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In recent years, many different biomedical implants have been created for prolonged usage within the human body. The number of these implants has been steadily expanding. It is a common practice to use metallic bioimplants as substitutes when attempting to replace human body components in an anatomically acceptable manner. But the metallic bioimplant was mostly made biocompatible by putting a biocompatible coating on its surface and then using the right surface modification techniques. This was the primary method by which the biocompatibility of the bioimplant was achieved. Thermal spraying is a method that is frequently employed in surface modification treatments to modify metallic bioimplants. These methods can be found in the medical field. This is due to the adaptability of the thermal spraying method. Because of their capacity to respond and adapt to physiochemical circumstances, coatings that are based on hydroxyapatite (HAp) are the most popular type to be used in thermal spraying. This is due to the fact that HAp is a naturally occurring mineral. On the other hand, the majority of the HAp coatings are unsuccessful as a result of the coating’s weak mechanical qualities and insufficient adhesive strength. Supplying the coating in question with reinforcement in the form of hard particles and doing so in the appropriate proportions makes it feasible to alter the qualities of HAp-based coatings to fulfill a variety of requirements. This can be accomplished by providing the coating with reinforcement. The purpose of this inquiry was to deconstruct and analyze a variety of thermally sprayed (TS) coatings. These coatings were used to adhere HAp-based coatings on bioimplants. In addition, a detailed discussion is offered on how the reinforcements have an effect on the mechanical and biocompatible qualities of the coatings. In addition, we have discussed the difficulties associated with TS HAp coatings and their potential uses in the manufacturing of 3D biomedical implants through the utilization of cold spray (CS).

The development of lightweight and high-strength materials is critical for many industries, including aerospace, automotive, and electronics. Metal matrix composites (MMCs) have shown great promise in meeting these requirements. The structural and physical properties of Al6061 alloy reinforced with hybrid MMCs, including TiB2, SiC, and fly ash (FA), were investigated in this research review. The MMCs investigated were made using the stir-casting process. Their microstructure, structural characteristics, and mechanical features were examined. The inclusion of TiB₂ and SiC enhanced the composite’s hardness, tensile strength, and wear resistance, while the addition of FA lowered its density and improved its thermal and corrosion resistance. However, the volume percentage, particle dimension, and arrangement of the reinforcing components all had an effect on the physical characteristics of the composite. Therefore, the optimum combination of the reinforcing materials must be carefully selected to achieve the desired properties. The result of this review provides valuable insights into the development of high-performance MMCs for various industrial applications.

Metal Additive Manufacturing (MAM) has revolutionized the manufacturing of intricate three-dimensional structures. Sometimes, the material properties and microstructures of metals produced by additive manufacturing (AM) are often worse than those created using traditional manufacturing methods. Mechanical characteristics and microstructure of AM-made metals can be enhanced with post-heat treatment (PHT). This paper reviews and discusses the various types of PHT techniques, including solution treatment (ST), aging, Isostatic Hot Pressing, and precipitation hardening. In this study, several characterization methods, such as mechanical testing, hardness testing, scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM), are utilized to investigate how the microstructure and mechanical properties of the printed components change after being subjected to PHT. The study results give important information about each selected metal’s most effective heat treatment conditions. This lets the microstructure and mechanical properties of the printed parts be tuned effectively. The paper has reviewed the various PHT effects in MAM on various metallic materials such as Stainless Steel, Maraging steel, Aluminum, and Titanium alloys.

The lack of ductility is known to be one of the major drawbacks of amorphous state. Recently, an increase in the tensile strength and ductility was found in the ${\text{Ni}}_{82.1}$${\text{Cr}}_{7.8}$${\text{Si}}_{4.6}$${\text{Fe}}_{3.1}$${\text{Mn}}_{0.2}$${\text{Al}}_{0.1}$${\text{Cu}}_{0.1}$B₂ metal glass ribbon pre-annealed at $\beta$-relaxation temperature. This paper analyzes the surface relief transformation observed during this process and the nature of separate inhomogeneities. The most significant effect is a flattening of the surface relief. This case was confirmed by statistical processing. Thus, the surface relief change was shown to be a clear indicator of structure relaxation process, that occurs in a metal glass ribbon well below its crystallization.

Aluminum alloys are widely used in the automotive and aerospace industries due to their lower mass-to-strength ratio than other metallic alloys. Apart from their inherent properties, aluminum alloys like other metallic alloys show a significant change in their mechanical properties according to the machining parameters. The research literature on obtaining optimum mechanical properties of aluminum alloys that undergo machining is very limited. Moreover, the combined effect of several parameters on the machinability of aluminum alloys has not yet been explored. In this paper, the effect of three machining parameters (Depth of Cut (DoC)), feed rate (FR), and cutting speed (CS) on the subsurface damage and fatigue life of aerospace-grade aluminum alloy (Al-6082-T6) is observed. Samples are prepared using a full fractional approach to effectively capture the effect of all input parameters. Thereafter, samples were subjected to surface roughness, micro-hardness, and fatigue life tests. Results of surface roughness and micro-hardness tests are compared with fatigue life. The general linear model was employed to capture the percentage effect of each input parameter on the output parameters. The results showed that DoC was the main contributing factor that caused subsurface damage, while surface roughness and fatigue life were mainly affected by FR and CS. Optical microscope images showed a white layer formation that had higher hardness than the base metal. Overall, this research work proposes the input parameters that can be used to achieve minimum surface damage and fatigue life.

This study investigates the performance of vinyl ester composites reinforced with areca fruit fiber, microcrystalline cellulose, and silane coupling-grafted recycled PET bottle waste foam under conditions of water and heat-accelerated aging. The reinforcement, areca fiber and recycled PET foam were surface-modified using 3-aminopropyltrimethoxysilane (3-APTMS) to enhance interfacial bonding. The composites were fabricated using a manual hand layup process and subjected to aging tests. According to results the APS2 composite had enhanced heat conductivity at 0.17W/mk and decreased flame propagation speed at 10.99mm/min after being exposed to saltwater. Similarly, after being exposed to rainwater, the ARP2 composite developed a temperature conductivity of 0.16W/mk, a flexural strength of 80.3MPa, a tensile strength of 37.4MPa, and a flame propagation speed of 10.97mm/min. SEM analysis of silane-treated vinyl ester composites reinforced with areca fibers and microcrystalline cellulose reveals improved interfacial bonding and filler dispersion, enhancing the composite’s mechanical integrity. These findings confirm that the application of silane coupling agents significantly enhances the thermal stability, water resistance, and overall durability of the composites, making them suitable for demanding applications requiring high mechanical strength, effective thermal management, and robust fire resistance, particularly under challenging environmental conditions.

Diffusion bonding of AA7075/AZ80 joint has been synthesized, studied and demonstrated to optimize the lap shear, Ram tensile and hardness properties. Response surface methodology (RSM) is applied to develop mathematical relationships between the control parameters of two factors and three-level responses. Optimization experiments were carried out to check the models’ adequacy. The results show a high degree of coincidence between the optimized and actual values, implying that the proposed models can accurately forecast lap shear, Ram tensile, and hardness properties force within the process parameter constraints of the diffusion bonding process. Scanned electron microscopic Scanning Electron Microscope (SEM) images, optical images, and radiography film photography investigations also revealed the excellent fracture resistance of the AA7075/AZ80 alloy, making it a suitable material for deployment in engineering applications.

This research investigates the mechanical properties of Boron Nitride Nanosheets (BNNS) by integrating molecular dynamics (MD) simulation with machine learning (ML) techniques. The work highlights the impact of various factors, including dimension, temperature, strain rate and chirality orientation and their influence on mechanical properties like fracture stress, fracture strain, ultimate tensile strength, and Young’s modulus within the context of nanoelectromechanical systems (NEMS). The novel combination of MD simulations and ML models  — specifically decision trees, random forest, support vector machines, and polynomial regressions demonstrates that temperature significantly impacts the Young’s modulus, and strain rate estimates true agreement with theoretical expectations. These results highlight machine learning potential to advance material property predictions providing a new methodology for interpreting mechanical properties at the nanoscale and paving the way for innovative applications in NEMS.

In this study, metal oxides of Strontium oxide (SrO) and Lanthanum oxide (La₂O₃) were incorporated into a polymer blend of polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), and polyethylene glycol (PEG). Specifically, the blends PVA-PVP-PEG, PVA-PVP-PEG-SrO, PVA-PVP-PEG-La₂O₃, and PVA-PVP-PEG-SrO-La₂O₃ were prepared using casting techniques enhanced by ultrasonic casting methods. The resulting polymer membranes exhibited both semi-crystalline and amorphous characteristics, with the addition of SrO and La₂O₃ leading to prominent crystalline peaks. The electrical properties of these polymer blends were analyzed using impedance spectroscopy and an I-V source meter, which allowed for the determination of their resistance ranges. Notably, the PVA-PVP-PEG-SrO-La₂O₃ membrane exhibited a significant elongation of 102.6%, as indicated by Young’s modulus measurements, underscoring its potential use as an active layer for flexible electronics applications.

Gas metal arc welding (GMAW) was used to fabricate Zircaloy-2 pipe, producing flawless welds applicable in the nuclear, aerospace, and marine industries. This technique was optimized by testing a great deal and identifying the ideal process parameters (13.6V, 135A, 3mm arc length and welding speed of 170mm/min). Optical microscopy of the welded microstructure of the material demonstrated the presence of columnar and equiaxed dendrites near the weld metal (WM), mostly constituted of $\alpha$-zirconium and $\beta$-zirconium phases. The mechanical properties of welded pipe have been considerably improved by these microstructural changes, which are the result of constitutional supercooling and thermal histories. Tensile strength of weldment increased by 4.3% to 501.9MPa, while base metal (BM) showed 485.2MPa of strength. Results of the tensile test show a simulated error percentage of less than 1%. Notably, the welded pipe showed better mechanical strength than BM, and a 180^∘ bend test proved its ductility by revealing no symptoms of cracking. Evaluations of microhardness revealed a decrease in hardness in the BM area (179–186HV), in contrast to maximum values found in the WM (219–243HV).

The enactment of natural fibers as a replacement for conventional synthetic fiber has aroused the interest of academicians and researchers to look out for newer materials. Surface modification of inflorescence fiber with 5% wt/vol of aqueous solution eliminated the functional elements present. An increase in crystal size of 17.84% was observed between untreated and alkali-treated inflorescence fibers. FTIR characterization revealed an increase in stress transfer capacity by the elimination of hemicelluloses, lignin, pectin and other amorphous substances. The addition of inflorescence fiber up to 20 wt.% with 10 wt.% of sisal fiber and 70 wt.% of epoxies solicited towards utter tensile strength of 48.42MPa and flexural strength of 72.69MPa. Around 51.98% increase in tensile strength was recorded between S0 (neat epoxy) and S4 (10% sisal and 20% inflorescence fiber) composites. Similarly, a 39.18% increase in flexural strength was estimated between S0 (neat epoxy) and S4 (10% sisal and 20% inflorescence fiber) composites. SEM analysis reported the formation of rough surfaces and cavities on the inflorescence fiber surface owing to NaOH modification of fibers. Fiber pullouts were also recorded in 25 wt.% reinforced inflorescences/sisal fiber fortified epoxy composites which attributed to a sudden decrease in tensile and flexural properties.

This study investigates the mechanical, fatigue, and microstructural properties of friction stir welded dissimilar AA6061-AZ31B Mg alloy, incorporating cassava waste biosilica. The principal aim of this research study was to analyze the reinforcement effect of biosilica in the weld pool of dissimilar AA6061-AZ31B Mg subjected to friction stir welding process. The biosilica of size 30–40nm was synthesized from the waste of cassava peel via thermo-chemical process and characterized. The welding process was performed as a butt joint configuration with the biosilica filled via the root canal. According to the results, the weld bead AA2 demonstrates notable tensile and yield strength of 252 and 218MPa, respectively, with a notable elongation of 4.4%. Despite this, it shows a maximum impact energy of 17.8J, signifying favorable toughness. Biosilica inclusion enhances hardness, peaking at 112 VHN for weld composition AA3, crucial for wear resistance. Composition AA2 exhibits noteworthy fatigue strength at 158MPa, vital for industries like automobile and defense. The microstructure of welds revealed changes in grain size and toughness improvement after the addition of biosilica. The EDAX report confirms the presence of Si, Al, and Mg atoms in the nugget zone. The weld composition AA2 showcases promising mechanical properties, suggesting its suitability for demanding applications in these sectors. In summary, biosilica incorporation in friction stir welding enhances mechanical properties, providing useful strength improvement for commercial and novel MMCs developed for robust applications.

Friction stir welding (FSW) has become one of the most used solid-state joining methods because of the increased mechanical properties and weld quality that can be obtained. The present investigation focuses on the effects of Titanium Carbide nanoparticles (TiCnp) reinforcement with the welds of AZ31 magnesium alloy using the grey relational coefficient optimization technique with the aid of artificial neural networks (ANNs) for modeling. The parameters considered are TiCnp content of approximately 1.5wt.%, tool inclination angle of 0^∘, 1^∘, and 2^∘, tool spindle speed of 1000, 1250, and 1500rpm, tool geometry square, cylinder, and triangle, feed rate of 25, 50, and 75mm/min and axial force of 5, 10, and 15kN. Other mechanical properties determined involve microhardness, Tensile Strength (TS), wear rate (WR), and impact strength (IS). The results show the improvement of mechanical properties with an increase in TiCnp concentration within the range which implies that the highest TS of 242MPa is obtainable when the amount of TiCnp is optimally added. Interestingly, while identifying the optimal parameters for mechanical properties, it was ascertained that 1250rpm of rotational speed (RS), 50mm/min of traverse speed (TS), 1^∘ of tilt angle (TA), and square tool profile shape were found to have the best results. Similar findings were backed up by the ANN models whereby the introduction of TiCnp into the AZ31Mg alloy boosts TS to about 130MPa, microhardness to 70MPa and IS to about 89.34MPa, and lowers WR to 0.0046m³/m. This integrated approach highlights the possibility of applying ANN coupled with grey relational analysis for the improvement of FSW process for improving the material characteristics.

This study investigates the mechanical, fatigue, water absorption, and flammability properties of polyethylene terephthalate (PET) core-pineapple fiber sandwich composites reinforced with silane-treated neem fruit husk (NFH) biosilica additives. The novel approach includes modifying the fiber’s surface and incorporating biosilica to enhance environmental resistance. The composites were prepared using a hand layup method, followed by silane treatment of the biosilica, pineapple fiber, PET core and vinyl ester resin. Subsequently, to evaluate environmental impacts on composite’s performance, sandwich composites were subjected to temperature aging at 40^∘C and 60^∘C in a hot oven for 30 days and warm water aging at the same temperatures in tap water with pH 7.4. According to the results, adding 1%, 3%, and 5 vol.% silane-treated biosilica significantly improved the mechanical properties. The composite with 3% biosilica (L2) showed a tensile strength of 120.8MPa, flexural strength of 194.4MPa, compression strength of 182.4MPa, rail shear strength of 20.21MPa, ILSS of 23.14MPa, hardness of 85 Shore-D, and Izod impact strength of 6.56 J. Even under temperature and water aging conditions, the composites showed only minimal reductions in properties, highlighting the efficacy of the silane treatment. The temperature-aged L2 composite had a tensile strength of 104MPa, flexural strength of 172.8 MPa, compression strength of 164MPa, and ILSS of 22.5MPa, while the water-aged L2 composite exhibited a tensile strength of 96MPa, flexural strength of 152.8MPa, compression strength of 146.4MPa, and ILSS of 21.4MPa. Scanning electron microscope (SEM) analysis confirmed uniform dispersion of biosilica particles, critical for improved performance, though higher concentrations led to agglomeration and stress points. The composites also demonstrated excellent flame retardancy, maintaining a UL-94 V-0 rating with decreased flame propagation speeds, specifically 9.05mm/min for L2. These findings underscore the potential of silane-treated biosilica as a reinforcing additive to enhance the durability and performance of composites in adverse conditions.

Nowadays, there is a growing need for using functionally graded materials (FGM) for using in bio-medical application. This need is prominent especially for the effect of gradient structures and in implant applications. To optimize both mechanical and biocompatibilities properties or change bio reactivity in each region, powder metallurgy technique is used in this study to fabricate titanium/hydroxyapatite (Ti/HAP) and other FGM implants with the concentration changed gradually in the longitudinal direction of cylindrical shapes. Concentration gradient was formed by packing dry powders into mold or sedimentation in solvent liquid processes. For the sintering process, three spark plasma sintering (SPS), high-frequency induction heating and electric furnace heating techniques were used to sinter the materials. During the fabrication of Ti/HAP FGMs and due to the stress relaxation in the implanted regions of bones, Brinell hardness decreased gradually from Ti part to HAP part. The results showed that the tissue reaction occurred gradiently in response to the graded structure of the FGM, which implies the possibility of controlling the tissue response through the gradient function of the FGM.

Interlocking Shear Groove (ISG) between base plate and main beam serves as the connection for interaction between the longitudinal slab ballastless track (LSBT) and bridge structure. To study the failure characteristics of ISG under low cyclic loads, a test model with a 1:5 scale ratio of base plate-ISG-main beam with 4 different numbers of shear bars was designed and made. Failure mechanism, failure pattern, hysteresis curve, skeleton curve, and other failure characteristics of the ISG under low cyclic loads were studied. Based on test data multiple regression of ISG, the three-fold theoretical skeleton model and the formula were established. By analyzing the hysteretic characteristics of ISG, the hysteretic rule and stiffness degradation rule of loading and unloading are obtained, and then the restoring force model was established and verified. The results show that the failure pattern of the ISG is divided into three stages: (a) appearance of fine cracks on both sides of the interface between the ISG and main beam; (b) with the increase in loading displacement, the interface between the ISG and main beam underwent shear cracking and developed into through cracks, and the shear bars underwent shear deformation; (c) the ISG cracked and failed under the combined action of bending and shear, the upper component tilted, and the shear bars underwent bending and shear deformation. Increasing the number of shear bars in the ISG effectively increased the bearing capacity and stiffness and improved the ability to resist external loads. This led to an effective reduction in the strength and stiffness degradation rate. With the increase in the number of the shear bars, the energy dissipation ratio and energy dissipation capacity of the ISG increased, the better the seismic performance of the specimens. The established three-fold model theoretical skeleton model and the restoring force model of the ISG are in good agreement with the test data, and the calculation method of the model is simple and clear, which effectively reflects the hysteretic performance of the ISG under low cyclic loads. The research results can provide theoretical basis for seismic damage analysis of the LSBT — bridge system of HSR.

This paper presents a novel approach to enhance the energy absorption (EA) of honeycombs in the out-of-plane direction. Inspired by the Koch fractal, a fractal hexagonal honeycomb (FHH) is presented in this paper. In our study, we use Abaqus/Explicit to build a finite element model of the honeycomb, through which we conduct a series of studies on the performance of this honeycomb. Initially, we compare the mechanical properties and deformation modes of the FHH with those of a conventional hexagonal honeycomb. The results demonstrate notable improvements in crashworthiness metrics for the FHH, including a 52% increase in specific EA, a 45% enhancement in crushing load efficiency (CLE), and an 8% reduction in peak crushing force (PCF) compared to the conventional counterpart. Subsequently, this paper investigates the fractal arc honeycomb and evaluates the effect of the center angle on mechanical properties by varying its value. Furthermore, the mechanical properties of layered honeycomb and fractal honeycomb structures with different wall thicknesses are systematically examined. In the last section, we explore the theoretical analysis of the fractal-hexagonal honeycomb and find that the results of the theoretical analysis are in good agreement with those of the simulation, indicating that the experimental simulation results are reliable. Overall, the findings of this study offer valuable insights for the innovative design of hexagonal honeycomb structures, providing a reference for future advancements in this field.

The operation and service performance of ballasted track on bridges face significant challenges due to high-speed railway train operations. To investigate the mechanical characteristics of ballasted track on bridges, field experiments were conducted. A coupling model of ballasted track on a simply-supported girder bridge was established using the coupling method of discrete element and multi-flexible body dynamics and analyzes the changes in ballast bed settlement deformation, stiffness and energy with increasing load cycles. The findings reveal that dynamic loading alters the original contact state of ballast particles, displaying notable anisotropy vertically and longitudinally and isotropy horizontally. The vibration of ballast particles on bridges is more pronounced than on the subgrade, with vibration acceleration under the sleeper at 150mm depth on the bridge being 2.89 times that on the subgrade foundation. As the system stabilizes, the interlocking effect among granular ballast particles strengthens, reducing mutual sliding and increasing ballast bed stiffness by approximately 7.8–9.5% compared to the initial state, while total energy and dissipated energy gradually decrease. It is recommended to monitor the quality of ballast particles under the sleeper of ballasted tracks on bridges, implement vibration mitigation measures, or periodically replace ballast particles.

In order to accurately test the mechanical properties of Q420 steel under static tensile conditions, a universal testing machine is used to conduct room temperature static tensile tests on Q420 steel at different strain rates of $0.0001{\mathrm{\text{s}}}^{-1}$, $0.001{\mathrm{\text{s}}}^{-1}$ and $0.01{\mathrm{\text{s}}}^{-1}$. The corrected constitutive model is substituted into ABAQUS software for tensile finite element simulation analysis. The accuracy of Esmaeily-Ghasemabadi (E-G), Hollomon, Swift and Voce empirical constitutive models was evaluated based on the stress–strain curve. The Hollomon model with small error and the Voce model with a large fitting proportion and relatively stable error were selected, combined with strain rate sensitivity functions from Power law, Wagoner and Johnson–Cook/Modified (J-C/M) models for modification. The quantitative analysis has verified that the modified model combining the Power law model with the Voce model was optimal. The correlation coefficient ($R$) of the Voce-Power (V-P) model before necking was consistently 1, and the average absolute relative error ($e_{\mathrm{\text{ARRE}}}$) had decreased to $0.095\%$. The modified V-P model could reliably describe the stress–strain behavior of bcc structure metals. The error of mechanical strength value between calculation and experiment was within $0.4\%$ during the strengthening stage, and the average $e_{\mathrm{\text{ARRE}}}$ of curve fitting was $0.734\%$. This work held great significance for accurately predicting the mechanical properties of Q420 steel in different load conditions, optimizing structural design and ensuring engineering safety. In particular, it was crucial for establishing accurate stress–strain responses in the fatigue life simulation process of wind turbine towers.

The Integrated Computational Materials Engineering (ICME) approach is implemented to develop an integrated model for the processing of steel at a hot strip mill. The effect of temperature, deformation, and subsequent cooling rate on microstructure and its associated properties of the steel are mapped using analytical, numerical as well as machine learning approaches, all applied in tandem. The modeling approaches include a rigid visco-plastic approach for the flow formulation, finite volume method to calculate temperature distribution profile, artificial neural network (ANN) modeling for predicting CCT diagram, and Mecking–Kock model along with stress mixing law for the structure–property correlation. The composite model for mapping the final microstructure and microstructure-dependent properties of the steel, which depends on the composition, and various parameters of the hot strip mill is validated through a comparison of predicted values with the published results. The work shows that the hybridization of constitutive equations with the data-driven approach in ICME can successfully model a complex system like the hot strip mill.