Enhancement Of Mechanical Properties Research Articles

Micro milling of WE43 magnesium alloy cardiovascular stent and its mechanical property enhancement by ultrasonic vibration assisted micro deburring

WE43 magnesium alloy cardiovascular stents have broad application prospects in the treatment of vascular diseases. In this article, Mg alloy cardiovascular stent was manufactured by applying micro milling method, and ultrasonic vibration assisted micro deburring technique was adopted for its surface deburring after micro milling. Results show that burrs on the outer wall of the stents can be fully removed after 30 min, without damaging the dimensions and structure. The average surface roughness Ra can be decreased by 24.4 %. The maximum radial pressure can be decreased by 10.2 %, and the radial rebound rate of the stent can be decreased by 13.8 %, when compressed or expanded to the same diameter of the stent after deburring. The stability of the mechanical properties was also validated This study provides a promising method for preparing high-quality micro milling Mg alloy vascular stents with excellent mechanical properties.

Enhancement of Bioactivity, Mechanical and Degradation Properties of the Diopside by Incorporation of Ba2+ Ion via Sol–gel Combustion Route

Enhancement of Bioactivity, Mechanical and Degradation Properties of the Diopside by Incorporation of Ba2+ Ion via Sol–gel Combustion Route

Simultaneous enhancement in mechanical properties and flame retardancy of reed charcoal/polypropylene composites by graphene oxide interfacial modification

Biochar/polypropylene composites (BPCs) have great potential in automobiles and building materials due to their ease of processing and light weight. However, the inferior interfacial bonding strength between biochar and polypropylene (PP) and flammability of PP often result in the weak mechanical properties and poor flame retardancy of BPCs, which limit the practical applications of BPCs. Herein, graphene oxide (GO) is used as an active interfacial modifier to prepare graphene-reed charcoal/polypropylene (G-RC/PP) composites. Benefiting from the mechanical interlocking effect formed by GO, the G-RC/PP composites exhibit higher tensile and flexural strengths. When 1 % of GO was added (relative to mass of RC), the tensile and flexural strengths were 22.84 MPa and 50.8 MPa, respectively, which are 16 % and 22.7 % higher than pure PP. Additionally, the barrier-adsorption-dilution synergetic effects of GO enhance both the thermal stability and flame retardance of the composites. The total heat release rate of G-RC/PP composites is reduced by 71.6 % compared to RC/PP when GO was added at 1 %, resulting in a substantial reduction in fire hazards. This study offers a fresh perspective on the development of biochar/plastic composites with exceptional mechanical properties and high fire safety towards extensive applications as automotive parts and building structures.

Synergistic reinforcement mechanisms of Cu/graphite composites with MAX phase Ti2AlN and ZrO2-B4C ceramics: Enhancements in mechanical, thermal, and tribological properties

In braking materials field, MAX phase has been introduced into Cu-based composite materials to address issues such as inadequate wetting between ceramic particles and the metal matrix. This study focuses on preparing Ti2AlN-ZrO2-B4C reinforced Cu-based materials via the powder metallurgy method, and investigates the effects and mechanisms of different Ti2AlN/ZrO2 ratios on the mechanical, thermal, and tribological properties of these materials. The addition of an appropriate amount of Ti2AlN (3 wt%) can enhance the densification and mechanical properties of Cu-based materials, as the diffusion of Al atoms promotes the sintering process. Similarly, the diffusion of Al also improves the thermal conductivity at grain boundaries, resulting in samples with higher Ti2AlN content exhibiting superior thermal diffusivity. When the Ti2AlN content reached 7 wt%, the material exhibited optimal hardness (43.35 ± 1.05 HBW), moderate shear strength (19.84 ± 1.86 MPa), as well as excellent high initial braking speed friction coefficient and stability. The reinforcement primarily arises from the diffusion bonding between Ti2AlN and Cu, leading to the formation of Cu-Ti compounds at the interface, which facilitates Ti2AlN in providing frictional force during the friction process and promotes the formation of a friction film due to the “pinning effect”. Additionally, the layered structure of Ti2AlN and the subsequent formation of amorphous Al2O3 after oxidation contributed to the enhancement of friction stability.

Combustion and mechanical properties enhancement strategy based on stearic acid surface activated boron powders

Boric acid and other impurities on the surface of boron (B) particles can interact with hydroxyl-terminated polybutadiene (HTPB), weakening the mechanical properties and energy release efficiency of boron-based solid rocket propellants. SA@B composite particles were created by coating stearic acid (SA) on the surface of B particles through solvent evaporation-induced self-assembly. The study investigated the impact of SA coating on the combustion performance of B particles and the mechanical properties of HTPB matrix composites. The results showed that the SA coating enhanced the oxidation efficiency of B particles in air. The combustion heat of SA@B composite particles is 30.29 MJ/g, about 50% higher than that of B particles. During the combustion of SA@B composite particles, fewer molten solid particles surround the flame, which enhances the stability of the combustion process of the B particles. Furthermore, the SA coating effectively enhanced the dispersion of B particles in HTPB. At a stretching speed of 100 mm/min, the tensile strength of the SA@B/HTPB composite materials is higher than that of the B/HTPB composite materials. Moreover, when the mass loading of the SA@B composite particles reaches 50 wt%, the tensile strength of SA@B/HTPB composite materials is 2.46 MPa. Activating the surface of boron particles with SA can significantly improve their compatibility with HTPB, which is crucial for the stable storage of boron-based solid rocket propellants.

Investigating the Corrosion Inhibition Performance of a Novel Coconut Oil-Based Poly(urethane-urea) Hybrid Coating on Carbon Steel in 3.5% NaCl Solution

Polyurethane has been used for years as an anti-corrosion coating due to its intrinsic hydrophobic properties. However, its hydrophobicity is not enough to inhibit the permeation of corrosive agents; thus, incorporating it with polyurea would further enhance its hydrophobic properties. In this study, coconut oil, a saturated, low molecular weight vegetable oil, was employed as an eco-friendly precursor for synthesizing a novel poly(urethane-urea)- based hybrid coating. The synthesis process involved the utilization of a coconut oil-based polyol blend, triethanolamine (TEA) as an amine source, and hexamethylene diisocyanate (HDI). The resulting hybrid coating on carbon steel demonstrated remarkable anticorrosion performance in a 3.5 wt. % NaCl solution, owing to the intrinsic hydrophobic characteristics of coconut oil and polyurea. Significant corrosion rate reduction was observed with increasing amine content, accompanied by an enhancement in mechanical properties. Notably, an amine loading of 4% consistently exhibited superior corrosion resistance and mechanical performance in the hybrid coating. Chemical structural analysis revealed a hydrogen-bonding network in polyurea coatings, reducing porosity, enhancing barrier properties, and improving mechanical characteristics, highlighting its potential for sustainable corrosion protection.

The effect of silane‐modified carbon black and nano‐silica, individually and in combination, on the performance of ethylene–propylene–diene monomer rubber

AbstractThis study assesses the effectiveness of a specially developed surface‐modified carbon black, both on its own and in combination with nano‐silica, as a hybrid filler for ethylene–propylene–diene monomer (EPDM) rubber compounds. The modification process, which included treatment with a silane coupling agent, resulted in enhanced curing characteristics. The ∆Torque values for compounds incorporating the modified carbon black exceeded those of other formulations by 25.85%. Scanning electron microscopy (SEM) analysis demonstrated improved filler dispersion and better compatibility between rubber and filler due to the surface modification. The silane‐modified carbon black showed considerable enhancements in mechanical properties, particularly in tear resistance, with increases in tensile and tear strength of 22.46% and 34.86%, respectively, following surface treatment. Dynamic mechanical analysis (DMA) indicated the influence of both surface modification and filler type, revealing that the combination of modified carbon black and nano‐silica achieved a reduction in rolling resistance of 20.41% and enhanced ice and wet grip performance by 7.95%. Additionally, modified carbon black displayed varying effects on the glass transition temperature. Thermal gravimetric analysis (TGA) confirmed that the thermal stability of the compounds was consistent, while solvent resistance improved with surface modification, as shown by swelling ratios. Thermodynamic analysis indicated that the surface modification of carbon black positively influences the elasticity and chain mobility of the rubber compounds studied. In conclusion, the careful selection and optimization of filler materials and their modifications are essential for customizing the properties of rubber compounds to satisfy specific performance criteria and applications.Highlights Promising EPDM compounds were prepared with Silane‐Modified CB and Nano‐Silica. Silane‐modified CB effectively improved the curing properties of the EPDM compound. The ΔTorque and cross‐link density of modified CB/EPDM show the highest value. Modified CB/Nano‐Silica/EPDM exhibited significant improvement in tear strength. Modified CB/Nano‐silica/EPDM have lower rolling resistance and higher wet grip.

Enhancement of High-Temperature Mechanical Properties in Al-Si-Cu-Ni-Mg Alloy by Micro-nano TiC Particle Complex Clusters

Enhancement of High-Temperature Mechanical Properties in Al-Si-Cu-Ni-Mg Alloy by Micro-nano TiC Particle Complex Clusters

Effect of cold-rolling and annealing temperature on microstructure, texture evolution and mechanical properties of FeCoCrNiMn high-entropy alloy

This study investigates the effects of cold rolling and annealing on the microstructure, texture, and mechanical properties of FeCoCrNiMn high-entropy alloys. Utilizing vacuum induction melting, the alloy was initially cast into ingots and hot-rolled into plates, which were subsequently cold-rolled to various thicknesses and annealed at different temperatures. Microstructural analyses were conducted using X-ray diffraction and electron backscatter diffraction techniques, revealing a persistent face-centered cubic structure across all conditions. The texture evolution demonstrated a shift from Copper and S components to dominant Goss and Brass components as cold rolling intensified, suggesting the formation of Brass-type texture in FeCoCrNiMn at high deformation. Mechanical testing showed that the alloy's yield and tensile strengths significantly increased with cold rolling, reaching optimum values at ∼66 % reduction. Annealing at 750 °C enhanced both strength and ductility, primarily through grain refinement and the formation of Σ3 annealing twin boundaries, which dominated the microstructure of recrystallized grains. The study confirms that the low stacking fault energy of the alloy facilitates the activation of twinning and transformation-induced plasticity mechanisms, crucial for the observed enhancements in mechanical properties.

Heat treatment of FDM and SLS delicate additive manufacturing products: mechanical properties enhancement and dimensional accuracy

Heat treatment of FDM and SLS delicate additive manufacturing products: mechanical properties enhancement and dimensional accuracy

Molecular dynamics simulations of the micro mechanism of functionalized SiO2 nanoparticles and carbon nanotubes modified epoxy resin adhesives

AbstractThe bonding interface of carbon‐fiber‐reinforced polymer (CFRP)‐reinforced steel structure is a weak part, and nanomaterial‐modified adhesives are expected to improve its comprehensive performance. This paper investigates the micro‐modification mechanisms of nanomaterials on epoxy resin adhesives using molecular dynamics simulation method. It explores how the functionalized nano SiO2 and carbon nanotubes affects the thermal and mechanical properties of the epoxy resin adhesive. The models established using Materials Studio software include the pure epoxy resin adhesive model (EP) with varying degrees of crosslinking, the functionalized nano‐SiO2‐modified epoxy resin adhesive model (EP + SiO2/OH), the single‐walled carbon nanotube‐modified epoxy resin adhesive model (EP + SWNT), and the synergistic enhancements model of the epoxy resin adhesive with nano‐SiO2 and carbon nanotubes (EP + SWNT + SiO2/OH). Based on the aforementioned models, the Forcite module is used to calculate the free volume, glass transition temperature and mechanical properties of the adhesive. The results show that the degree of crosslinking effects significantly the mechanical performance of epoxy resin adhesive. A high degree of crosslinking restricts the movement of the molecular chain, enhancing the strength of the epoxy resin adhesive. Furthermore, the trend of the mechanical and thermal properties of the four models remains constant with the rise of temperature, and the properties decrease most significantly in the range of the glass transition temperature. Moreover, the epoxy resin adhesive doped with nanomaterials exhibits varying degrees of enhancement in mechanical and thermal properties. The epoxy resin adhesive reinforced with functionalized nano‐SiO2 and carbon nanotubes exhibits better properties compared to those with a single nanomaterial.Highlights The micro‐modification mechanism is revealed for nanomaterial modified epoxy resin adhesive. The degree of crosslinking effects significantly the mechanical performance of epoxy resin adhesive. The epoxy resin adhesive doped with nanomaterials exhibits varying degrees of enhancement in mechanical and thermal properties.

Research on the microstructure and mechanical properties of functional gradient materials of TC4/TC11 titanium alloys for wire arc additive manufacturing with different transitional forms

Functional gradient materials (FGMs) have garnered increasing interest for their potential in material and structural design. Additive manufacturing, as a kind of free manufacturing and near-net shaping technology with in-situ controllability of materials, is the dominant technology for fabricating FGMs. While numerous studies have been conducted on titanium alloy FGMs, there is still a lack of research on the structure and properties of the material with the number of transitional layers. This study employs double-wire arc additive manufacturing to fabricate FGMs composed of TC4 and TC11 alloys. The study examines the utilization of direct and continuous transition forms in conjunction with stress relieving and solution aging heat treatment processes. The composition, grain morphology, microstructure, and mechanical properties of FGMs are analyzed. Results indicate that in samples employing direct transition, higher heat treatment temperatures and durations lead to a more uniform composition and microstructure. Additionally, the interface morphology becomes increasingly indistinct, and transversal elongation at the interface is enhanced by the strain compensation of the two materials. In continuous transitional samples, an increase in the number of transitional layers results in a more uniform microstructure near the interface, leading to a reduction in interface morphology and an enhancement of mechanical properties. The fracture position tends to shift closer to the TC4 side, with both process forms exhibiting ductile fractures. The plasticity of the TC4 part is superior, and the ductile fracture morphology is more pronounced. This study offers a valuable experimental foundation for investigating the direct and continuous transition of titanium alloy FGMs.

Tasar silk fiber waste reinforced polylactic acid composite: Physical, mechanical, and sliding wear characterization

Incorporating natural industrial waste as a reinforcement for the development of sustainable composite is now being extensively practiced to eliminate harmful synthetic fiber. This study exhaustively evaluated the potential of tasar silk fiber waste (TSFW) as a reinforcing agent in a polylactic acid (PLA) matrix to optimize the physical, mechanical, and wear properties. Therefore, PLA-based biocomposites with varying TSFW proportions (0, 2, 4, 6, 8, and 10 by weight) are manufactured and then evaluated for physical (density, voids, water absorption), mechanical (tensile, flexural, impact, and hardness), and sliding wear properties. Results suggested that water uptake of PLA composites increases with the addition of TSFW and becomes saturated after nine days of immersion. The TSFW reinforcement at 8 wt% in PLA yields 32 % and 22 % improvement in tensile strength (66.2 MPa) and flexural strength (103.2 MPa), respectively. A remarkable improvement was observed in the impact strength at similar reinforcement (8 wt%) of TSFW with the observed value of 27.90 kJ/m2. A continuous increase in hardness was obtained by including TSFW in PLA, with the highest value of 86 Shore D recorded for 10 wt% TSFW added biocomposite. The specific wear rate of all samples increased, but the incorporation of TSFW significantly reduced the same. Microscopic examination suggests that microploughing, microcutting and groove formations were the main mechanism of material removal. After examining the results, it is recommended that TSFW be used in bidirectional mat form for further enhancement of mechanical properties and improved bonding between fiber and matrix.

Enhancement of Mechanical Properties of Zein-Based Nanofibers by Incorporation of Millet Gliadin.

In this work, a novel reinforcing filler, millet gliadin (MG), was used for the improvement of the mechanical properties of zein nanofibers. The structural and physicochemical properties of MG were compared with those of zein, and the influence of MG on the morphology, physical properties, and molecular structure of zein nanofibers was investigated. The results indicated that MG has an obviously smaller weight-average molecular weight (7623) in comparison to zein (13,330). Transmission electron microscopy showed that zein molecules more easily form aggregates with larger diameters than MG molecules in acetic acid. At a concentration of 30% (w/v), MG exhibited a significantly higher viscosity (0.66 ± 0.03 Pa·s) than zein (0.32 ± 0.01 Pa·s), indicating the stronger interactions of MG molecules. With the incorporation of MG, the tensile strength was significantly increased to 49.32 MPa (ZM-1/2), which is 2.08 times and 4.45 times higher than that of pure zein nanofibers (ZM-1/0) and MG nanofibers (ZM-0/1-1), respectively. Moreover, zein/MG composite nanofibers exhibited improved water stability. Fourier transform infrared spectra showed evidence of the hydrogen bonding interaction between zein and MG. Therefore, MG is a good candidate for use as a natural reinforcing filler in electrospun nanofibers made of biopolymers.

Fabrication of Flexible Wearable Mechanosensors Utilizing Piezoelectric Hydrogels Mechanically Enhanced by Dipole-Dipole Interactions.

Conductive hydrogels have been increasingly employed to construct wearable mechanosensors due to their excellent mechanical flexibility close to that of soft tissues. In this work, piezoelectric hydrogels are prepared through free radical copolymerization of acrylamide (AM) and acrylonitrile (AN) and further utilized in assembling flexible wearable mechanosensors. Introduction of the polyacrylonitrile (PAN) component in the copolymers endows the hydrogels with excellent piezoelectric properties. Meanwhile, significant enhancement of mechanical properties has been accessed by forming dipole-dipole interactions, which results in a tensile strength of 0.51 MPa. Flexible wearable mechanosensors are fabricated by utilizing piezoelectric hydrogels as key signal converting materials. Self-powered piezoelectric pressure sensors are assembled with a sensitivity (S) of 0.2 V kPa-1. Additionally, resistive strain sensors (gauge factor (GF): 0.84, strain range: 0-250%) and capacitive pressure sensors (S: 0.23 kPa-1, pressure range: 0-8 kPa) are fabricated by utilizing such hydrogels. These flexible wearable mechanosensors can monitor diverse body movements such as joint bending, walking, running, and stair climbing. This work is anticipated to offer promising soft materials for efficient mechanical-to-electrical signal conversion and provides new insights into the development of various wearable mechanosensors.

Direct tensile failures of concrete with various moisture contents and sizes at low temperatures via mesoscale simulations with ice explicit modelling

The enhancement of mechanical properties of concrete meso-components and the interaction caused by non-uniform deformation as well as phase change can cause significant changes in the macro-mechanical performances of concrete at low temperatures. Based on the action mechanism of the above low-temperature effect, this paper established a thermal-mechanical sequential coupled simulation method with explicit modelling of pore ice at the mesoscale level to quantitatively investigate the direct tensile failures and the corresponding size effect of concrete with four structural sizes (D75, D150, D225 and D300) and three moisture contents (2.0 %, 4.0 % and 6.0 %) at different temperatures (20, −30, −60 and −90°C), in term of failure mode, deformation curve, peak strength and residual strength. The numerical results show that the direct tensile peak strength performs an obvious low-temperature enhancement effect due to the more damaged aggregates and more areas being in a state of multi-axial stress caused by low-temperature non-uniform stress field. However, with the decreasing temperature, the residual strength shows a decrease trend and the trend slows down with the increasing moisture content. Besides, as the temperature drops from 20°C to −90°C, both the size effects on direct tensile peak strength and residual strength are strengthened (with the increase approaches nearly 200 % for peak strength while 33 % for residual strength). Finally, a modified size effect theoretical model was developed considering the quantitative coupling effects of low temperature and moisture content. The present research results can provide a reference for the performance evaluation and safe design of large-sized concrete exposed to low-temperature environments.

The impact of nanofiller composition and nature on the enhancement of mechanical and rheological properties of poly(lactic acid) (PLA) nanobiocomposite films is achieved by regulating the spacing of organic fillers and PLA crystallinity

The impact of nanofiller composition and nature on the enhancement of mechanical and rheological properties of poly(lactic acid) (PLA) nanobiocomposite films is achieved by regulating the spacing of organic fillers and PLA crystallinity

Graphene Oxide-Silica Green Hybrid Nanocomposites: Fabrication via Latex Mixing and Mechanical Properties Evaluation

ABSTRACT This study investigates the incorporation of sustainable self-assembled graphene oxide-nano silica (GO/NS) hybrid nanoparticles into the natural rubber latex matrix via latex mixing. The primary objective is to assess the synergistic impact of these nanofillers on the mechanical properties of natural rubber latex using both static and dynamic mechanical analysis. Results reveal significant enhancements in mechanical properties, with NRL GO/NS 2 exhibiting a remarkable 188% increase in tensile strength and NRL GO/NS 3 showing a substantial 107% increase. Furthermore, NRL GO/NS 3 demonstrates a 30% reduction in rolling resistance and a remarkable 200% improvement in wet grip, while NRL GO/NS 2 exhibits an 88% increase in wet grip and a 43% decrease in rolling resistance, suggesting potential fuel efficiency benefits. These advancements hold promise for various applications such as automotive tire manufacturing, biomedical devices, and the production of elastomeric goods.

In-situ formed silicon oxycarbide nanowires into porous SiC(rGO) PDCs enable balanced enhancement of robustness and thermal management

With ongoing development of rocket combustion and hypersonic vehicles, urgent needs are created on thermal structures, protection and thermal insulating materials, particularly balanced enhancement of mechanical and antioxidant properties. Herein, we propose a design strategy to construct continuous in-situ formed SiOC nanowires (SiOCnws)-toughened self-healing SiOx coatings into porous SiC(rGO) PDCs. The key production technique is re-pyrolyzing coassembled flexible precursors/SiC(rGO)p/graphite blends, followed by decarbonization and silica sol impregnation-sintering (SIS) process. Well-distributed hierarchical pores are built to heighten thermal insulation properties by the integrated decarburization of graphite coupled with free carbon. High-yield SiOCnws, with high surface activity, are first cultivated via graphite-assisted vapor-solid (VS) mechanism without transition metal catalysts. They interconnect to form intricate 3D meshwork by graphite-assisted melt-spinning and have good compatibility with ceramic matrix and SiOx coatings by carbothermal reaction. Hierarchically porous SiOCnws/SiC(rGO)40% PDCs after once SIS exhibit favorable thermal conductivity of 0.27 W‧m−1‧K−1 and exceptional high robustness (compressive strength: 39.02 MPa, hardness: 10.27 GPa). Such composites display low reflection loss of −48.14 dB at 11.22 GHz and even good structural stability at about 1300 °C as burned by a butane blowtorch for 3600 s, shedding light on competitive components for uses in thermal protection fields.

Enhancement of Mechanical Properties of NiCo Alloy Induced by Inhomogeneous Gradient of Solute Element Segregation

Inhomogeneous gradient nanocrystals have better mechanical properties than uniform gradient nanocrystals. The segregation of solute elements in inhomogeneous gradient nanocrystals is expected to induce the re‐enhancement of mechanical properties of alloys. Herein, solute element segregation structures of inhomogeneous gradient structure nanocrystalline NiCo alloy are established, simulating tensile deformation via molecular dynamics. The results show that the segregation of solute elements in the inhomogeneous gradient structure of nanocrystals can improve the mechanical properties of the alloy, especially the structure of the intragranular segregation. The intragranular segregation of solute elements induces the decrease of grain boundary energy and greatly enhances the stability of grain boundaries. In addition, the segregation of solute elements within grains can hinder the dislocation movement to a certain extent, and the hindering effect on dislocation movement of stable grain boundaries induced by intragranular segregation of solute elements further enhances the mechanical properties of nanocrystalline alloys. This strategy of combining heterogeneous gradient structure and solute element segregation structure provides a positive and interesting perspective for the design of advanced alloys with excellent properties.