Enhancement Of Mechanical Properties Research Articles

Friction Stir Channeling in Heat Sink Applications: Innovative Manufacturing Approaches and Performance Evaluation

The fabrication of compact heat exchangers with precisely designed micro- and mini-channels is crucial for enhancing the efficiency of thermal management systems. Friction stir channeling (FSC) emerges as a cost-effective advanced manufacturing process to create complex integral channels, offering channel shape and size flexibility. This review article highlights the pivotal role of processing parameters in channel formation and maintaining their integrity, necessitating a comprehensive understanding of material flow dynamics. A rigorous assessment has been conducted on the channel under mechanical stresses, including tension, bending, and fatigue. The paper emphasizes the potential of FSC to revolutionize heat sink applications by exploring the fundamental concepts, governing parameters, ongoing enhancements in tool design, microstructural and mechanical properties, and heat transfer performance.

Formation of lamellar eutectic structure and improved mechanical properties of directional solidified Al0.9CoCrNi2.1 high-entropy alloy

In this study, Al0.9CoCrNi2.1 EHEA was prepared by directional solidification at various withdrawal rates from 6 to 120 μm/s. The lamellar eutectic structure is formed containing FCC (L12) and BCC (B2) at different withdrawal rates during directional solidification. The solid-liquid interface of the alloy transfers from nearly-planer to cellular eutectic interface and the lamellar spacing decreases from 7.17 μm to 1.65 μm as the withdrawal rate increases. The lamellar spacing is negatively correlated with withdrawal rates which was identified by the Jackson-Hunt model and its growth rate index (0.484) is closely related to the theoretical value (0.5). The tensile experiment demonstrates that the structure of Al0.9CoCrNi2.1 EHEA is finer and the ultimate tensile strength and elongation increase as the withdrawal rate increases. The elongation of Al0.9CoCrNi2.1 EHEA is two times higher than that of the as-cast alloy at the withdrawal rate of 120 μm/s. It is concluded that the formation of the L12 phase and Cr-rich precipitated phases in the directional solidified eutectic structure are associated with the enhancement of mechanical properties due to grain refinement at high withdrawal rates.

Optimized mechanical properties of the hot forged Ti–6Al–4V alloy by regulating multiscale microstructure via laser shock peening

The hot forged Ti–6Al–4V alloy demonstrates well constructed microstructure and balanced mechanical properties, which promotes its wide application in aviation field. However, its relative poor resistance to wear and foreign object impact usually leads to the cumulative damage, causing sudden failure and serious accident. Laser shock peening (LSP) is a novel surface plastic deformation technique, which could strengthen the surface layer of components through gradient grain structure. Nevertheless, the specific mechanism of microstructure evolution and mechanical properties enhancement of LSP processed hot forged Ti–6Al–4V alloy is still obscure, and its corresponding explanation would help the wide application. In the present research, the hot forged Ti–6Al–4V alloy was processed by LSP to regulate its superficial microstructure and improve mechanical properties, helping to understand the inner mechanism. The results reveal that LSP could simultaneously result in the merging of ultrafine α-Ti grains and refinement of coarse α-Ti grains, which reconstruct the dual-size grain structure. The crystal tilting and transformation promoted by the generation and movement of dislocations benefit the merging of ultrafine grains. Due to the different slip systems in dual phases, β-Ti phases exhibit much greater response to slip under surface plastic deformation, which are enforced to deform and construct the shell structure by sliding and phase transformation, while the α-Ti phases act as the core to synergistically construct ‘core-shell’ like structure. The increase of LSP impact time promotes the well wrapping of the ‘core-shell’ like structure and strengthens it by abundant dislocations, which also forms the gradient grain structure from surface to inner. Since the microstructure regulation and crystal defects engineering, the LSP improves the surface damage resistance and mechanical properties of the hot forged Ti–6Al–4V alloy obviously. Such results indicate a new technology to increase the properties of the hot forged Ti–6Al–4V alloy component further.

Improving the Interfacial Adhesion of Long Carbon Fiber-Reinforced Polyamide 6 Composites by Electrochemical Oxidation and Polyethylenimine-Carboxymethyl Cellulose Grafting.

Carbon fiber (CF)-reinforced thermoplastic composites have notable ascents in various sectors and applications. For high-performance composites, strong interfacial adhesion between the polymer matrix and the CF is crucial. This is achieved by introducing functional groups on the CF surface. In this paper, a water-based surface treatment was applied to long carbon fibers to enhance the interfacial bonding with the polyamide 6 (PA6) matrix. For that, PEI and CMC were grafted onto the surface of carbon fibers after electrochemical oxidation. The PEI-CMC sizing reduced the carbon fiber/water contact angle to 26.42° from 111.69°. The clear improvement in wettability resulted in a 164.8% increase in the interfacial strength of 26.7 MPa after the application of PEI-CMC sizing on carbon fibers (CFs). The resultant tensile and flexural strength increased by 19.3 and 11.7% from 2009.6 and 378.3 MPa for desized CF/PA6 composites to 250.3 and 422.7 MPa for PEI-CMC-sized CF/PA6 composites, respectively. Moreover, the fractured surface morphologies were also investigated to confirm the enhancement of mechanical properties. The proposed one-step electrochemical oxidation and water-based sizing procedure is found to be promising for the production of high-performance long-fiber-reinforced thermoplastic composites.

The mechanics of tissue-engineered temporomandibular joint discs: Current status and prospects for enhancement.

The temporomandibular joint (TMJ) disc is an essential protective but vulnerable fibrocartilage. Their high mechanical strength is vital in absorbing loads, reducing friction, and protecting the condylar surface. Many diseases can lead to the destruction or degeneration of the mechanical function of the TMJ disc. Unfortunately, conservative treatment is ineffective in restoring the defective mechanical properties of the discs. Tissue engineering has been investigated as a promising alternative treatment approach to approximate the properties of native tissue. However, it is difficult for tissue-engineered discs to obtain sufficient mechanical properties. Several approaches have been proposed to improve the mechanical properties of tissue-engineered constructs. In this review, we summarized the mechanical properties of native TMJ discs and discussed the current mechanical testing methods. We then summarized the current advances in improving the mechanical properties of TMJ disc tissue-engineered constructs. Moreover, existing challenges and outbreak directions are discussed. This review assists future research in better understanding the mechanical properties of both native and tissue-engineered TMJ discs. It provides new insights into future mechanical property enhancement for TMJ disc tissue engineering.

Fabrication and characteristics of functional hydrogels based on dopamine‐grafted gelatin and oxyglucan with incorporation of dipotassium glycyrrhizinate potential for wound dressings

AbstractHydrogel have been widely used to promote skin tissue regeneration and accelerate wound healing. The development of injectable hydrogels with multi‐functional integration is a priority, especially with antibacterial properties and cytocompatibility. Here, we reported a simple, and versatile method to fabricate a functional hydrogel with potential for wound dressing applications. The dopamine‐grafted gelatin (GT‐DA) and oxidized dextran (oxyglucan, ODex) were synthesized, and dipotassium glycyrrhizinate (DG) was in situ incorporated to fabricate the composite hydrogels (GDO) through the Schiff base reaction. SEM images revealed that hydrogel has a porous structure. By increasing the ratio of GT‐DA to ODex from 1 to 4, the storage modulus (G') and hydrogel network stability nearly doubled, reaching 900 Pa and 220% strain, respectively. The enhancement in mechanical properties could be attributed to the higher cross‐linking density resulting from increased Schiff base bonds in the GDO hydrogels. Furthermore, the GDO hydrogel exhibited antioxidant activity and antibacterial effects on Escherichia coli and Staphylococcus aureus. Moreover, the hydrogel demonstrated cytocompatibility after culturing with human umbilical vein endothelial cells (HUVECs). The results proved that the fabricated GDO hydrogels have the potential to be used as wound dressings.

Enhancement of Mechanical Properties of PCL/PLA/DMSO2 Composites for Bone Tissue Engineering

Bone tissue engineering shows potential for regenerating or replacing damaged bone tissues by utilizing biomaterials renowned for their biocompatibility and structural support capabilities. Among these biomaterials, polycaprolactone (PCL) and polylactic acid (PLA) have gained attention due to their biodegradability and versatile applications. However, challenges such as low degradation rates and poor mechanical properties limit their effectiveness. Dimethyl sulfone (DMSO2) has emerged as a potential additive to address these limitations, offering benefits such as reduced viscosity, increased degradation time, and enhanced surface tension. In this study, we investigate tailored composites comprising PLA, PCL, and DMSO2 to enhance mechanical properties and hydrophilicity. Through material characterization and mechanical testing, we found that the addition of DMSO2 led to improvements in the yield strength, modulus, and hydrophilicity of the composites. PCL and DMSO2 10, 20, and 30 wt% were premixed, and 20 wt% PCL + 10, 20, and 30 wt% DMSO2 were mixed with PLA. Specifically, PLA/PCL/DMSO2 composites exhibited higher yield strengths and moduli compared to pure PLA, pure PCL, and PLA/PCL composites. Moreover, the hydrophilicity of the composites increased with DMSO2 concentration, facilitating cell attachment. Fourier-transform infrared spectroscopy (FTIR) confirmed the presence of –COOH and –COH bands in PLA/PCL/DMSO2 composites, indicating chemical interactions between DMSO2 and the polymer matrix. Fractography analysis revealed enhanced interface adhesion in PLA/PCL/DMSO2 composites due to the hydrogen bonding. Overall, this study demonstrates the potential of PLA/PCL/DMSO2 composites in bone tissue engineering applications, offering improved mechanical properties and enhanced cell compatibility. The findings contribute to the advancement of biomaterials for additive manufacturing in tissue engineering and regenerative medicine.

Effects of recrystallization on interfacial microstructure evolution and shear strength of TiAl alloy joints

The effects of dynamic recrystallization (DRX) and post-bonding heat treatment (PBHT) on the interfacial microstructure evolution and mechanical properties enhancement of Ti-43Al-4Nb-1Mo-0.2B alloy joints, subjected to various bonding parameters, were thoroughly investigated through detailed microstructural characterization and shear performance tests. A strip-like DRX area was observed at the interface when bonding at 1100 °C, ≥30 MPa, for 60 min. Equiaxial- γ grains underwent discontinuous dynamic recrystallization during the bonding process, and tended to form flat grains parallel to the lamellae direction during recrystallization annealing (1000 °C/6 h) owing to the hindrance imposed by the lamellae on both sides. The orientations of lamellae on the both sides of bonding interface affects the lamellae's stress distribution and deformation behavior at the bonding interface, subsequently influencing the DRX behavior and the width of the DRX zone. Static recrystallization (SRX) during the recrystallization annealing treatment can eliminate bonding defects of joints bonding at lower pressures or temperatures. Optimal joints with fully lamellar interfacial microstructure and excellent shear properties can be obtained through single-α phase annealing treatment. Lamellae microstructure tailored through PBHT can significantly enhance the quality of joints, attributed to the homogeneity of the microstructure between the interface and matrix. The highest shear strength of 478 MPa, accounting for 82 % of the matrix strength, was obtained under the bonding parameters of 1100 °C/30 MPa/60 min-1290 °C/15 min. This work provides important DB process parameters for fabricating of complex structural parts of TiAl alloy.

Modification of the Structure and Mechanical Properties of Cu-30%Zn alloy with Cerium and Silicon

This study investigates how the introduction of cerium and silicon influences the structure and mechanical characteristics of Cu-30%Zn alloy. The examined properties included tensile strength, hardness, and impact resistance. The tensile strength of the developed alloys was determined using an automated JPL tensile strength tester (Model: 130812) with a capacity of 100 kilonewtons, following the ASTM D638 standard. The impact strength was assessed by the ASTM D256 standard using a pendulum impact testing machine (Model: U1820). Additionally, hardness testing was conducted using a Brinell tester. The Brinell hardness test was performed with a portable dynamic hardness tester (Model: DHT-6) by the British Standard (BS EN ISO 6505-1:2014). Specimens were prepared by incorporating cerium and silicon into the Cu-30%Zn alloy at concentrations of 0.1wt%, 0.3wt%, 0.5wt%, 1.0wt%, 3.0wt% 5.0wt% ranging from 0.1% to 5.0%, with increments of 0.2% for micro addition and 2.0% for macro addition. Microstructural analysis was performed using an L2003A reflected light metallurgical microscope. Scanning Electron Microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were also utilized to characterize the cast specimens. The findings revealed a proportional increase in tensile strength, impact strength, and hardness strength with the rise in dopant concentrations up to 3.0wt% for cerium and silicon. Also, the analysis uncovered the presence of. primary α-phase, β-phase (intermetallic phases), and fine stable phase. These phase modifications contributed to the enhancement of mechanical properties. Cu-30wt%Zn enriched with 3.0% cerium and silicon demonstrated heightened tensile strength, impact strength, and hardness, making it a recommended choice for engineering applications.

Advances and Significances of Nanoparticles as Concrete Additives: A Comprehensive Review

Nanotechnology, a significant technological advancement in the current century, has brought about revolutionary changes in numerous fields by manipulating matter at the nanoscale. This review paper examines the various applications of nanoparticles in the concrete industry, emphasizing their potential to improve mechanical qualities, thermal performance and sustainability. This study investigates multiple synthesis strategies, such as grafting, sol–gel, chemical and biological procedures, which offer concrete engineers a diverse range of options to tailor the properties of nanoparticles. The utilization of this particular material results in notable enhancements in many mechanical properties of concrete, including its compressive and flexural strength, toughness, thermal conductivity and self-sensing capabilities. These improvements ultimately contribute to the overall enhancement of the concrete’s structural integrity and energy efficiency. Adding nanoparticles to concrete has also been shown to help it develop self-healing properties. This means that structures last longer and require less maintenance. Making building materials more resistant to chemical corrosion, wear and environmental forces is also a big step in making them last longer. The growing emphasis on sustainability within the building industry has generated heightened attention toward utilizing self-healing concrete, which frequently incorporates nanoparticles. To make the building industry more environmentally friendly, using less traditional cement and recycling personal safety equipment (PPE) like vinyl and latex gloves can help protect the environment. This review also highlights the significant problems in employing nanoparticles in concrete: obtaining equal dispersion, handling-costs and addressing environmental and health concerns. However, nanotechnology is advancing construction concrete research to improve mechanical properties and durability.

Chondroitin Sulfate Derivative Cross-Linking of Decellularized Heart Valve for the Improvement of Mechanical Properties, Hemocompatibility, and Endothelialization.

Tissue-engineered heart valve (TEHV) has emerged as a prospective alternative to conventional valve prostheses. The decellularized heart valve (DHV) represents a promising TEHV scaffold that preserves the natural three-dimensional structure and retains essential biological activity. However, the limited mechanical strength, fast degradation, poor hemocompatibility, and lack of endothelialization of DHV restrict its clinical use, which is necessary for ensuring its long-term durability. Herein, we used oxidized chondroitin sulfate (ChS), one of the main components of the extracellular matrix with various biological activities, to cross-link DHV to overcome the above problems. In addition, the ChS-adipic dihydrazide was used to react with residual aldehyde groups, thus preventing potential calcification. The results indicated notable enhancements in mechanical properties and resilience against elastase and collagenase degradation in vitro as well as the ability to withstand extended periods of storage without compromising the structural integrity of valve scaffolds. Additionally, the newly cross-linked valves exhibited favorable hemocompatibility in vitro and in vivo, thereby demonstrating exceptional biocompatibility. Furthermore, the scaffolds exhibited traits of gradual degradation and resistance to calcification through a rat subcutaneous implantation model. In the rat abdominal aorta implantation model, the scaffolds demonstrated favorable endothelialization, commendable patency, and a diminished pro-inflammatory response. As a result, the newly constructed DHV scaffold offers a compelling alternative to traditional valve prostheses, which potentially advances the field of TEHV.

Investigation of the microstructure evolution and mechanical properties of cast Ti–47Al–2Cr–2Nb alloy during ultra-high pressure heat treatment

TiAl alloy is a high-temperature and lightweight material with superior properties, which has been widely used in aerospace industry. and casting is an economical method for its production. However, casting defects has hindered its direct applications in aerospace turbine blades. To minimize casting defects and achieve alloy strengthening, this paper proposed a novel single heat treatment process under ultra-high pressure (UHP) to regulate the microstructure and mechanical properties of the Ti–47Al–2Cr–2Nb alloy. The results indicated that the microstructure achieved overall grain refinement, high temperature and ultra-high pressure stresses jointly induced the γ→α2 phase transformation. After the UHP heat treatment, the hardness of the alloy increased from 287HV to 381HV, and the yield strength and ultimate strength increased by 53 % and 20 %, respectively, without significantly affecting the strain to fracture. Based on the phase transformation behavior and strengthening mechanism, these enhancements in mechanical properties were mainly attributed to the precipitation strengthening of α2 grains and the reduction of lamellar thickness. This suggested that UHP heat treatment was an effective method to improve cast TiAl alloys.

Mechanical properties of additively manufactured ultrafine grain stainless steel-titanium boride (SS–TiB2) nanocomposites

Stainless-steel, particularly the 316L alloy, is extensively utilized across diverse industrial sectors. Nonetheless, its inherent limitation of low yield strength poses a significant challenge. In this study, we propose a novel method to address this limitation by incorporating trace quantities of TiB2 nanoparticles into the 316L matrix. The methodology involves a combination of low-energy ball milling for the preparation of the powder feedstock, followed by selective laser melting (SLM) for the fabrication of nanocomposites. The resulting stainless-steel nanocomposite exhibits a nearly-full dense structure characterized by the uniform dispersion of TiB2 nanoparticles (30–40 nm in diameter) within the matrix grain interiors and at grain boundaries. This leads to a substantial refinement in the matrix grain and a remarkable enhancement in mechanical properties. Specifically, the incorporation of 3 vol% TiB2 nanoparticles results in substantial enhancements in tensile yield strength (90.5 %), microhardness (81.4 %), ultimate strength (78.03 %) and bulk modulus (75.2 %) at room temperature compared to plain SLMed stainless-steel. This notable enhancement arises from the uniform dispersion of TiB2 nanoparticles and grain refinement, achieved without discernible processing defects such as agglomeration or interface microcracks. These findings offer a promising avenue for enhancing the mechanical characteristics of stainless-steel-based nanocomposites, thereby expanding their applicability in demanding engineering environments.

Optimizing the rheological and mechanical properties of ultra-highly filled wood fiber/polyethylene composites through binary alloy matrix strategy

Enhancing the interfacial adhesion and rheological behavior of ultra-highly filled wood-plastic composites (UH–WPCs) presents a considerable challenge. We developed a bespoke binary alloy matrix of high-density polyethylene (HDPE) and maleated polyethylene (MAPE) to fabricate UH-WPCs with 70–90 wt% filler contents. Fourier-transform infrared spectroscopy and thermogravimetric analysis validated that about 22.3 % of MAPE engaged in esterification with wood fibers (WFs) in 80 wt% loading UH-WPCs, manifesting in noteworthy plasticization as evidenced by WFs' sheet-like structures. Rheological assessments illustrated that higher MAPE proportions reduced the viscosity of both the specialized alloy and UH-WPC melts significantly. By fine-tuning the MAPE to HDPE ratio to 16:2, we achieved marked enhancements in UH-WPCs' mechanical properties and dimensional stability: tensile strength and flexural strength increased by up to 141.7 % and 151.0 %, respectively, while creep strain and equilibrium water absorption decreased by as much as 27.3 % and 36.7 %. This research lays a robust scientific foundation for the efficient processing and enhancement of UH-WPCs, highlighting its potential for substantial improvements in mechanical performance, stability, and processability.

Metal ion-crosslinked thermoconductive sugar-functionalized graphene fluoride-based cellulose papers with enhanced mechanical properties and electrical insulation

Thermally conductive papers with electrical insulation and mechanical robustness are essential for efficient thermal management in modern electronics. In this study, we introduced a metal ion-assisted interfacial crosslinking strategy to strengthen sugar-functionalized graphene fluoride (SGF) and cellulose nanofibers (CNF) by hydrogen bonding and metal ion crosslinking that leads to simultaneous enhancements in thermal conductivity and mechanical properties. The facile sugar-assisted ball-milling exfoliation method was developed to achieve the exfoliation of graphite fluoride and hydroxyl group functionalization on the surface of graphene fluoride. Thanks to the good dispersibility of the SGF sheets in water, the flexible SGF/CNF composite papers with hydrogen bonding were prepared via vacuum-assisted filtration. We introduced hydrogen bonding and metal ion crosslinking into SGF/CNF papers to obtain densely packed composite papers. Ca2+ or Al3+ ion-crosslinked SGF/ CNF papers exhibited superior thermal and mechanical properties owing to hydrogen bonding and metal ion crosslinking. SGF/CNF-Ca2+ and SGF/CNF-Al3+ papers at 50 wt% of SGF yield in-plane thermal conductivities of 72.93 and 75.02 W m–1 K–1, and tensile strengths of 121.5 and 135.7 MPa, respectively. A thermal percolation value was observed at 12.6 vol% of SGF filler content. In addition, the SGF/CNF papers exhibited electrical insulation properties. These remarkable characteristics of the metal ion-crosslinked SGF/CNF papers are attributed to the densely packed structures caused by the strong interfacial interactions from hydrogen bonding as well as metal ion crosslinking that could promote phonon transport. High-performance metal ion-crosslinked SGF/CNF papers with these fascinating advantages offer great potential for the thermal management of flexible electronics.

Energy-saving approach for mechanical properties enhancement of recycled PET additively manufactured by MEX

This study investigates the recycling of polyethylene terephthalate (PET) water bottles by material extrusion (MEX), an additive manufacturing (AM) technique, with a focus on characterising energy consumption and mechanical properties throughout the recycling process. The process encompasses shredding of the bottles, filament production, and the printing of tensile specimens. A full factorial design of experiment (DoE) was used to investigate the impact of various process parameters on product quality from an energy-saving perspective. The results provide important insights into energy efficiency and mechanical performance, identifying the optimal production conditions that balance environmental sustainability and material functionality. The results show that by optimizing printing parameters, energy consumption can be reduced by up to 30%, while the tensile strength of the printed samples can be increased by 20%. This research contributes to a broader understanding of the potential for AM in PET recycling, providing a pathway towards more localized and sustainable manufacturing practices.

Effect of solidification pressure on the corrosion behavior and mechanical properties of Al-7Si-3Cu-(0.4 Mg)-(0.5Ge) alloys

Developing practical microstructural solutions that simultaneously enable excellent corrosion resistance and mechanical properties in Al-Si-Cu-based alloys has been increasingly in demand. In this study, we attempt to tailor the microstructural evolution to manipulate the mechanical performance and corrosion resistance of Al-7Si-3Cu-(0.4 Mg)-(0.5Ge) alloys fabricated by GPa-level pressure combined with solution and/or aging treatments. It was found that as the solidification pressure increased, the dendritic growth tendency of the α-Al phase became less pronounced, and the modification of eutectic Si became increasingly significant. Complete solid solution alloys were even achieved under 6 GPa. The corresponding kinetic and thermodynamic mechanisms of pressure-induced microstructural evolution were explored in detail. Upon aging treatment, dense irregular Si precipitates emerged from the supersaturated matrix in Al-7Si-3Cu alloys solidified at 5 GPa and 6 GPa, while denser and finer Si precipitates growing along the 〈100〉Al directions dominated the matrix of Al-7Si-3Cu-0.4 Mg-0.5Ge alloys, which resulted in considerable enhancement of mechanical properties. The electrochemical corrosion behavior was evaluated in the as-cast and heat-treated conditions. The underlying corrosion mechanisms were discussed in terms of pressure, supersaturated solutes and precipitates. These results reveal the feasibility of designing high-strength and corrosion-resistant Al-Si-Cu series alloys via the manipulation of pressure and heat treatment.

Dual role of two-dimensional graphene in silica aerogel composite: Thermal resistance and heat node

Incorporating two-dimensional graphene sheets, known for their high in-plane thermal conductivity, into silica aerogel enhances both the thermal insulation and mechanical properties of the composite. This work delves into the impact of graphene doping on the solid thermal conductivity of silica composites and their mechanical characteristics, employing molecular dynamics simulations that encompass both amorphous silica bulk and porous silica aerogel structures. Our findings reveal that graphene–silica interface thermal resistance notably restricts heat conduction in graphene doped silica aerogel, with the most pronounced effect occurring when graphene aligns vertically with the heat flux. Within porous silica aerogel, graphene serves as a “heat node”, bridging and connecting adjacent pores. A notable “trade-off” emerges: high weight percentages of graphene sheets augment heat transfer through the “heat node effect”, whereas the interfacial thermal resistance between graphene and aerogel reduces solid heat transfer, leading to decreased thermal conductivity. Additionally, while the inclusion of graphene sheets offers limited mechanical property enhancements, their two-dimensional structure can cause detachment and slipping from the silica matrix, leading to localized improvements in mechanical strength. This work sets the stage for advancing graphene-based aerogel composites characterized by low thermal conductivity and enhanced mechanical properties.

Alkali-activated composites with synthetic fibers and recycled aggregates: a study of mechanical properties

This study examines the potential for enhancing alkali-activated composites (AACs) through the incorporation of a blend of meta-zeolite (MZ) and slag, reinforced with synthetic fibers and incorporating aluminum sludge (AS) and recycled concrete aggregate. AACs were activated with sodium hydroxide (NaOH) and sodium silicate (Na₂SiO₃) in varying ratios and molarities (8M to 14M). The optimal mix, comprising 50% MZ and 50% S at 12M NaOH with 30% AS, exhibited notable enhancements in mechanical properties. Specifically, the addition of 0.5% basalt fibers resulted in a 7.26% increase in compressive strength and a 24.15% enhancement in flexural strength. These findings underscore the potential of MZ-S-based AACs, enhanced with aluminum sludge and basalt fiber, to develop advanced, sustainable construction materials. The study underscores the significance of optimizing material ratios and reinforcement strategies to achieve superior performance, thereby contributing to the development of environmentally friendly building solutions that align with contemporary standards.

Enhancement in mechanical properties of GFRP‐coal‐derived graphene oxide composites by addition of multiwalled carbon nanotubes and halloysite nanotubes: A comparative study

AbstractIn this study, we compare synergistic performance of two different nanofillers, namely halloysite nanotubes (HNT) clay and multiwalled carbon nanotubes (MWCNT), in conjunction with a fixed concentration (0.125 phr) of semi‐anthracite coal‐derived graphene oxide (AC‐GO) on mechanical properties improvement of EGFPs (E‐glass fiber‐based epoxy resin composites). The dispersion of AC‐GO with HNT clay (GO‐H) and AC‐GO with MWCNT (GO‐C) within epoxy matrix was achieved using sonication and homogenization. Further mixture was incorporated into mats of E‐glass fiber employing “vacuum‐assisted resin infusion molding” (VARIM). Significant enhancements (18.3% flexural strength, 14.6% tensile strength, and a slight increase of impact strength (1.8%)) were observed in EGFPs reinforced with GO‐H at 0.50 phr loading of HNT, with an AC‐GO concentration maintained at 0.125 phr. Correspondingly, optimal values for GO‐C reinforced EGFPs at 0.25 phr were 40.3%, 18.7%, and a 10.5% decrease in impact strength, respectively. Analytical techniques such as XRD, FESEM, EDX mapping, and FTIR reveal presence of relatively abundant functionalities and strong interfacial adhesion in GO‐H as well as GO‐C. The cost of HNT clay is approximately 15 times cheaper than industrial‐grade MWCNTs, therefore, these results underscore potential of GO‐H as a very economical nano‐reinforcement alternative to GO‐C for polymer nanocomposites.Highlights 0.50 phr HAGRP improves 18.3% flexural, 14.6% tensile, 1.8% impact strengths. Beyond 0.50 phr HAGRP and 0.25 phr CAGRP, mechanical properties decreased. 0.25 phr CAGRP improves 40.3% flexural, and18.7% tensile strengths. FESEM, FTIR reveal strong interfacial adhesion between nanofillers and epoxy. GO‐H has proven to be an inexpensive reinforcement for polymer nanocomposites.