Enhancement Of Mechanical Properties Research Articles

Enhancement of Mechanical Properties and Freeze–Thaw Durability of Recycled Aggregate Concrete using Aggregate Pretreatment

Enhancement of Mechanical Properties and Freeze–Thaw Durability of Recycled Aggregate Concrete using Aggregate Pretreatment

Development of rare earth element-based hybrid aluminium composites using stir casting process.

Aerospace and marine industries are constantly in search of materials that can provide good strength and durability while also being lightweight. Aluminium composites with adequate reinforcements have been proven to be effective in achieving incredible mechanical properties while also maintaining a good strength to weight ratio. Numerous studies have been done to study the various possibilities of matrix reinforcement combinations in aluminium composites. This work focuses on studying the effect of varying Cerium Oxide (CeO2) percentage in the aluminium composite on its tensile strength, hardness and corrosion resistance. CeO2 is used along with Silicon Carbide (SiC) and Multi-Walled Carbon Nanotubes (MWCNT) to develop four samples of hybrid aluminium composites with SiC and MWCNT constituting 1% and 0.1% of the composite and the weight percentage of CeO2 is varied between 1 and 2.5%. All the samples were fabricated using the modified stir casting process. The results show that the hardness and tensile strength of the composites peak when the CeO2% is at 2% while corrosion resistance only gets better with increasing reinforcement content. A significant enhancement in mechanical and physical properties of aluminium composite suggests that MWCNT is an effective hybridizing agent with SiC and CeO2 to develop aluminium composites.

THE EFFECT OF HEAT-TREATMENT ON THE MECHANICAL PROPERTIES OF EXPANDED GLASS PARTICLE/A356 SYNTACTIC FOAM

This research investigates the manufacturing of metal syntactic foams (MSFs) using a packed bed of porous (2-2.8 mm) expanded glass (EG) within an A356 alloy matrix. To this end, the counter-gravity infiltration casting technique is employed to manufacture the specimens. The density of the MSFs ranges from 1.05 to 1.17 g/cm3, making it one of the lowest densities foams, attributed to the filler particles' low bulk density. The study investigates the influence of T6 heat treatment on the mechanical properties and microstructural characteristics of the manufactured MSFs. The mechanical properties of the MSFs are characterized under quasi-static compressive loads at 1 mm/min. After heat treatment, the compression test results indicate a significant enhancement in most mechanical properties. Compression strength and plateau stress are approximately doubled compared to as-cast foams for samples with similar densities. While energy absorption of the MSFs triples in heat-treated conditions. These improvements are attributed to changes in the matrix microstructure due to thermal treatment. Microstructural analysis reveals that Si particles, initially sharp and continuous within inter-dendritic boundaries, become blurry and discontinuous through spheroidization after thermal treatment. This hinders crack growth in the cell wall and mitigates the effects of casting defects and the columnar dendritic structure. The majority of mechanical properties in both heat-treated (HT) and as-cast (AC) foams exhibited an increase in density due to an increase in the matrix fraction. However, plateau end strain and energy absorption efficiency demonstrated an independent effect of heat treatment and density.

Analysis of stress-strain curve of POM fiber reinforced concrete

ABSTRACT As a new type of synthetic fiber, polyoxymethylene (POM) fiber has the advantages of high tensile strength, good dispersibility, and high bonding strength with cement interface. It has broad application prospects. However, there is limited research on POM fiber reinforced concrete. In order to provide scientific basis for promoting the application of POM fiber, this paper adopts a combination of indoor experiments and numerical simulations to obtain the axial stress-strain complete curves of POM fiber reinforced concrete with different volume dosages and studies the uniaxial compressive properties of POM fiber reinforced concrete. Finally, the constitutive equation parameters of POM fiber reinforced concrete were fitted using the Guo Zhenhai model, and the optimal fiber content was determined. The results indicate that at a POM fiber content of 1.5 kg/m3, the load-displacement curve exhibits optimal shape with the highest residual strength. With increasing fiber content, compressive stress-strain curve parameters initially increase and then decrease, peaking at 1.5 kg/m3, optimizing the mechanical properties of concrete. POM fiber has minimal impact on initial elastic modulus. Thus, optimal mechanical property enhancement is achieved with 1.5 kg/m3 POM fiber content.

Density Modifications Toward High Mechanical Performance Nanocellulose Aerogels

ABSTRACTMechanical properties are crucial for the application of nanocellulose aerogels. In this work, a series of nanocellulose aerogels with solid content concentration gradient (0.5, 1.0, 1.5, 2.0 wt%) of precursor dispersion are prepared by freeze‐drying method, and the effect of nanocellulose solid content on the mechanical properties of nanocellulose aerogels was investigated. As the solid content concentration increased, the internal microstructure of the aerogel underwent a transition from a sparse reticular structure to a tightly arranged lamellar structure. This transition led to a substantial improvement in the mechanical properties of the aerogel. At 50% strain, the compressive strength of the aerogel increased from 8.4 to 37.56 kPa with the increase of nanofibrillar cellulose solid content. Furthermore, the specific strength, specific modulus, and compressive modulus also increased, while maintaining a low density (20.02 mg/cm3) and high porosity (98.63%). This work confirms the feasibility of structural strengthening and mechanical property enhancement of nanocellulose aerogels by density modification, which provides a guidance for the design of durability enhancement of nanocellulose aerogels for broadening their application fields.

Mechanical properties of poly(ethylene succinate) thin films incorporated with chemical synthesis copper oxide nanoparticles

This study investigates the synthesis and characterization of poly(ethylene succinate) (PES) thin films and their composites with copper oxide (CuO) nanoparticles. CuO nanoparticles were synthesized using a chemical synthesis method, achieving an average size of 20 nm. PES/CuO composites were prepared by incorporating CuO at various concentrations of 0, 1, 3, and 5 wt%. The thin films were produced through solution polymerization followed by casting. Mechanical testing revealed that the tensile strength of pure PES was 25 MPa, while incorporating 1 wt% CuO increased the tensile strength to 30 MPa. At 3 wt%, the tensile strength reached 35 MPa, and at 5 wt%, it peaked at 40 MPa, demonstrating a significant enhancement in mechanical properties. The elongation at break also improved, increasing from 200% for pure PES to 250% for the 5 wt% CuO composite. Characterization of the materials was performed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) to analyze structural and morphological properties. The results confirm that the PES/CuO composites exhibit enhanced mechanical properties, indicating their potential for diverse applications in sustainable materials and biomedical fields.

Surface metamorphosis techniques for sustainable polymers: Optimizing material performance and environmental impact

The transition to sustainable polymers is crucial for reducing the environmental footprint of additive manufacturing, particularly in fused deposition modeling (FDM). This study investigates surface metamorphosis techniques—methods to modify polymer surfaces at micro and nanoscale levels to enhance performance and minimize environmental impact. We explore plasma treatment, chemical etching, and laser texturing on biodegradable and recycled polymers, assessing their effects on surface properties, such as adhesion, roughness, and chemical resistance. Our results demonstrate significant enhancements in mechanical properties. For example, PLA’s tensile strength increased from 55.3 MPa (untreated) to 63.8 MPa (plasma treated), and its elongation improved from 4.2% to 5.1%. PHA showed a similar trend, with tensile strength rising from 45.1 MPa to 52.6 MPa, and elongation increasing from 5.6% to 6.4%. rPET and rPP also exhibited improvements, indicating the effectiveness of these surface treatments. Employing a multi-criteria decision-making approach, we assess and prioritize these techniques based on their mechanical enhancements and sustainability profiles. While this study presents hypothetical results, it establishes a comprehensive framework for optimizing surface metamorphosis processes, guiding future experimental research. Our findings suggest that tailored surface modifications can significantly improve the performance and environmental sustainability of polymers in FDM, offering pathways for integrating eco-friendly materials into advanced manufacturing. This work contributes to the development of green manufacturing technologies by highlighting surface metamorphosis as a key strategy for achieving high-performance and sustainable materials.

Innovative early age mechanical properties of 3D printable mortar enhanced with SBR latex and kaolin

As the global population has continued to grow, the costs and environmental issues associated with traditional construction materials like cement and river sand have become increasingly problematic. This study explores the innovative enhancement of early-age mechanical properties of 3D-printable mortar through the incorporation of Styrene-Butadiene Rubber (SBR) latex and kaolin. Various sands (Lawrencepur, Chenab, and Ravi) were tested at 120 min for compressive stress, direct shear strength, Young’s Modulus, and Shear Modulus. Lawrencepur Sand exhibited the highest compressive stress (206.75 kPa) and shear strength (74.60 kPa), followed by Chenab Sand and Ravi Sand. Young’s Modulus values were highest in Lawrencepur Sand (7.93 MPa), indicating superior stiffness, while Shear Modulus was highest in Chenab Sand (3.79 MPa). Ravi Sand, despite lower mechanical strengths, was found optimal for printable mortar due to its fine particle size and desirable texture. The incorporation of SBR latex and kaolin resulted in reduced maximum deflection and enhanced load-bearing capacity over time, with Lawrencepur Sand containing 99.64% sand particles and minimal silt bearing the ultimate load effectively. This study highlights the potential of SBR latex and kaolin in improving the early-age mechanical properties and suitability of sands for 3D-printable mortar, providing a balance between mechanical performance and printability.

Enhancement of Mechanical Properties of Geopolymer Ferrocement through Incorporation of a Novel Binder and through Optimization of Alkaline Activator Ratios

Geopolymer ferrocement is geopolymer mortar, reinforced with wire mesh. The ratios of binder composition and alkaline activator, with which the geopolymer has been prepared, have profound influence on the mechanical performance of geopolymer ferrocement. In this study the influence of a binder material Alccofine and variation in ratios of alkaline activators have been studied for their effect on mechanical properties of geopolymer ferrocement. Alccofine was replaced with varying proportions of Ground Granulated Blast-Furnace Slag (GGBS). The molarities of NaOH and NaOH/Na₂SiO₃ ratios were also variated to find their influence on strength and crack control of ferrocement, when combined with single, double, and triple-layers of ferro mesh configurations. Tests such as direct shear test, three-point bending, and four-point flexural tests were conducted to to measure shear strength, flexural strength and to estimate region of pure bending. It was observed that the mix with 20% Alccofine and 80% GGBS, an A/B ratio of 0.5, and a NaOH/Na₂SiO₃ ratio of 1.5 yielded a compressive strength of 50 MPa at 90 days of geopolymer ferrocement. Also the triple-layer mesh configuration exhibited the best results, achieving 10 N/mm² in shear strength and 12 N/mm² in flexural strength, compared with other configurations. These findings indicate that by incorporation of Alccofine, optimizing binder composition, activator ratios and reinforcement, the strength parameters of geopolymer ferrocement can be significantly improved.

In-situ synthesis of Yttria-based precipitates and their effects on Fe12Cr6Al in laser powder bed fusion

To advance the suitability of FeCrAl alloys for nuclear applications, radiation damage resistance, creep resistance, corrosion resistance, and mechanical properties enhancement are essential. A promising approach is the introduction of a high density of nitride and oxide nanoprecipitates within the alloy matrix. This study aimed to explore the impact of in-situ formed nitride and oxide precipitates on the properties of Fe12Cr6Al alloy by using a nitrogen-rich atmosphere and incorporating nano-sized Y2O3 (0.45 wt. %) during laser powder bed fusion (LPBF). As a result of adding Y2O3 nanoparticles to the Fe12Cr6Al alloy, the grain size decreased from 70 μm to 40 μm, and the Al-O, Al-N, and Al-N-O precipitates were replaced by Y-O, Y-Al-O, and Y-N precipitates. Additionally, the nitrogen contents increased from 220 ppm to 470 ppm. The sample with Y2O3 exhibited higher mechanical properties, with yield strength, tensile strength, and hardness (HV) increasing by 80 MPa, 112 MPa, and 23 HV, respectively. This study deviates from previous research on Y2O3-containing FeCrAl alloys by investigating the impact of in-situ synthesized Y-N nitrides on Fe12Cr6Al. The objective is to elucidate the combined effects of these precipitates on the properties of Fe12Cr6Al alloy in comparison to literature-reported oxide dispersion-strengthened (ODS) FeCrAl alloys, which were fabricated in an argon (Ar) atmosphere.

Chirality Manipulation of 3D Printed Gyroidal Scaffolds towards Mechanical Properties Enhancement

Chirality Manipulation of 3D Printed Gyroidal Scaffolds towards Mechanical Properties Enhancement

Green synthesis of multifunctional natural rubber-lignin nanocomposites: A sustainable approach for waste reduction

Lignin, a valuable biomaterial having an array of exciting properties is increasingly favoured as a reinforcement material in the fabrication of green composites. Reinforcement in biopolymers like natural rubber (NR) using lignin nanoparticles (LNP) is considered a hotspot today. In this study, LNP synthesized via the homogenization method was incorporated into natural rubber latex (NRL) using probe sonication, and NR/Lignin nanocomposites (NR/LNP) were fabricated using latex dipping method. The addition of LNP resulted in significant enhancements in mechanical and antibacterial properties, biodegradability, and ultraviolet (UV) blocking capabilities with the addition of 7 parts per hundred rubber (phr) of LNP, due to the uniform dispersion and effective interaction between NR and LNP. This research demonstrates a versatile pathway for integrating LNP into NR through a green method, enabling the production of eco-friendly NR nanocomposites for multifunctional applications. This pathway contributes to a safe disposal of NR based products.

Enhancement of mechanical properties of natural rubber latex sheets by incorporating allyl-modified microcrystalline cellulose (AMCC)

Microcrystalline cellulose (MCC) was chemically modified with allyl bromide through the hydroxyl groups of cellulose to obtain allyl-modified microcrystalline cellulose (AMCC). To enhance the curing and mechanical properties of natural rubber latex, this AMCC was then compounded with a natural rubber latex formulation to produce rubber sheets. Unmodified MCC was also compounded and prepared into rubber sheets, which served as a reference. The formation of AMCC was confirmed using Fourier Transform Spectroscopy (FTIR). Furthermore, the thermal behavior of AMCC was examined by thermogravimetric analysis (TGA), and the degree of crystallinity before and after modification was evaluated by X-ray diffraction (XRD). The results of the rubber sheets showed that overall, maximum torque (MH), degree of crosslinking density, vulcanization rate (cure rate index), and tensile strength increased in AMCC-loaded rubber compared to MCC-loaded sheets. On the other hand, optimum cure time (t90) and elongation at break were lower in the AMCC-loaded rubber than in the MCC-loaded sheets. In overall, this method outlines a successful incorporation of modified cellulose into natural rubber-based products to obtain enhanced mechanical properties.

Enhancement in Mechanical Properties of AA5052 Sheet for Small Ship by Cold Roll-Bonding Process

A cold roll-bonding (CRB) process was applied to enhance the mechanical properties of AA5052 sheet for small ship. Two and four AA5052 sheets of 1 mm thickness, 40 mm width and 300 mm length were stacked, then roll-bonded to a thickness of 0.5 mm and 1 mm respectively by two-pass rolling after such surface treatment as degreasing and wire brushing. The rolling was performed at ambient temperature without lubricant using a 4-high mill at rolling speed of 6.0m/sec. The as roll-bonded AA5052 sheet was then annealed for 1h at various temperatures from 200 to 500℃. The as roll-bonded AA5052 sheets showed a deformation structure in which the grains are elongated to the rolling direction, however above 300℃ they exhibited the complete recrystallization structure consisting of equiaxed grains, regardless of the stack number. The grain diameter of specimens annealed at high temperatures above 300℃ was smaller in 4-layer stack than in 2-layer stack CRB. Both tensile strength and elongation of the specimens were better in 4-layer stack than in 2-layer stack CRB. The effects of stacking number on microstructure and mechanical properties of AA5052 sheets processed by CRB and subsequent annealing were discussed in detail.

Tuning of the mechanical properties of a laser powder bed fused eutectic high entropy alloy Ni30Co30Cr10Fe10Al18W2 through heat treatment

Eutectic high entropy alloys (EHEA) with an exceptional combination of strength and ductility are promising candidates as advanced structural materials. However, achieving an optimal balance between the properties in additively manufactured EHEAs is an outstanding challenge. In this work, Ni30Co30Cr10Fe10Al18W2 EHEA was additively manufactured using the laser powder bed fusion (LPBF) technique. In the as-fabricated state, it exhibits a dual-phase nano-lamellar structure consisting of FCC/L12 and B2 phases. Post-fabrication heat treatments were explored for modulating microstructure and, in turn, enhancing the mechanical properties, so as to achieve an optimum balance between strength and ductility. Upon heat treatment at 750 °C for 1 h, part of the B2 phase transformed into FCC, with the appearance of the tungsten-rich precipitates inside the B2 phase. The average interlayer spacing of the FCC/L12 lamellae increased to 124 nm, while that of B2 lamellae decreased to 86 nm, resulting in an alloy with an ultimate tensile strength (UTS) of 1811 MPa, although the strain to failure (εf) decreased to 2 %. Upon increasing the heat treatment temperature to 1000 °C, the average interlayer spacings of the FCC and B2 phases increased to 210 and 187 nm, respectively, which resulted in a more balanced mechanical behavior with UTS and εf of 1332 MPa and 9.3 %, respectively. This study provides an effective approach for microstructural modulation and enhancement of mechanical properties of LPBF fabricated EHEA via post-fabrication heat treatment, offering insights for developing future high-performance alloys for advanced structural applications.

Influence of Al and Ti Alloying and Annealing on the Microstructure and Compressive Properties of Cr-Fe-Ni Multi-Principal Element Alloy

This study meticulously examines the influence of aluminum (Al) and titanium (Ti) on the genesis of self-generated ordered phases in high-entropy alloys (HEAs), a class of materials that has garnered considerable attention due to their exceptional multifunctionality and versatile compositional palette. By meticulously tuning the concentrations of Al and Ti, this research delves into the modulation of the in situ self-generated ordered phases’ quantity and distribution within the alloy matrix. The annealing heat treatment outcomes revealed that the strategic incorporation of Al and Ti elements facilitates a phase transformation in the Cr-Fe-Ni medium-entropy alloy, transitioning from a BCC (body-centered cubic) phase to a BCC + FCC (face-centered cubic) phase. Concurrently, this manipulation precipitates the emergence of novel phases, including B2, L21, and σ. This orchestrated phase evolution enacts a synergistic enhancement in mechanical properties through second-phase strengthening and solid solution strengthening, culminating in a marked improvement in the compressive properties of the HEA.

Study on enhancing mechanical and thermal properties of carbon fiber reinforced epoxy composite through zinc oxide nanofiller

This study investigates the enhancement of mechanical and thermal properties of carbon fiber reinforced epoxy composites by incorporating zinc oxide (ZnO) nanofillers. The composites were developed by adding 3–15 g of ZnO nanoparticles into the epoxy matrix and were evaluated through experimental testing. The results showed significant improvements in mechanical performance, with the maximum tensile strength of 112.49 MPa and flexural strength of 114.82 MPa at the 15 g ZnO concentration. SEM analysis revealed a reduction in void content and improved fiber-matrix adhesion, enhancing load transfer. Thermal conductivity is 13.47 W/mK, while the coefficient of linear thermal expansion is 9.29 × 10−5/°C, indicating superior thermal stability. TGA analysis demonstrated a shift in decomposition temperature from 310 to 375 °C, confirming enhanced thermal stability. These results highlight the positive influence of ZnO nanofillers on both the mechanical and thermal properties of carbon fiber reinforced epoxy composites, making them more suitable for advanced structural applications.

Ti3C2Tx-UHMWPE Nanocomposites-Towards an Enhanced Wear-Resistance of Biomedical Implants.

There is an urgent need to enhance the mechanical and biotribological performance of polymeric materials utilized in biomedical devices such as load-bearing artificial joints, notably ultrahigh molecular weight polyethylene (UHMWPE). While two-dimensional (2D) materials like graphene, graphene oxide (GO), reduced GO, or hexagonal boron nitride (h-BN) have shown promise as reinforcement phases in polymer matrix composites (PMCs), the potential of MXenes, known for their chemical inertness, mechanical robustness, and wear-resistance, remains largely unexplored in biotribology. This study aims to address this gap by fabricating Ti3C2Tx-UHMWPE nanocomposites using compression molding. Primary objectives include enhancements in mechanical properties, biocompatibility, and biotribological performance, particularly in terms of friction and wear resistance in cobalt chromium alloy pin-on-UHMWPE disk experiments lubricated by artificial synovial fluid. Thereby, no substantial changes in the indentation hardness or the elastic modulus are observed, while the analysis of the resulting wettability and surface tension as well as indirect and direct invitro evaluation do not point towards cytotoxicity. Most importantly, Ti3C2Tx-reinforced PMCs substantially reduce friction and wear by up to 19% and 44%, respectively, which was attributed to the formation of an easy-to-shear transfer film.

Improved interfacial compatibility between unsaturated polyester resin and rice straw fibers after non-washing treatment with Ca(OH)2

The agricultural industry produces a substantial volume of rice straw (RS) annually, highlighting the importance of recycling RS for sustainable materials. However, the poor interfacial compatibility between RS and polymers often leads to drawbacks in their composites, such as water-swelling and limited tensile strength. Here, we propose a novel approach using Ca(OH)2 that offers several distinct advantages: enhancement of interfacial compatibility, elimination of the need for water washing, and formation of calcified hybrid particles on fiber surfaces by capturing CO2 from the atmosphere. The non-washing calcified rice straw (NCRS) fibers were used to fabricate composites with unsaturated polyester resin (UPR), resulting in NCRS/UPR composites exhibiting significant enhancements in water resistance and mechanical properties compared to RS/UPR composites. The NCRS/UPR composites achieved a water absorption rate below 25 %, thickness swelling rate below 10 %, and tensile strength of 19.9 MPa. This work comprehensively explored the mechanism underlying these achievements through experimental studies. Findings suggest that CaCO3 particles involving with released lignin act as an interfacial bridge between RS fiber surface and UPR, resulting in significantly improved properties. This approach demonstrates promising prospects as a simple and eco-friendly methodology for manufacturing RS-based composite materials.

Enhancing mechanical properties of carbonated steel slag through surfactant-assisted CaCO3 crystallization

This study investigates the enhancement of mechanical properties in carbonated steel slag through surfactant-assisted CaCO3 crystallization. Sodium dodecyl benzene sulfonate (SDBS) was employed at various concentrations (0.1–0.4 mol/L) and temperatures (20–60 °C) to modulate the carbonation process. Optimal performance was achieved with 0.2 mol/L SDBS at 40 °C, resulting in a maximum CO2 uptake of 8.51 % and a compressive strength of 62.89 MPa, 81.66 % higher than unmodified steel slag. Characterization techniques confirmed the formation of crystalline calcite, vaterite, and aragonite, contributing to improved microstructure and strength. SDBS micelles act as templates for CaCO3 nucleation and growth, with low concentrations facilitating carbonation and high concentrations inhibiting it. This research offers new insights into surfactant-assisted crystallization for enhancing carbonated steel slag properties, paving the way for high-performance, eco-friendly building materials from industrial waste.