Scanning Electron Microscopy Images Research Articles

Experimental study on the effect of filament-extrusion rate on the structural, mechanical and thermal properties of material extrusion 3D-printed polylactic acid (PLA) products

AbstractMaterial extrusion (MEX), also commonly referred to as fused deposition modeling (FDM) or fused filament fabrication (FFF) is currently one of the most commonly used additive manufacturing techniques. The quality of the 3D-printed objects fabricated by MEX methods highly relies on various printing parameters, one of which is the so-called filament extrusion multiplier (k). In this study, 3D-printed parts were prepared by MEX technique during which the material feeding rate was adjusted by varying the extrusion multiplier in the range of 97–105% (k = 0.97–1.05). The fabricated parts were tested for their geometrical, structural, mechanical, and thermal conductivity properties. Based on computed tomographic analysis and scanning electron microscopic images, increasing the k parameter resulted in smaller voids, along with gradually decreasing porosity (from 5.82 to 0.05%). Parallel to the decreasing defects, the thermal conductivity of the parts improved from 0.157 to 0.188 W/mK as determined by light-flash analysis technique. On the other hand, when k was set to ≥ 1.03 the geometrical accuracy declined, the size of the specimens considerably increased relative to the nominal values, especially in the X–Y directions due to excess material getting “squeezed” on the sides of the specimens. This latter phenomenon also resulted in the formation of a number of stress concentration sites, which manifested in the decrease of mechanical properties. Accordingly, the tensile, flexural, and impact strength of the samples improved up to k = 1.03; however, above that it dropped considerably.

Evaluation of long-term properties and life cycle assessment of alkali-activated concrete with varying fiber inclusions

The potential for using alkali-activated concrete (AAC) as a sustainable substitute for Portland cement (PC) concrete is a topic of ongoing research interest. The uncertainties in the raw material composition, the reportedly low tensile strength of AAC, and the lack of relevant standard codes of practice further inhibit wider industrial usage of AACs. Fiber inclusions reportedly enhance the tensile properties of traditional PC concrete. However, there is no long-term data available for fiber-reinforced alkali-activated concrete (FRAAC) mixtures. Hence, the present study is aimed at investigating the long-term mechanical properties of ambient-cured FRAAC with GGBS as the sole precursor. Four different types of fibers, viz., steel (SF), polyvinyl alcohol (PVAF), polypropylene (PPF) and glass (GF) are used in this research as reinforcements in AAC. Tests for compressive strength (fc′), splitting tensile strength (fsp) and flexural strength (fr) are conducted for FRAAC containing varying fiber contents of 0.1–0.3%. The findings demonstrated that fiber additions do not have any noticeable influence on the compressive strength of AAC. However, relative to the plain mix, the fsp and fr of FRAACs were enhanced by up to 32% and 29%, respectively. The formation of the hardened calcium aluminosilicate matrix and evolution of the fiber-matrix bonding over time was evident from the scanning electron microscopy (SEM) images. The related molecular bonds over a period of 7-d to 360-d was identified through mineralogical and chemical analyses. Furthermore, to validate its environmental sustainability, life cycle assessments were conducted. The AACs exhibited at least 43% lesser impacts than PC concrete on the ecosystem. FRAACs had only slightly higher (≤ 7% increase across all fiber types) impacts than plain AAC.

Influence of Programming and Recovery Parameters on Compressive Behaviors of 4D‐Printed Biocompatible Polyvinyl Chloride or Vinyl–Poly(ε‐Caprolactone) Blends

In this article, a new class of biocompatible shape‐memory polymers (SMPs) through blending pcolyvinyl chloride or vinyl (PVC) and poly(ε‐caprolactone) (PCL) is introduced. The compressive shape‐memory behaviors of 4D‐printed SMP PVC with 5 and 10 wt% of PCL are studied in detail. In this respect, a set of experiments are carried out to understand thermomechanical responses of PVC–PCL blends under various shape‐memory parameters like programming temperature, load‐holding time, applied strain, and recovery temperature. Dynamic mechanical thermal analysis and scanning electron microscope imaging are also performed to provide thermal and morphological analyses. It is found that by raising the recovery temperature from 45 to 65 °C, the shape recovery ratio increases from 5.63 to 7.92 MPa when the PVC–PCL10 is programmed via the hot‐programming (HP) protocol. The highest level of shape fixity (100%) and the best performance of stress relaxation are achieved for HP sample, while the highest shape recovery ratio (100%) is obtained for cold programming. By applying the load‐holding time, the amount of shape fixity can reach from 88.14% to 100%. Results of this research are expected to provide an insightful understanding of the shape‐memory behaviors of PVC–PCL and be instrumental for 4D printing and programming of shape‐adaptive structures like shape‐memory intervertebral cages as spinal support devices.

Quantitative Evaluation of the Pore and Window Sizes of Tissue Engineering Scaffolds on Scanning Electron Microscope Images Using Deep Learning

Quantitative Evaluation of the Pore and Window Sizes of Tissue Engineering Scaffolds on Scanning Electron Microscope Images Using Deep Learning

Optimization of the extrusion rate for different layer thicknesses to achieve controlled mechanical properties in MEX 3D printing of low-alloy steel

Composite extrusion modeling is an advanced material extrusion additive manufacturing process that requires fine-tuning of printing parameters for printing injection molding feedstocks. In order to achieve comparable high-quality parts at different layer thicknesses, the parameters must be optimized for the respective layer thicknesses. In this work, the printing parameters for AISI 8740 low-alloy steel injection molding material are optimized for four different layer thicknesses. The extrusion multiplier values for each layer thickness are tuned, allowing fine adjustment of the printer's screw rotation speed at every layer thickness, resulting in all final parts' maximum densities (≥ 98 %) with high accuracies. Scanning electron microscope images, surface roughness measurements, and printing precision tests proved the good and comparable high-quality of all optimized printed parts. Young's modulus, tensile and yield strengths also raised by ∼24 %, ∼16 % and ∼15 %, respectively, compared to the non-optimized printed sintered part. The achieved tensile strength range of (∼888–947) MPa and yield strength range of (∼574–586) MPa of all optimized printed sintered parts were also higher than those provided by the feedstock manufacturer. This promising approach significantly reduces printing time and manufacturing costs without compromising the printed final parts' quality and mechanical properties. The adjusting screw rotation speed methodology allows broader applicability across diverse material extrusion processes.

Effect of sodium hydroxide treatment on the fracture toughness of luffa natural fiber reinforced epoxy epikote 828

AbstractMicro‐sized luffa natural fibers (MLNFs) were derived from raw luffa natural fibers from Vietnam by undergoing treatment with sodium hydroxide. This study examined the impact of sodium hydroxide concentration, temperature, and treatment duration on the fracture toughness of epoxy resin 828 reinforced with MLNFs. The results showed that the fracture toughness of the composite, as measured by the critical‐stress‐intensity factor (KIC) and Izod impact strength, was improved after the treatment of the MLNFs with sodium hydroxide. Specifically, with the optimal sodium hydroxide treatment parameters of 6% NaOH at 70 °C for 6 h, the critical‐stress‐intensity factor increased by 93% (from 2.0 to 3.86 MPa m1/2) and the Izod impact strength rose by 44.6% (from 3.81 to 5.51 kJ/m2). The thermal properties and surface structure of MLNFs treated with NaOH were analyzed using thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) images.

Evaluating Recycled Concrete Aggregate and Sand for Sustainable Construction Performance and Environmental Benefits

This research investigates the potential of utilizing recycled concrete aggregate (RCA) and recycled sand (RS), derived from crushed concrete cubes, as sustainable alternatives in construction materials. The study comprehensively evaluates the properties of RCA and RS, focusing on workability, impact resistance, abrasion resistance, and compressive strength to determine their viability as substitute construction materials. A notable finding is RS’s enhanced fire and heat resistance when used as a fine aggregate in mortar blends, mixed with cement and Sinicon PP in a 3:1 ratio. The experimental analysis included thorough assessments of uniformity, durability, and curing time, alongside Scanning Electron Microscopy (SEM) for structural examination. Results show that RCA has an Aggregate Impact Value (AIV) of 5.76% and a Los Angeles Abrasion Value (LAA) of 21.78%, demonstrating excellent strength of the recycled aggregates. The mortar mix was also prepared using recycled sand, cement, and Sinicon PP, and its stability was confirmed through soundness tests, which resulted in a 0.53 mm expansion and a satisfactory consistency level of 44%. Ultrasonic pulse velocity (UPV) tests also indicated high-quality concrete formation using RCA and RS. SEM imaging corroborated this by revealing a bond between the cement paste and the aggregates. Incorporating RS and RCA in concrete mixtures impressively yielded a compressive strength of 26.22 N/mm2 in M20-grade concrete. The study concludes that using RCA and RS waste materials in the construction sector underlines that sustainable practices can be integrated without compromising material quality. This approach aligns with sustainable development goals and fosters a more environmentally friendly construction industry.

In vitro analysis of electrospun nanofibrous polycaprolactone loaded with Rhamnus prinoides leaf extract as potential wound dressing

AbstractRhamnus prinoides, an indigenous Ethiopian traditional medicinal plant, has been used for treating various ailments including skin conditions in traditional formulations. In this study, plant leaf extract has been incorporated into polycaprolactone (PCL) nanofibers through electrospinning at concentrations of 1%, 3%, 5%, 7% wt/vol for the first time. The presence of extract in the nanofiber was analyzed using Fourier transform infrared. The in vitro antibacterial activity, release, contact angle, thermal, and mechanical properties of the nano mats were characterized. The scanning electron microscopy (SEM) analysis revealed that the produced mats are continuous, smooth, bead‐less, and inter connected. The examination of SEM images using ImageJ revealed that the fiber diameter ranged from 219 ± 47 nm to 284 ± 114 nm. The mats showed excellent anti‐bactericidal activity against both Staphylococcus aureus and Escherichia coli. During the 72‐h in vitro release investigation, an initial burst release was observed within the first 12 h, followed by sustained release of the extract over long period of time. The contact angle analysis showed, addition of leaf extract to the PCL nanofiber increased hydrophilicity. Furthermore, the nanofiber membranes had favorable mechanical properties. Overall, these findings suggested that R. prinoides leaf extract‐functionalized PCL nanofibers could be effective wound dressings with broad‐spectrum antimicrobial activity.

Characterization of Bauhinia Variegata natural fiber treated with bleaching, benzoylation, and alkalization

This study describes the physical, chemical, mechanical as well as morphological characterization of surface modified novel Bauhinia Variegata (BVR) stem fibers. Surface modifications for the fiber are accomplished with bleaching, benzoylation, and alkalization treatments. Using standard test methods, the chemical constituents of BVR fiber are evaluated like α- cellulose 62.5%, hemicellulose 10.8%, lignin18.2% and wax 0.8%. Scanning electron microscopy (SEM) was used to see how different the chemical reactions affect the fiber and SEM images confirmed the enhanced rough surface and existence of voids, along with the subtraction of unusual substances from the fiber surface. In both treated as well as untreated BVR, a Fourier-transform infrared spectroscopy (FTIR) analysis established the presence of cellulose, hemicelluloses, and lignin components. X-ray diffraction test evaluated the crystalline index for treated and raw fiber. The thermogravimetric test provides proof of enhanced thermal sustainability in the BVR upon treating chemically. The increased tensile strength and Young’s modulus upon chemical treatment confirm the improvement in the mechanical properties of the BVR fiber. The moisture absorption test revealed that the hydrophilic nature of BVR was reduced after the chemical treatment, promoting greater fiber-matrix adhesion. Presently studied BVR fiber seems to be a good substitute to the harmful man-made fibers for making of bio composites.

An insight into viscosity and conductivity in the formulation of co-axial electrospun Carica papaya leaf extract

Objective: This research aimed to investigate the application of the coaxial electrospun method for the production of natural extracts (papaya leaf extract) fibre films. This was achieved through utilising different polymers and with a focus on the conductivity and the viscosity of polymer solutions as critical parameters to generate successful fibres.Significance: Electrospinning is a promising trending manufacturing method for incorporating thermolabile herbal extracts using coaxial electrospun features. However, the complexity of the electrospinning process and the feasibility of the product required precise scrutiny.Methods: The electrospinning solution parameters (conductivity and viscosity) were evaluated by employing various ratios of Eudragit L100 (EL100) and Eudragit L100-55 (EL100-55) pre-spinning polymeric blend solutions. The electrospinning process and ambient parameters were optimised. Following that, the in-silico physicochemical properties of phytochemical marker, rutin, were illustrated using SwissADME web tool. Both freeze-dried Carica papaya leaf extract and its produced films were characterised using Scanning Electron Microscopy (SEM), Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR), polarised light microscopy, and X-ray Powder Diffraction (XRPD).Results: The optimal values of conductivity (≈40–44 × 10−4 S/m) and viscosity (≈32–42 × 10−3 Pa·s) were determined for producing evenly distributed and small fibre diameters in SEM images. These parameters significance was highlighted in acquiring and maintaining adequate tangential stress for fibre elongation, which would consequently affect the morphology and diameter of the fibres formed.Conclusion: In conclusion, the solution, process, and ambient parameters are significant in developing natural extracts into films via electrospinning technology, and this includes the promising Carica papaya leaf extract films produced by coaxial electrospinning.

Properties of spray pyrolysis deposited Zr-doped ZnO thin films and their UV sensing properties

This study investigated the characteristics of Zr-doped ZnO thin films with varying Zr doping concentrations. X-ray diffraction (XRD) analysis confirmed the presence of the ZnO hexagonal phase without any additional phases detected. The crystallite size was determined using Scherrer’s equation and Halder-Wagner equation, revealing distinct trends as the Zr content increased. The impact of Zr doping concentration on structural properties such as lattice parameters was also explored. Field emission scanning electron microscopy (FE-SEM) images indicated agglomeration, with a peak value observed at Zr-5 wt% of 175 nm that decreased at higher Zr contents. Optical properties exhibited minor variations with increasing Zr content, with the maximum band gap recorded at 3.28 eV for Zr-7 wt% and Zr-10 wt% films. Utilizing the Spitzer-Fan model, the high-frequency dielectric constant peaked at 14.26 for Zr-7 wt% films. Optical mobility displayed fluctuations with rising Zr content. Direct current (DC) conductivity results unveiled two donor levels in the deposited films, showcasing minimum activation energies of 0.23 and 0.165 eV for high and low-temperature ranges in the Zr-3 wt% film. Furthermore, the response to UV light illumination at a wavelength of 365 nm was examined, revealing notable changes in rise and decay times with varying Zr content.

Scanning electron microscopic investigation on Chicory tribe (Compositae) botanical sources and their antimicrobial potential.

This study discusses the micro-level structural details of Cichorieae pollen sources elucidated by scanning electron microscopy (SEM) and explains their symmetry and morphometry. The in-depth knowledge from the electron ultrastructure of Asteraceae pollen has provided insights into enhanced pollen morphology, and the antimicrobial significance of species under study presents novel avenues for their natural defense mechanisms in the development of antimicrobial agents. In this research, both quantitative and qualitative features of pollen were examined. The pollen grains are prolate-spheroidal and oblate-spheroidal in shape, characterized by a maximum polar diameter of 55.6-61.0 μm and a maximum equatorial distance of 68.3-74.4 μm. SEM reveals various configurations such as echinate perforate-tectate, psilate, and echino-lophate perforate. The Cichorieae species have significant antimicrobial efficacy and are promising sources for the development of novel antimicrobial drugs with potential implications in pharmaceutical and healthcare industries. SEM analysis of Cichorieae pollens has provided remarkable insights into their unique structures, revealing diverse shapes and surface ornamentations, which can be used for accurate Asteraceae species identification. RESEARCH HIGHLIGHTS: SEM provides unique pollen surface structures and patterns of Chicory pollen grains. Chemical composition of Chicory botanical sources provides valuable information on their potential as antimicrobial agents. SEM imaging reveals specialized fenestrate grain structures of taxonomic importance.

Evaluating nickel removal efficacy of Filtralite under laboratory conditions: Implications for sustainable urban drainage systems

Our study deals with the critical issue of heavy metal pollution in urban runoff; we focused particularly on the threat posed by heavy metals such as nickel to living organisms and water resources owing to their toxicity at low concentrations and non-biodegradability. In this study, we evaluated the efficacy of Filtralite, a filtration medium with excellent hydraulic properties, in removing nickel from water through laboratory experiments and advanced simulation tools. We analysed the geochemical processes involved in nickel removal, including precipitation and adsorption. Importantly, we implemented an innovative approach for numerical modelling using HP1, by combining HYDRUS-1D and PHREEQC for modelling solute transport in porous media and geochemical reactions, respectively. The experimental results revealed that the Filtralite-laden column achieved a removal efficiency of 93.5 % for injected nickel. We observed a significant increase in the effluent pH from 7.0 to 11.5 during the interaction with Filtralite, affecting the solubility of the nickel phases. The model showed the highest nickel concentration in the initial column layers because of rapid chemical precipitation and adsorption upon contact with Filtralite. High-resolution scanning electron microscopy images confirmed the presence of amorphous precipitates around the soil particles, aligning with the changes in pH. This study contributes significantly to environmental engineering and urban water management by introducing an innovative numerical model in HP1 to accurately simulate the removal of nickel using Filtralite. These findings validate the efficiency of Filtralite in extracting nickel from aqueous solutions. Thus, Filtralite is a strong candidate for inclusion in sustainable urban drainage systems.

Experimental analysis of 3D printed continuous carbon/glass hybrid fiber reinforced PLA composites: Revealing synergistic mechanical properties and failure mechanisms

AbstractThis study investigates the mechanical properties of continuous carbon/glass hybrid fiber‐reinforced polylactic acid (PLA) composites (HFRC) produced through the three dimensions (3D) printing process, comparing them with single carbon fiber‐reinforced PLA composites (CFRC). Initially, composite prepreg filaments are prepared using an impregnation device, followed by fabrication using a 3D printer. The mechanical performance results reveal a 13% increase in tensile strength for HFRC compared with CFRC. Due to differing elongation rates of carbon and glass fibers, HFRC exhibits two strength peaks, while CFRC demonstrates a 37% higher bending strength than HFRC. Scanning electron microscope images indicate that the tensile failure mechanism involves fiber brittle fracture and fiber‐matrix interface debonding, while the bending failure mechanism includes fiber pullout, fiber debonding, fiber cluster buckling, and interlayer interface failure.Highlights To realize the moldless rapid manufacturing of continuous hybrid fiber‐reinforced PLA composites. The stress–strain curves of single fiber‐reinforced composites and hybrid fiber‐reinforced composites are obviously different. Elucidating the effect of single fiber/hybrid fiber in composites on mechanical properties and failure mechanism according to micro‐morphology.

Impact of filler type and proportion on the performance of rubberized coconut fiber-polystyrene composites

Abstract This research investigates the production of composite materials by utilizing a polystyrene-based resin (PBR) as the matrix and a blend of coconut fiber (CF) and rubber tire (RT) as fillers. The composites were produced in varying proportions, and their mechanical and chemical properties were characterized through hardness tests, Fourier-Transform Infrared Spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) analyses. The findings highlight the notable influence of filler type and proportion on the mechanical and chemical attributes of the composites. The hardness tests demonstrated a substantial enhancement in composite hardness with the incorporation of CF and RT fillers, with CF exerting a more pronounced effect. FTIR analysis disclosed the presence of aromatic and aliphatic groups in all composites, and the introduction of CF and RT particles led to the emergence of additional peaks. EDS analysis indicated that carbon was the predominant element in all composites, followed by oxygen, while the SEM images revealed a heterogeneous microstructure for all composites, with good dispersion of CF and RT particles in the PBR matrix. The resulting composites exhibit potential applications in diverse fields such as construction, automotive, and packaging.

Investigation of biomimetic HAp formation on graphite

According to reports, coating implants with hydroxyapatite (HAp) promotes bone repair and combines the biological effectiveness of the material with the mechanical properties of standard metallic implants. In this contribution, bioactive nanographite particles were synthesized using a novel technique to stimulate HAp deposition using a biomimetic method. The rapid breakdown ionization (RBA) technique was used to synthesize graphite nanoparticles. The electrophoretic deposition (EPD) technique was utilized to deposit the nanoparticle on titanium substrates. Scanning electron microscope (SEM) images showed the creation of nanoparticles with a size of around 65nm. An X-ray diffraction (XRD) test confirmed the polycrystalline structure of graphite with a dominant peak (002). UV-VIS absorption and FTIR spectra confirmed the production of graphite powder. To test the bioactivity of the graphite layer, it was immersed in simulated body fluid (SBF) for 30 days. The formation of a HAp layer on graphite is depicted by an XRD pattern, and SEM images illustrate nanoclusters of this layer.

ODIFICATION OF PINDIGA BENTONITE CLAY WITH DIDODECYLDIMETHYLAMMONIUM BROMIDES SURFACTANT FOR FOUNDRY USE

Bentonite clay from Pindiga, Gombe State, Nigeria, was surface modified with didodecyldimethylammonium bromides (DDAB) by the Base Exchange (cation exchange capacity) method for its possible use in foundries. The surfaces of the unmodified and modified Pindiga bentonite clay were characterised by means of spectroscopic, diffraction, and scanning methods (X-Ray fluorescence spectrometry (XRF)Fourier-transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM).XRF showed that unmodified sample was rich of montmorillonite (MMt) with ca +2 as exchangeable cation, FTIR analysis revealed that unmodified water absorption causes stretching and bending vibrations for hydroxyl groups, with the most intense bands in the low-frequency region, while DDAB organo-bentonites showed slight changes in wave bands, with a strong methyl band and a weak methyl band indicative of long-chain linear aliphatic structure. The basal spacing of the unmodified bentonite sample was 1.52 nm, and after modification with DDAB, it improved to 2.1 nm as determined from the X-ray diffraction (XRD) analysis. Results of the SEM images revealed rougher surfaces with uniformly dispersed small particles of grain-like structures characteristic of the unmodified, while theorgano-modified bentoniterevealed clusters of different sizes and shapes, larger Fe 3+ ions replacing smaller Al 3+ ions at octahedral sites, discontinuous layers enveloping large grains, polygonal growth foams with octahedral and tetrahedral shapes, mixed layers of calcium bentonite, and particle sizes less than 200nm. The study concluded that modified bentonite with didodecyldimethylammonium bromides gives good microstructure, increases rigidity, and improve thermal stability, to the organoclays. Therefore, it is recommended that DDAB bentonite be used as binder for foundries.

Effect of Ga doping on the structural, optical, and electrical properties of ZnO nanopowders elaborated by sol-gel method

Nanostructured ZnO has received a considerable amount of interest, owing to its unique physical and chemical characteristics, as well as its remarkable performance in the fields of electronics, optics, and photonics. This work aims to study the influence of Ga dopant on the structural, optical, and electrical properties of ZnO nanopowders. Undoped and Ga-doped ZnO (GZO) nanopowders were successfully synthesised with the soft chemical sol-gel method. The solution was prepared using zinc acetate dihydrate and gallium (III) nitrate hydrate as precursors. The ethylene glycol is used as solvent. The X-ray diffractometer, scanning electronic microscope (SEM), UV–Vis, FTIR, and four-point probe method are used to analyse the properties of the synthesised powders. XRD and FTIR measurements show the growth of pure and Ga-doped ZnO crystals, which have a hexagonal wurtzite structure, and the average crystallite size varies from 9.09 nm to 24.8 nm. The nanospherical morphology of the nanopowders synthesised can be seen in the SEM images. The UV–visible spectroscopy shows that the optical gap energy increases with Ga concentration, from 3.59 eV to 3.67 eV. The I-V electrical measurements indicate that the breakdown voltage and the non-linear coefficient increase with Ga doping. This study will open the way for the investigation of a relationship between the electrical and nanostructural features of ZnO-based varistors for future device applications.

A Review: Characterization Of Aluminium-Metal Matrix Composite Reinforced with Zirconium Diboride

Composite materials with aluminium matrices are used in thermal management, defence, aerospace, automotive and aviation. As the prices of useful items decreased, their usefulness increased. Aluminium is reinforced with other metals, non-metals and ceramics to give it the required physical and mechanical properties such as high tensile strength, great hardness and corrosion resistance. Aluminium-metal matrix composites are known for their exceptional physical and mechanical properties and performance. This work also focuses on the fabrication and characterization of zirconium diboride reinforced aluminium-metal matrix composite. Zirconium diboride particles were used as reinforcement material to fabricate aluminium metal matrix composites by the stir casting method. The microstructure, hardness and tensile strength of aluminum-metal matrix composites and its corrosion behaviour were investigated. The results showed that the inclusion of zirconium diboride particles increased the hardness and tensile strength of aluminum-metal matrix composites. Field emission scanning electron microscopy and x-ray diffraction analysis are used to investigate the microstructural properties of aluminum-metal matrix composites reinforced with zirconium diboride particles. Field emission scanning electron microscopy images showed a uniform distribution of zirconium diboride particles in the aluminum-metal matrix composites matrix. X-ray diffraction analysis showed the formation of an intermetallic compound of aluminium and zirconium diboride. From the review that have been made, we can conclude that the inclusion of zirconium diboride particles increased the mechanical properties and corrosion of aluminium-metal matrix composites.

Nested structure role in the mechanical response of spicule inspired fibers.

Euplectella aspergillum marine sponge spicules are renowned for their remarkable strength and toughness. These spicules exhibit a unique concentric layering structure, which contributes to their exceptional mechanical resistance. In this study, finite element method simulations were used to comprehensively investigate the effect of nested cylindrical structures on the mechanical properties of spicules. This investigation leveraged scanning electron microscopy images to guide the computational modeling of the microstructure and the results were validated by three-point bending tests of 3D-printed spicule-inspired structures. The numerical analyses showed that the nested structure of spicules induces stress and strain jumps on the layer interfaces, reducing the load on critical zones of the fiber and increasing its toughness. It was found that this effect shows a tapering enhancement as the number of layers increases, which combines with a threshold related to the 3D-printing manufacturability to suggest a compromise for optimal performance. A comprehensive evaluation of the mechanical properties of these fibers can assist in developing a new generation of bioinspired structures with practical real-world applications.