposed against pristine P(VDF-TrFE) films. The superior property of these P(VDF-TrFE)/graphene composite pressure sensors, along with their excellent mechanical properties, make them promising candidates for sports training applications, enabling the monitoring and analysis of various biomechanical parameters to optimize athletic performance and prevent injuries.

A NOVEL DOUBLE-SIDE LASER WELDED THICK PLATE: MICROSTRUCTURE AND NUMERICAL PREDICTION OF TENSILE TEST

The study aims to provide firsthand knowledge on finite element simulation (FES) of double-side laser welded (LW) stainless steel 304 (SS-304) thick plates used for automobile application. Double-side welding technique is an idea of achieving complete penetration with minimal heat input. The microstructural evaluation revealed the presence of dendritic growth that results in the enhancement of tensile strength (TS) for the welded sample. There is a slight increase in the delta ferrite content in weldment. The change in microstructure is due to thermal history during solidification. The TS of base metal (BM) was [Formula: see text][Formula: see text]MPa whereas the welded sample exhibited strength of [Formula: see text][Formula: see text]MPa. FES was successfully employed to simulate TS with error percentage less than 1.

Synergic effects of silica aerogel (SA) particles on tensile behavior of cryo-conditioned epoxy: The role of particle morphology and mixing sequence

Cryogenic conditions are of crucial importance for gas storage tanks to provide increased storage density, reduced pressure requirements and minimized energy losses. Incorporation of silica aerogel (SA) particles as a nanostructured material with extremely low density and exceptional thermal insulating properties into epoxy matrices has the potential to facilitate the progress of high performance nanocomposite coatings for advanced cryogenic applications. The objective of this study is therefore to investigate the impacts of particle size, particle content, milling method and mixing sequence on toughness of the cryo-conditioned epoxy coatings. SA particles of varying size (50 μm to 300 μm) were prepared using two different techniques (planetary ball milling vs. 2-blade grinding). Nanocomposite samples were prepared using two distinct mixing sequences, i.e., adding particles (in 0, 0.5, 1 and 1.5%wt.) to epoxy followed by mixing with hardener or adding particles to epoxy/hardener (with 3 or 15 min delay). The nanocomposite samples were subjected to different cryogenic conditions (single 3-h immersion in liquid nitrogen vs. three consecutive 1-h immersions). Mechanical properties of the samples were evaluated by conducting fractography, dynamic mechanical thermal analysis (DMTA) and tensile tests. Large SA particles settled towards the bottom of nanocomposite and resulted in loss of mechanical properties at cryo-conditions. Mixing 1 wt% of optimized SA particles with epoxy/hardener system led to an enhanced tensile strength (26 %), stiffness (3 %) and toughness (71 %) by providing uniform cross-linking reactions and mitigating thermal shock effects at cryo-conditions. Toughening mechanisms included crack deflection, crack pinning, crack arrest and crack branching.

Construction of tree-ring mimetic 3D networks in polyvinyl alcohol/boron nitride composites for enhanced thermal management and mechanical properties

Constructing a three-dimensional (3D) filler network in polymer thermal interface materials (TIMs) is crucial for enhancing thermal conductivity and mechanical properties. However, the discontinuous and loose network of fillers are one of the main reasons hindering the joint improvement of thermal conductivity and mechanical properties. The construction of a regular and dense 3D continuous filler network remains a significant challenge. In this study, an innovative bidirectional freezing technique was designed to create a polyvinyl alcohol (PVA)/boron nitride (BN) composite with a tree-ring-like 3D network. This technique promotes the formation of 3D network consisting of long-range lamellar BN layers with a tree-ring-like structure by controlling the nucleation and growth of ice crystals along the bidirectional temperature gradient induced by a polytetrafluoroethylene (PTFE) cone. The resulting PVA/BN composite exhibits high thermal conductivity (6.25 W/m·K) due to the lower interfacial thermal resistance between fillers (1.271 × 10−7 K m2/W), and an enhanced tensile strength of 41.71 MPa, which is attributed to the regular and dense BN network. This study presents a feasible strategy for constructing a 3D continuous network structure in polymer-based TIMs, paving the way for advancements in thermal management solutions.

Tensile and flexural strength enhancement in carbon‐fiber epoxy composites using a novel method of particle type electrophoretic deposition of carboxyl functionalized graphene on carbon fiber

Tensile and flexural strength enhancement in carbon‐fiber epoxy composites using a novel method of particle type electrophoretic deposition of carboxyl functionalized graphene on carbon fiber

Photocuring 3D printable flexible strain sensor enhanced by in situ grown silk fibroin nanoparticles

The growing demand for flexible strain sensors across diverse applications necessitates elevated standards regarding the outstanding mechanical performance and customizability of their polymer-based substrates. In this study, the ionically conductive gels with in situ generation of silk fibroin nanoparticles (SFN) for photocuring 3D printing were successfully designed. The silk fibroin underwent chain folding as a result of phase separation with the photocurable resins (PCR), leading to the direct in situ generation of nanoparticles within the PCR. The results demonstrated a significant improvement in the stability of liquid PCR/SFN and the mechanical performance of ionogels prepared via the in situ SFN growth method, manifesting a notable enhancement in tensile strength and elongation at break by 340% and 62.8%, respectively. Moreover, reliable loading behavior was maintained under large strain conditions of 600% tensile strain and 50% compressive strain throughout long-term cycles, accompanied by stable signals. The customization, stability, and sensitivity of sensing behavior were achieved through the fabrication of customized porous-structured flexible sensor components from the PCR/SFN system, including a series of finger, wrist, and throat sensors, as well as an insole gait sensor. The facile strategy of in situ SFN growth could be an effective approach for manufacturing nanocomposite conductive ionogels, offering new avenues for modulating the mechanical performance of 3D-printed flexible strain sensors.

Influence of Recycled Coarse Aggregate and Steel Fiber on the Workability and Strength of Self-Compacting Concrete

Abstract Waste materials pose a significant threat to both the environment and human health. On a global scale, the quantity of recyclable material is steadily growing, and its proper disposal is a significant focus of modern study. Concrete debris is a recyclable material that poses challenges for reutilization. Concrete waste refers to the fragments or remains of ready-mix concrete plants and the debris from destroyed structures, including historic buildings and those affected by earthquakes. The objective of this study is to reuse and utilize coarse aggregate formerly used in concrete constructions to create self-compacting concrete (SCC). The purpose is to assess the performance of this recycled aggregate in both its fresh and hardened states. Natural coarse aggregate (NCA) was switched out for recycled coarse aggregate (RCA) at 0, 50, and 100% volume ratios. In contrast, concrete was mixed with steel fibers (SF) at volume percentages of 0 and 0.44. Workability tests, including V-funnel, slump flow, and L-box tests, were conducted to assess the consistency of the mixes in their fresh condition. Additionally, the tensile and compressive strength of the concrete specimens were measured to evaluate their strength in the hardened state. Overall, the experimental findings showed that the fresh qualities of almost all SCC mixes fell within the required range, as outlined in the EFNARC standards. While the steel fiber harmed the fresh characteristics, it resulted in a proportionate enhancement in tensile strength. The findings indicated that including recycled aggregates into the concrete mixture enhanced its strength. The results showed that adding (0.44%) of steel fibers to concrete reduced the decline in compressive strength when the coarse aggregate was replaced entirely with recycled aggregate. In contrast, an equivalent proportion of fibers resulted in a significant improvement in tensile strength, rising from 26% to 54%, when using recycled coarse aggregate as the replacement of natural coarse aggregate. Thus, it can be concluded that using recycled aggregates and steel fibers in concrete production results in a higher quality product than regular concrete. Removing concrete waste has other benefits, such as enhanced financial return and preservation of the environment.

Study on the mechanical and thermal properties of aramid fibre reinforced with sawdust particulates in an epoxy matrix composite: a novel material for structural applications

AbstractThis study investigates the development and characterization of a novel composite material for structural applications, aiming to address the growing demand for lightweight, durable and versatile materials. The composite integrates aramid fibre reinforced with sawdust particulates within an epoxy matrix. Methodologically, the composite was fabricated using a hand layup process, ensuring even distribution and strong adhesion between components. Mechanical testing revealed significant enhancements in tensile strength (up to 135.29 MPa) and flexural strength (up to 136.92 MPa) with the inclusion of sawdust particulates, optimizing stress distribution and impact resistance. Hardness was also improved, peaking at a Rockwell hardness number of 94. Thermal analysis demonstrated moderate thermal conductivity (1.92 W mK−1) and a high heat deflection temperature (109 °C), indicating excellent thermal stability. SEM provided insights into the composite's microstructure, confirming uniform sawdust distribution and robust fibre–matrix adhesion. These findings underscore the potential of this composite for lightweight, durable and thermally stable structural applications. © 2024 Society of Chemical Industry.

Enhancement of anti-oxidation and tensile strength of nanotwinned Cu foils by preferential Ni electrodeposition

In this study, Ni was employed to enhance the mechanical properties of nanotwinned copper (NT-Cu) foils due to its excellent oxidation resistance and compatibility with Cu. The tensile strength of the NT-Cu foils was enhanced 12.6 % (752.8 to 847.3 MPa) by Ni co-electrodeposition. During the electroplating, it was found that Ni ions inhibited the Cu growth, causing the reduction potential (overpotential) to shift in the negative direction. It resulted in a reduced deposition rate and decreased the twin spacing of the foils. Additionally, Ni ions acted as impurities for the grain refinement. Time of flight secondary ion mass spectrometry (TOF-SIMS) results indicated that Ni atoms were deposited on the top and bottom of the foils due to the limiting current density of Ni. The NT-Cu-Ni exhibited low roughness and performed superior resistance to oxidation compared to the NT-Cu. X-ray photoelectron spectroscopy (XPS) was also utilized to characterize the oxidation of the Cu (Ni) alloys. These mechanisms contributed to high strength, low resistivity, and excellent oxidation resistance of the NT-Cu-Ni foils for future battery materials.

Bio-coloration and Antibacterial Function of Wool grafted with pomegranate peel polyphenols catalyzed by laccase

With the deterioration of environmental problems and world energy consumption, the improvement of textile dyeing has been paid more and more attention by researchers. The application of natural dyes in the dyeing of wool fabrics had become a research hotspot. However, the main drawback of the application of natural dyes lies in the poor color stability on wool fabrics. Therefore, research on environmentally and economically friendly dyeing processes has gained crucial importance. In this paper, the effect of pomegranate pigment on the functional dyeing of wool fabric under the catalysis of laccase was discussed. The dyeing effect of different methods on wool fabric was compared and the laccase catalytic dyeing process was optimized. Firstly, the properties of pomegranate peel pigment were analyzed by Ultraviolet-visible absorption spectrum (UV-Vis) and Fourier infrared spectroscopy (FTIR). Then the surface morphology and properties of wool fabric were observed by scanning electron microscope (SEM), microscope and FTIR. Lastly the function and stability of dyed wool fabric were tested by color characteristic value, UV resistance, antibacterial property, color fastness and tensile strength. The results showed that better dyeing effect of wool fabric were obtained by dyeing firstly with pomegranate peel and then catalysis with laccase. The optimum process of laccase catalysis was as follows: catalysis time 8 h, laccase dosage 3.3 U, temperature 50℃, pH 5. The results of SEM, FTIR and microscope tests showed that the phenolic compounds in the pigment of pomegranate peel was catalyzed by laccase to form the deepened coloration polymers and the phenolic polymers were finally combined with the wool fabric. Laccase-catalyzed dyed wool fabric showed good performance stability, such as color fastness to rubbing and soap-washing, strong antibacterial property, great enhancement of UV resistance and excellent tensile strength. The application of laccase in the natural dyeing process of textiles can provide a better way to improve the dyeing properties.

Enhancement of Tensile Strength of Coconut Shell Ash Reinforced Al-Si Alloys: A Novel Approach to Optimise Composition and Process Parameters Simultaneously

The research presents a novel approach to develop high-strength functionally graded composite materials (FGCMs) by using recycled coconut shell ash (CSA) particles as reinforcement for a hypereutectic Al-Si alloy matrix. Using a centrifugal casting technique, test specimens are prepared for the study under ASTM standards. The optimal combination of materials to maximise the materials’ overall tensile strength is obtained through the mixture methodology approach. The results show that CSA particles in the matrix material increase the tensile strength of the produced material. Process parameters, melting temperature and rotating speed were found to play a pivotal role in determining the tensile strength. A better tensile strength of the material is obtained when Al-Si = 90.5 wt%, CSA = 9.5 wt%, rotating speed = 800 RPM, and melting temperature = 800 °C; the proposed regression model developed has substantial predictability for tensile strength. This work presents a methodology for enhancing the tensile strength of FGCMs by optimising both the material composition and processing parameters. The achieved tensile strength of 197.4 MPa, at 800 RPM and 800 °C, for a concentration of 7.5 wt% CSA particles, makes these FGCMs suitable for use in multiple engineering sectors.