Graphene Reinforcement Research Articles

Effect of Graphene Reinforcements on the Natural Frequencies of Metal Foams Sandwich Spherical Panels Situated on Kerr Elastic Foundation Considering Moisture Changes

The existing study examines the moisture-dependent vibrational behavior of a metal foam spherical panel that is positioned between two composite layers reinforced with graphene platelets (GPL). The Kerr foundation, a three-parameter elastic foundation, supports the model. Based on specified functionalities, the pores’ arrangement and the GPL dispersion throughout the core and face sheets, respectively, are taken into consideration. The Halpin–Tsai and extended rule of mixture micromechanical models are utilized to ascertain the face sheets’ effective hygromechanical property values. After the motion equations are determined, the frequencies are extracted using the analytical technique, which is particularly effective for shells with simply supported edges. The impacts of various influences on the natural frequencies are considered and addressed over the course of the inquiry. It is shown that natural frequencies drop with increasing porosity coefficient. Furthermore, a small amount of GPL is shown to have a strong reinforcing effect on the stiffness of the structure, hence enhancing natural frequencies. The outcomes of this investigation can be beneficial to a variety of industries such as aerospace, automotive, marine, and civil engineering, where spherical shells are commonly employed. Furthermore, the outcomes might function as a standard for subsequent research. These results not only advance the understanding of moisture effects on composite structures but also provide a foundation for future research aimed at optimizing material properties for specific applications. Additionally, this study offers practical insights for the design and manufacturing of more resilient and efficient spherical components in real-life engineering scenarios.

Investigation of aluminum-based mono and hybrid surface composites by incorporating SiC and graphene reinforcements using friction stir processing

The present investigation focuses on the synthesis of mono (AA5052/SiC and AA5052/graphene) and hybrid (AA5052/SiC/graphene) surface composites using friction stir processing (FSP). This work examines the synergistic effect of SiC and graphene on the fabricated surface composites. Macro/microstructure, microhardness, and wear test analysis were done on these samples, and the results were compared with the base material AA5052-H32. The microstructure analysis showed that the distribution of reinforcement particles in the aluminum matrix is made more uniform by adding hard SiC with graphene nanoparticles, which can reduce the occurrence of particle clustering and agglomeration. As a result, the smallest grain size of 11.2 µm and the highest microhardness obtained was 84.1 HV obtained in hybrid surface composites. Consequently, the hybrid surface composites obtained more improved wear properties than mono surface composites. Thus, the hybrid surface composites achieved the lowest average friction coefficient of 0.304.

Forced vibration analysis of sandwich beam reinforced with graphene in piezoelectric medium on elastic substrate

In this study, using an analytical and precise solution, the dynamic transverse deflection of a five-layer beam with Prussian core with graphene platelet reinforced composite (GPLRC) under a moving harmonic load on a Pasternak elastic substrate is analyzed. First, the properties of the porous core materials and the piezoelectric layer and surface, which were graphene platelet reinforcements (GPLRs), were defined. The constitutive relations were extended using the Bonilla’s higher-order theory and Hamilton’s principle, relationships were extracted. Finally, using the Laplace method and analytical solution. A parametric analysis is provided to investigate impact of temperature distribution, porosity coefficient, thickness ratio, spring constant, voltage and excitation frequency on the responses.

Mechanical and microstructural characteristics of Al-Li2099-graphene MMCs for aerospace applications

ABSTRACT Aluminium-Lithium (Al-Li) alloys are known for its properties that are superior to conventional ones. The inclusion of graphene reinforcements to the metal matrix improved strength, stiffness, density reduction, tensile properties, wear, creep, and fatigue resistance. This study examined the combined result of graphene nanoparticles (GNP) and the Al-Li2099 alloy with an ultrasonic-aided stir-casting process. The nano-particulate metal matrix composites with various weight percentages (wt. %) of GNP were fabricated and investigated for physical, mechanical, and microstructural properties. The nanocomposites’ mechanical properties were examined in detail, and significant improvements in hardness, tensile, and compressive strength were observed with higher wt. % of GNP. Theoretical and empirical densities were measured, revealing that the nanocomposite’s densities decrease with the increase in wt. % of nano-reinforcements. Material characterisation of the composites was carried out using XRD, EDAX, SEM, and Fourier-Transformation Infrared Spectroscopy (FTIR). SEM and EDAX confirmed the presence of GNP particulates in the matrix microstructure and elemental composition. The XRD results confirmed the presence of GNP particulates in the Aluminium Alloy (AA) 2099 and the composite, and no other intermetallic elements were detected. The results demonstrated that the GNP addition to the AA2099 significantly enhanced the mechanical and microstructural characteristics of the nanocomposite.

Graphene, graphene oxide or modified graphene in polyaniline based nanocomposites—features and technical highlights

Polyaniline is a remarkable conjugated polymer having valuable structural and physical characteristics. Nevertheless, polyaniline has poor solubility and structural durability which had limited its practical utilization. Consequently, polyaniline has been reinforced with carbonaceous and inorganic nanoparticles to enhance its processability and physical properties, such as electrical/thermal conductivity and thermal/mechanical stability. Accordingly, polyaniline has been applied as a valuable matrix material to form nanocomposites with graphene which is a one atom thick nanosheet of hexagonally arranged carbon atoms. Subsequently, graphene as well as modified graphene forms have been utilized as important nanoadditives for the polyaniline matrix. This state-of-the-art review article has been designed to investigate the fabrication, characteristics, and applications of the polyaniline and graphene/modified graphene based nanomaterials. Potential enhancements in the physical characteristics of the pristine polyaniline upon graphene reinforcement seemed to be reliant upon the matrix-nanofiller interactions, interface formation, and synergetic effects between polyaniline-graphene. Subsequently, practical aspects of the polyaniline/graphene nanocomposites have been discussed regarding their applications in the fields of solar cells, supercapacitors, and sensors. According to the literature analysis, dye sensitized solar cell based on polyaniline/graphene and polyaniline/graphene oxide exhibited superior power conversion efficiencies ∼2.0-7.6 % and open circuit voltage ∼500-800 mV. Supercapacitor electrodes based on polyaniline/graphene oxide and polyaniline/reduced graphene oxide showed significantly high values of specific capacitance and capacitance retention of ∼1100-1900 Fg−1 and ∼80-98 %, respectively, during >5000-6000 cycles. Besides, the polyaniline/graphene oxide depicted superior sensitivity and response time for gas sensors (∼20 % and 50 s, respectively) and humidity sensors (>90 % and 4-7 s, respectively) and low detection limits for biosensors.

Effects of graphene reinforcement on morphology, thermophysical, and mechanical properties of polyvinyl alcohol and polyacrylamide in condensed phases

The subtle interplay of noncovalent interaction in enhancing the compatibility between the graphene-based material and the oligomers of polyvinyl alcohol (PVA) and polyacrylamide (PAM) in the solvent phase is unraveled within the framework of all-atom classical force field-based molecular dynamics (MD) simulations. The decomposition of binding free energy analysis demonstrates that the interaction between polymer segments and graphene (G)-surface crucially emanates from the van der Waals (vdW) interactions, while the adsorption of polymer chains on the graphene oxide (GO)-surface is influenced by vdW and electrostatic interactions. The influence of diverse factors including the strain rate, the size of the nanofiller, the number of oligomers, and the thermal quenching rate on controlling the morphology, mechanical, and thermophysical properties of the graphene-reinforced polymer nanocomposites are further explored. The uniaxial deformation simulations of the graphene-reinforced PVA and PAM matrices show that the interfacial mechanical strength is escalated for the G-PVA nanocomposite. The inclusion of graphene nanofiller reduces the polymer chain mobility and increases the intermolecular interaction, which in turn enhances the toughness of the graphene-polymer composites. Increasing the strain rate raises the yield strength and modulus, making the composites appear stronger and stiffer. As evidenced by the predicted glass transition temperature, the thermal stability of the PVA and PAM matrices is significantly improved by the graphene reinforcement.

Electro-Mechanical Behavior of Copper-Based Electrical Motor Brushes

This study was mainly performed in order to examine the properties of electric motor brushes (EMB). EMBs are electrically conductive and work under wear conditions due to direct contact with the moving part (rotor) of electric motors. In accordance with the scope of the study, EMB characteristics were investigated in two different groups and reproduced with a new technique at the end of this phase. New EMBs were produced via varying proportions of copper matrix, graphene, and silicon carbide reinforcements. The composite-alloy powder elements were carefully squeezed by a cold and single-axis hydraulic press under a pressure of 500 MPa (±5 MPa) following 8 hours of mechanical alloying (MA). The molded composite product (sample) was sintered at 900° C for 1 hour in a reducing gas atmosphere. 100 kPa spring pressure was tested on each sample thrice with 8, 16, 24, and 32 m/s rotational speeds and densities of 4, 8, 12, and 16 A/cm2. Following this process, the electrical conductivity, porosity, hardness, wear loss, surface roughness, and temperature changes were investigated for each sample. It was determined that the electrical conductivity decreased with increasing reinforcement ratio and, in terms of electrical conductivity, affected the brushes’ properties negatively.

Impact of annealing on the characteristics of 3D-printed graphene-reinforced PLA composite

Manufacturing through additive techniques, especially utilizing the fused filament fabrication (FFF) method, is a transformative technology revolutionizing design and manufacturing. FFF builds parts layer by layer using thermoplastic polymer and polymer composite filaments. However, weak interlayer connections often lead to low interlaminar resistance in printed structures. Recent studies suggest that post-deposition heat treatments can mitigate this issue by reducing internal thermal stresses and enhancing layer adhesion, thereby improving part properties. This research delves into the impact of annealing heat treatment on a composite of Polylactic Acid (PLA) reinforced with graphene. The annealing process was conducted at temperatures of 90, 100, and 120 °C for durations of 60, 120, and 240 min. The annealing response of the graphene-reinforced PLA composite is compared to that of natural PLA for reference, analyzing its effects on electrical, thermal, chemical, and mechanical properties. Chemical characterization was performed using X-ray diffraction (XRD), Raman spectroscopy, and Fourier-transform infrared spectroscopy (FTIR). Thermal properties were analyzed via thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Electrical properties were assessed by measuring resistance, resistivity, and conductivity. Mechanical properties were evaluated through tensile, flexural, notch sensitivity, impact tests, and hardness measurements. The results demonstrated that annealing of graphene-reinforced PLA and natural PLA did not alter their functional groups but increased their crystallinity. This treatment improved thermal stability, electrical conductivity, and mechanical properties, including tensile strength, flexural strength, and Shore D hardness. However, it reduced impact and notch sensitivity resistances. The increased crystallinity had a greater beneficial impact on some properties than the graphene reinforcement. These findings have potential applications in the automotive, aerospace, electronics, and medical sectors, given the increasing use of PLA in these industries.

(Alumina and graphene)/ PLA nanocomposites manufactured by digital light processing 3D printer

In this study, the variant effects of alumina and graphene reinforcing nanoparticle percentages on the tensile and wear properties of the nanocomposites, produced using digital light processing (DLP), were determined by employing SEM images of fracture and worn surfaces to introduce a hybrid (alumina + graphene)/PLA nanocomposite with desirable wear and mechanical properties. With the addition of alumina up to 2 wt%, the tensile strength was initially decreased exhibiting a rapid brittle fracture over the flat fracture surface. However, with a continued increase in the amount of reinforcing particles, the tensile strength eventually increased by 16% compared to the pure resin sample at 8 wt% of alumina while changing the fracture mode with plenty of cleavages accompanied by crack deflections. The specific wear rate in the 8 wt% alumina sample decreased by almost 62% compared to the pure resin sample. Graphene caused a significant drop in tensile strength due to the generation of cavities and porosities around the graphene agglomerates, but it greatly improved the wear properties, with the specific wear rate decreasing by almost 77% at just 1 wt%. Then hybrid nanocomposites of alumina and graphene reinforcements were produced with the aim of optimal tensile and wear properties. The 0.5% graphene +3.5% alumina improved the wear resistance and provided moderate tensile properties; however, the 1% graphene +3% alumina could not increase the wear resistance due to the weakening of graphene plates sticking to the polymer substrate.

Experimental Investigation into the Preparation Process of Graphene-Reinforced Aluminum Matrix Composites by Friction Stirring Processing.

Graphene has been considered an ideal reinforcement in aluminum alloys with its high Young's modulus and fracture strength, which greatly expands the application range of aluminum alloys. However, the dispersion of graphene and the interfacial reaction between graphene and the aluminum matrix limit its application due to elevated temperature. Friction stirring processing (FSP) is regarded as a promising technique to prepare metal matrix composites at lower temperatures. In this paper, FSP was used to prepare graphene-nanoplates-reinforced aluminum composites (GNPs/Al). The corresponding effects of the process parameters and graphene content on GNPs/Al were thoroughly studied. The results showed that plastic strain, heat input, and graphene content were the key influencing factors. Large degrees of plastic strain can enhance the dispersion of graphene by increasing the number of stirring passes and the ratio of stirring to welding velocity, thereby improving the strength of GNPs/Al. Low heat input restricts the plastic flow of graphene in the matrix, whereas excessive heat input can promote interfacial reactions and lead to the formation of a more brittle phase, Al4C3. This is primarily associated with the stirring velocity and welding velocity. High graphene content levels can improve the material strength by refining the grain size, improving the load transfer ability, and acting as a precipitate to prevent dislocation movement. These findings make a contribution to the development of advanced aluminum alloys with graphene reinforcement, offering broader application potential in industries.

Characterization, impact and wear properties of treated and as-received graphene nanosheets reinforcement in epoxy resin composites

PurposeThis study aims to explore the enhancement of mechanical properties in epoxy resin composites through the incorporation of graphene nanoparticles, focusing on their impact and wear resistance. It investigates the role of graphene, both treated and untreated, as a reinforcing agent in composites, highlighting the significance of nanoparticle dispersion and surfactant treatment in optimizing mechanical performance.Design/methodology/approachEmploying a novel dispersion technique using a drawing brush, this research contrasts with traditional methods by examining the effects of graphene nanoparticle concentrations treated with surfactants – Polyvinylpyrrolidone (PVP) and Sulphonated Naphthalene Formaldehyde (SNF) – on the mechanical properties of epoxy resin composites. The methodology includes conducting a series of impact and wear tests to assess the influence of graphene reinforcement on the composites' performance.FindingsThe findings reveal a marked enhancement in the composites impact resistance and energy absorption capabilities, which escalate with an increase in graphene content. Additionally, the study demonstrates a significant improvement in wear resistance, attributed to the superior mechanical properties, robust interface adhesion and effective dispersion of graphene. The use of surfactants for graphene treatment is identified as a crucial factor in these advancements, offering profound insights into the development of advanced composite materials for diverse industrial uses.Originality/valueThis study introduces a unique dispersion technique for graphene in epoxy composites, setting it apart from conventional methods. By focusing on the critical role of surfactant treatment in enhancing the mechanical properties of graphene-reinforced composites, it provides a novel insight into the optimization of impact and wear resistance.

Influence of nano graphene filler on hardness, impact strength and density of glass epoxy composites

AbstractThis study investigates the effects of graphene reinforcement on the hardness and impact strength of glass epoxy composites. Four different materials were examined: pure epoxy (EP), glass epoxy (GE), glass epoxy with 1 wt.% graphene (GE1), and glass epoxy with 2 wt.% graphene (GE2). The results show that the incorporation of graphene significantly enhances the hardness of the composites. Pure epoxy (EP) exhibited a Shore D hardness of 60 and an impact strength of 0.09 J/m2. The glass epoxy (GE) showed a reduction in hardness to 56 but an increased impact strength of 0.15 J/m2 due to the inclusion of 33 wt.% glass fiber. Further addition of graphene in GE1 and GE2 led to notable improvements in hardness, reaching 68 and 74 Shore D, respectively. However, the impact strength displayed a decrease with the inclusion of graphene, with GE1 and GE2 showing values of 0.13 and 0.11 J/m2, respectively. When transitioning from pure epoxy (EP) to glass epoxy (GE), there is a 6.67% decrease in hardness, while the impact strength increases by 66.67%. Introducing 1 wt.% of graphene to the glass epoxy (GE1) results in a 21.43% increase in hardness but a 13.33% decrease in impact strength. Further adding 2 wt.% of graphene (GE2) leads to an additional 8.82% increase in hardness, though the impact strength decreases by 15.38%. X‐ray diffraction (XRD) analysis has revealed nano graphene presence and distribution, while fractography has revealed its effectiveness in enhancing interfacial adhesion and toughening mechanisms. Furthermore, XRD identifies potential changes in crystallinity or phase composition induced by nano graphene incorporation, further elucidating the composite's structure and properties. The study highlights the novel and significant trade‐offs encountered in optimizing the mechanical properties of epoxy‐based composites by incorporating graphene and glass fiber.

Effect of the lateral area of graphene nanosheets on the strengthening mechanism in FGH96 superalloy composites

To improve the strengthening effect of graphene reinforcement in nickel-based superalloys, introducing graphene nanosheets (GNSs) with multiple lateral areas into the GNS/metal system is a promised strategy to take full advantage of the superior properties of graphene reinforcement. In this work, the impact of the GNS lateral area on the strengthening effect of FGH96 nickel-based superalloy composites (DLA-GNS/FGH96) was investigated for the first time. Microstructural and tensile tests revealed the uniform distribution of the GNSs in the DLA-GNS/FGH96 metal matrix with lateral areas ranging from 0.06 ± 0.02 to 225.2 ± 20.3 μm2. The GNSs exhibited a well-balanced mechanical property on the elongation and yield strength of the DLA-GNS/FGH96 composites. Investigation of the fracture morphology and mechanism indicated that there existed a transition of the strengthening mechanism (between the strengthening mechanism of Orowan and the strengthening mechanism of load-transfer) for the GNSs, which was closely associated with the lateral area of the GNSs. This finding put forward new ideas to better comprehend the strengthening mechanisms of GNS-reinforced metal-matrix composites.

A new investigation on graphene-reinforced 304L nanocomposite made by additive manufacturing process: Microstructure and tribology study

In this study, selective laser melting (SLM), as an additive manufacturing method, was applied to produce graphene/304L nanocomposites with various graphene particle sizes and contents. The effect of the graphene particle size (1 μm and 50 nm) and volume fraction on the microstructure behaviors, constitutional phases, mechanical performance, and wear characteristics of the SLM-processed nanocomposite specimens was studied. It was concluded that the reinforcing particle content and size play a remarkable impact on the densification features and the densification level improvs when the fine starting reinforcing particles are used, due to the development of the reinforcement–matrix wettability. In addition, the microstructure refinement and increased hardness values occurred in the SLM-processed nanocomposite system with the addition of reinforcing particles (both sizes). The wear examination indicated that the coefficient of friction (COF), wear rate, and mass loss decreased due to the reinforcement prominent effect, namely grain refinement and grain-boundary strengthening. According to surface topography analysis, the depth of the groove in the processed sample made by fine graphene reinforcement is lower than the other sample.

Effects of Graphene Reinforcement on Static Bending, Free Vibration, and Torsion of Wind Turbine Blades.

Renewable energy markets, particularly wind energy, have experienced remarkable growth, predominantly driven by the urgent need for decarbonization in the face of accelerating global warming. As the wind energy sector expands and turbines increase in size, there is a growing demand for advanced composite materials that offer both high strength and low density. Among these materials, graphene stands out for its excellent mechanical properties and low density. Incorporating graphene reinforcement into wind turbine blades has the potential to enhance generation efficiency and reduce the construction costs of foundation structures. As a pilot study of graphene reinforcement on wind turbine blades, this study aims to investigate the variations of mechanical characteristics and weights between traditional fiberglass-based blades and those reinforced with graphene platelets (GPLs). A finite element model of the SNL 61.5 m horizontal wind turbine blade is used and validated by comparing the analysis results with those presented in the existing literature. Case studies are conducted to explore the effects of graphene reinforcement on wind turbine blades in terms of mechanical characteristics, such as free vibration, bending, and torsional deformation. Furthermore, the masses and fabrication costs are compared among fiberglass, CNTRC, and GPLRC-based wind turbine blades. Finally, the results obtained from this study demonstrate the effectiveness of graphene reinforcement on wind turbine blades in terms of both their mechanical performance and weight reduction.

Selected challenges in solidification processing of graphene nanoplatelets (GNPs) reinforced aluminum alloys composites

Solidification processing of aluminum graphene composite is an attractive option for synthesis of metal matrix composites. Graphene reinforced aluminum metal matrix composites (GAMMCs) are of interest due to the low density and ultrahigh physical and mechanical properties of Graphene which can improve the properties of Al-Graphene composites. However, solidification processing of aluminum graphene composites has served challenges, including agglomeration of reinforcement and porosity resulting in decrease in properties above 0.five to three wt% graphene. Also, the graphene surface can react with molten aluminum alloys to form aluminum carbide. Challenges with particle distribution and porosity are frequently caused by the poor wetting of reinforcement by melt, requiring additions of selected wetting agents. The other problems include movement of reinforcement within the melt due to density differences and convection leading to nonuniform distribution of reinforcements. The graphene reinforcements can be pushed by solidifying interfaces under certain conditions during solidification leading to segregation of reinforcements in the interdendritic regions. The paper critically analyzes the above problems related to solidification processing of Aluminum- Graphene composites which has not been done in previous publications aluminum-graphene composites. The objective of this paper is to examine the challenges, and suggest possible solutions including addition of elements like silicon and magnesium to aluminum melt, coating graphene with metals like nickel and copper, controlling rate of advancement and nature of advancing solid liquid interface in a manner that they engulf graphene with dendrites or grains.

Determination of nano-graphene content for improved mechanical and tribological performance of Zn-based alloy matrix hybrid nanocomposites

The primary objective of this study is to explore the fabrication of a hybrid nanocomposite (HNC) composed of ZnAl40Cu2 alloy, graphene, and B4C particles, while also determining the optimal graphene reinforcement ratio for enhanced properties. Our methodology entails the production of HNC powders (HNPs) through mechanical milling, where we combine graphene nanoplatelets with B4C microparticles into ZnAl40Cu2 alloy powders. Throughout this process, we maintain a constant B4C content of 1.5 wt%, while varying the graphene content at 1.5 wt%, 3 wt%, and 4.5 wt%. Following the characterization of all produced powders, which includes an assessment of powder morphology, powder size distribution, and powder microhardness, we proceed to hot-press the HNPs to create bulk HNC samples. After consolidating the specimens, a comprehensive series of tests are carried out to determine microstructural, mechanical (hardness and tensile strength) and tribological properties. Our results reveal that the HNC specimen with graphene content of 3 wt% (referred to as A2) displays the most notable enhancements in properties. Specifically, A2 exhibits an impressive hardness of 163 HB, surpassing the hardness of the ZnAl40Cu2 matrix alloy, which measures at 133 HB. Furthermore, its ultimate tensile strength significantly outperforms the ZnAl40Cu2 matrix alloy, with a remarkable value of 223 MPa compared to 157 MPa. However, it is worth noting that the improvement in wear resistance for HNCs is most pronounced up to a certain threshold of graphene content, which is 3 wt%.

Thermal instability and vibration characteristics of laminated composite struts with Graphene reinforcements: An analysis of distribution patterns and geometrical imperfections

This study explores the effect of local buckling on the compressive performance of slender structural elements, particularly those with thin-walled sections. The phenomenon of local buckling significantly reduces the axial compressive stiffness, leading to a notable decrease in the load-bearing capacity of these elements. The main goal of this research is to examine how the post-buckling characteristics of polymeric composite channel section struts can be improved under thermal loading by incorporating multi-layer graphene reinforcements. The solution methodology incorporates the von Karman geometrical nonlinearity and is based on the layerwise third-order shear deformation theory (LW-TSDT). To ascertain the precision and computational performance of the results derived from LW-TSDT, a three-dimensional (3D) finite element model is created in ABAQUS for comparative evaluation. An extensive analysis of nonlinear thermal instability in perfect and geometrically imperfect FG-GRC laminated channel section struts is undertaken to discern the graphene distribution patterns that are most and least effective in elevating the critical buckling temperature and natural frequencies through pre- and post-buckling conditions. The comparative analysis indicates that employing the FG-X graphene distribution pattern across the thickness of the web and flanges in channel section struts leads to a projected increase of 12 % in the critical buckling temperature for clamped channel section struts, in contrast to those that adopt the FGO graphene distribution pattern. For cases with simply-supported boundary conditions, this increase is noted to be approximately 9 %. Moreover, findings confirm that incorporating an asymmetric graphene distribution pattern (FGV) or introducing geometrical imperfections in the flanges and web that generate a bending moment within the structure from the beginning of thermal loading effectively prevents the primary natural frequencies of FG-GRC channel section struts from declining to zero close to the critical buckling temperature. This is significantly different from scenarios involving perfectly structured and symmetrically reinforced graphene distribution patterns such as FGX.

Microstructural and mechanical properties evaluation of Calcium and zinc-modified WE43-based nanocomposites through stir casting for biodegradable applications

Magnesium-based alloys and composites have potential as biodegradable materials due to their moderate biodegradability, biocompatibility, and usefulness, but their mechanical strength limits their clinical use. The study synthesised a WE43-based alloy with calcium (Ca) and zinc (Zn), then reinforced it with nano reinforcements (hydroxyapatite, beta-tricalcium phosphate, graphene, and bioglass) through stir casting to create four nanocomposites. The microstructural and mechanical properties were examined to assess Ca and Zn's influence and determine the most effective reinforcement. The result showed that Ca and Zn-modified alloys and all nanocomposite materials have two additional phases, LPSO and Ca2Mg6Zn3, compared to the monolithic WE43 alloy. With the addition of Ca and Zn, S-2 saw significant increases in ultimate tensile strength (UTS), tensile yield strength (TYS), and uniform elongation (U.El), reaching ∼246 MPa, ∼144 MPa, and ∼8 %, respectively, while maintaining an elastic modulus of ∼19 GPa. This resulted in improvements of ∼29 %, ∼25 %, and ∼9 % compared to the as-cast WE43. Graphene-reinforced S-4 demonstrated superior mechanical properties with a UTS of 294 MPa, TYS of 194 MPa, U.El of ∼8 %, and an elastic modulus of 24 GPa, representing increases of ∼52 %, ∼69 %, and 6.05 %, respectively, compared to as-cast WE43. Additionally, S-4 exhibited impressive compressive properties, with an ultimate compressive strength (UCS) of 370 MPa, a compressive yield strength (CYS) of ∼185 MPa, and an U.El of ∼26 %. The bioglass-reinforced nanocomposites had a maximum hardness of 74.8 HV, whereas the as-cast WE43 had a maximum toughness of ∼4 J. These enhancements in mechanical properties are attributed to strengthening processes, including thermal mismatch, orowan, and grain refinement mechanisms. Graphene reinforcement shows promise for biodegradable applications.

Vibration Suppression of Graphene Reinforced Laminates Using Shunted Piezoelectric Systems and Machine Learning

The implementation of a machine learning approach to predict vibration suppression, as derived from nanocomposite laminates with piezoelectric shunted systems, is studied in this article. Datasets providing the vibration response and vibration attenuation are developed using parametric finite element simulations. A graphene/fibre-reinforced laminate cantilever beam is used in those simulations. Parameters, including the graphene and fibre reinforcements content, as well as the fibre angles, are among the inputs. Output is the vibration suppression achieved by the piezoelectric shunted system. Artificial Neural Networks are trained and tested using the derived datasets. The proposed methodology can be used for a fast and accurate prediction of the vibration response of nanocomposite laminates.