Bamboo fiber-reinforced composites have emerged as environmentally friendly, plentiful, and high-mechanical-performance materials used in recent years. This review presents an overview of the mechanical and water uptake properties of bamboo fiber polymer composites and bamboo/glass fiber/nanoclay hybrid composites to consider their structural and industrial applications. Bamboo fibers have better mechanical properties compared to polymers. Moisture absorption and fiber surface treatments influence their long-term functionality. Hybrid composites of bamboo, glass fibers, and nanoclay have revealed synergistic mechanical and water uptake properties. Adding nanoclay enhances interfacial adhesion and prevents void formation, improving overall mechanical performance. This review also discusses the impact of hybridization ratios and fiber surface treatments on bamboo fiber composite behavior. The results suggest that, whereas bamboo fiber polymer composites are suitable for applications requiring lightweight composites, hybrid composites exhibit better mechanical properties to be used in advanced engineering applications. Future research topics will include the optimization of hybrid compositions and sustainable treatment strategies to enhance the performance and longevity of these composites further.

Fiber-reinforced polymer composites are subjected to harsh environmental conditions over the course of their designed lifespan. Studying the aging process of fiber-reinforced polymer composites exposed to boiling water is critical for improving their durability. This study uses a hand lay-up technique to fabricate composites from glass fiber, bamboo fiber, nanoclay, and epoxy. Tensile and flexural tests are conducted following ASTM standards. The % of water uptake of the boiling water-soaked specimens is measured, and the performance of the dry composites is compared with those of boiling water-soaked composites. The results show that boiling water-soaking conditions have an adverse impact on all the composites. Boiling water-soaked epoxy samples show a reduction in tensile properties by 25 and 30% and flexural properties by 18 and 22% under processes 1 and 2 of boiling water soaking, respectively, compared to dry ones. Meanwhile, for fiber-reinforced composites, the tensile properties decrease by 19 and 27%, and the flexural properties decline by 12 and 20% under processes 1 and 2 of boiling soaking, respectively. However, incorporating nanoclay enhances the tensile and flexural properties of the epoxy and the composites by 5 to 7% and 10 to 12%, respectively. The water absorption rate and the impact of boiling water-soaking on composite strength decrease with the addition of nanoclay. Additionally, nanoclay reduces the percentage of reduction in tensile properties by 17 and 26% and in flexural properties by 11 and 18% under processes 1 and 2 of boiling soaking, respectively. SEM analysis of the fracture surfaces reveals the causes of specimen failure under tensile load, with distinct differences between dry and boiling water-soaked specimens.

The aim of this work is to investigate the variations in microstructure, hardness, wear and surface roughness between as-cast and heat treated trace elements added A356 alloy. Alloy A was prepared by adding 1 wt.% magnesium to A356 alloy which was used as the base material for the preparation of alloys with zinc (Zn) and copper (Cu) particles as alloying elements. Other set of samples was fabricated where Cu-coated Zn and Cu were added as reinforcements to base matrix A. The microstructural analysis indicated that the addition of Zn to A356 as an alloying element had a limited effect on controlling the grain size during solidification compared to Cu. The addition of Cu as reinforcement resulted in a higher proportion of pro eutectic α-Al phase, leading to finer grain boundaries. Micro-polishing test was conducted on the alloys and composites by determining the surface roughness (Ra) value using profilometer to study the changes in surface roughness under individual load conditions of 20 and 40 N. In the as-cast condition, the addition of Cu increased the hardness by 39% and 58% over the base alloy, respectively. Age-hardening treatment significantly enhanced the wear resistance properties of unreinforced alloys and composites at both aging temperatures, especially at 100 °C. Composite samples exhibited excellent surface finish (lower surface roughness) compared to alloy samples, attributed to the presence of hard reinforcement particles.

Austempered ductile iron is an innovative material obtained by subjecting it to an austempering heat treatment. The wide application of this material is because its properties are comparable to those of steel, which has a much lower weight. However, the machinability of this material is always a difficult task owing to its high hardness. This problem becomes more complex when a considerable amount of Mn is added. In this study, a novel two-step austempering heat treatment was performed on spheroidal graphite iron containing different amounts of manganese. Although the novel heat treatment method helps to obtain a superior combination of hardness and impact, its effect on machinability must be determined. This study provides the results of machinability tests carried out on austempered ductile iron with various manganese contents produced using the novel method. Scanning electron microscope images of the microstructures revealed a typical ausferrite structure with no segregation of manganese at the grain boundary. This is evident from the good tool life obtained in the machinability tests. Regression equations are fitted to determine the tool life and surface roughness for machining parameters with a range of values considered in this study. The results obtained have shown that till 1 wt% of manganese alloyed austempered ductile iron can be successfully produced using the novel heat treatment method. This helps to obtain the optimum combination of strength and impact properties.

The environmental threat of discarded tires needs to be addressed through alternative applications with the enormous increase in the global vehicle population. When tire rubber particles are combined with environmentally friendly, and biodegradable natural fibers in polymer composites, such materials have a lot of potential for use in a variety of applications of insulating structures. The current work explores the effect of adding waste tire rubber particles (TRP) to natural fiber-based hybrid composites, on mechanical and acoustic properties and investigate the possibility of a potential insulating structural material. Tire rubber particles were employed as fillers and chopped banana fibers as reinforcing fibers (particle size less than 400 m) with epoxy resin as the matrix in this work. Five compositions were formulated in which the TRP content was varied from 0 to 36 wt.

This study employed a two-stage stir-casting technique to fabricate experimental alloys and composites using A356 + 1 wt.% Mg as the base alloy and trace copper/zinc as alloying elements and reinforcements. Peak aging conditions were applied through a solutionizing process at 520 degrees C and subsequent aging at 100 degrees C and 200 degrees C. A wear test was conducted using a pin-on-disk tribometer under dry sliding conditions to measure wear and frictional force. The ANSYS software simulated the wear, demonstrating a close approximation to the experimental values. The study emphasized the influence of material hardness and coefficient of friction on the wear coefficient accuracy. A higher hardness yielded closer simulated experimental values, whereas lower friction coefficients enhanced convergence. The increased contact pressure and frictional stress were accompanied by higher applied loads. The study suggests future exploration of thermal changes in frictional contact regions and incorporation of surface irregularities in realistic simulations, requiring advanced computing tools.

Precision machine tool structures require enhanced stability with higher static stiffness and increased damping. Granite epoxy (G-E) composite offers improved damping properties and is a promising alternative material. This study evaluates the mechanical strength and damping of G-E hybrid polymer composites with varying percentages of cast iron (CI) filler. Experimental and finite element (FE) analyses were conducted on hybrid composite samples incorporating 5, 10 and 15 wt% CI filler particles. Results show that a 70:30 ratio of G-E with 10% CI filler enhances compressive strength. Tensile and flexural behaviors are influenced by epoxy content, with minimal effects from CI filler. Both experimental and numerical simulations show significant improvement in stiffness and damping properties with higher quantities of granite particulates (80 wt%) and 5 wt% CI filler. Modal analysis confirms higher natural frequencies in all modes. This hybrid composite configuration presents a viable alternative for machine tool structures, offering increased structural damping.

Among the various types of recently released composite materials, particle-reinforced metal matrix composites (MMCs), in particular aluminum as the matrix material, have been shown to provide substantial industrial benefits in the automotive and aerospace sectors. The current research focused on the corrosion behavior of an Al7075 hybrid composite in 0.1 M hydrochloric acid (HCl) and 3.5% NaCl media at different temperatures. Electrochemical techniques, such as Tafel polarization (TP) and electrochemical impedance spectroscopy (EIS), were employed to study the corrosion behavior in the respective solutions. The results showed that the corrosion rate of the studied specimen increased from 31.77 to 47.61 mmy−1 in 0.1 M HCl and from 0.26 to 1.28 mmy−1 in 3.5% NaCl with increasing temperature. The corrosion current density of the Al7075 hybrid composite in 0.1 M HCl is on the order of 10−3 Acm2, and that in 3.5% NaCl is on the order of 10−5 Acm2. This confirms the increased rate of composite corrosion in the 0.1 M HCl medium compared to that in the 3.5% NaCl medium. A suitable mechanism was proposed for the corrosion of the Al7075 hybrid composite in both media.

Aluminium–Silicon (Al-Si) eutectic alloy matrix composites are widely used in engineering application. However, it is a well-known fact that this material is not heat-treatable. In order to take advantage of the improvement in the mechanical properties due to the heat treatment, it is essential to find a way to make the Al-Si composite heat treatable. The dissolution of magnesium in the matrix, makes the composite age-hardenable, showing improvements in hardness and tensile strength properties according to changes in aging kinetics. This study analyses the peak aging kinetics on the hardness-related property improvement according to the magnesium dissolution content in the matrix. Hence, this research focuses on the role of aging treatment on the mechanical properties, especially the hardness of stir-cast Al-Si matrix Silicon Carbide (SiC) composites with up to 1.5 wt. % Mg intentionally dissolved in base alloy. Two aging temperatures (100 and 200 °C) were pitched into the target peak hardness and peak-aged condition. A minor quantity of Mg dissolution in the Al-Si matrix SiC composite has resulted in the improvement of hardness up to 24%, and age-hardening conditions contributeed up to a 40% increase in peak hardness. Similarly, the peak aged condition tensile strength shows an increase of up to 45% during age hardening compared to the Mg-free as-cast composite.

Fiber-reinforced polymer composites (FRPs) experience exposure to diverse environments throughout their intended design life. Investigating the aging process of FRPs immersed in water is crucial for enhancing the material's durability. In this study, glass fiber, bamboo fiber, nanoclay and epoxy composites are produced using the hand lay-up process. Tensile and flexural tests are performed in adherence to ASTM standards. The water uptake percentage of soaked specimens is computed, and a comparison is drawn between the results of dry and water-immersed composite specimens. Water-soaking condition negatively affects all the composites. Water-soaked specimens exhibit lesser tensile and flexural strengths than dry specimens by 7.4-14.8% and 7-13.6%, respectively. The addition of nanoclay further improves the tensile and flexural strengths of epoxy and all composites by 6-11%. Water uptake (%) and water-soaking effects on the strength of composites decline when nanoclay is added. The addition of nanoclay declines the percentage of reduction of tensile strength from 8.6-14.8% to 7.4-12%. Similarly, the percentage of flexural strength reduction declines from 8-13.6% to 7-11%. The dry and water-soaked specimens' fracture surfaces (Scanning Electron Microscope [SEM] images) show significant variations.

This review offers a summary of the epoxy-nanoclay nanocomposites research that has been performed. Epoxy-nanoclay nanocomposites have an across-the-board variety of aerospace, defense, construction, and automobile applications. Nanoclay is one of the ideal nano-reinforcement for epoxy because of its ease of workability, environmental accessibility, well-versed chemistry, and lower cost. The significant addition of a smaller quantity of nanoclay, mostly & LE;5 wt.%, may efficiently improve polymer composites' properties. This review aims to provide a state-of-the-art overview of epoxy-nanoclay nanocomposites, including their preparation methods, mechanical, hygrothermal, and wear properties. The discussion highlights the nanoclay influence on the properties listed above and the morphology of epoxy-nanoclay nanocomposites.

The present study reflects on the wear behaviour characteristics of A356 composite with trace addition of copper and copper-coated zinc as reinforcements. Dry sliding wear tests were conducted on fabricated as-cast and heat treated composites by varying load of 20-60 N under constant sliding speed of 1 m/s and sliding distance of 3000 m. Results confirmed that copper-coated zinc was successfully introduced as reinforcement into A356 matrix using two-step casting method. Scanning Electron Microscope (SEM) images confirmed the presence and homogeneous distribution of the added reinforcements in the matrix. T6 treatment with addition of Cu reinforcement facilitated age hardening showing 121% hardness improvement compared to as-cast matrix A356. At lower loads, wear results showed 117-134% enhanced wear resistance in composite reinforced with 1 wt.% Cu and aging at 100°C. However at higher loads, 153-210% improvement in wear resistance was observed. Overall, copper and Cu-coated zinc reinforced composite along with T6 treatment exhibited significant improvement in hardness wear property compared to as-cast matrix A356 alloy.

This research work highlights the prediction of hardness behaviour of age-hardened LM4 and its composites fabricated using a two-stage stir casting method with TiB2 and Si3N4. MATLAB - Artificial Neural Networks is used to predict the age-hardening behaviour of LM4 and its composites. Experiments (hardness and tensile tests) are conducted to collect data for training an ANN model as well as to investigate the effect of reinforcements and age-hardening treatment on LM4 and its composites. The results show that with an increment in the reinforcement wt.%, there is an enhancement in hardness and ultimate tensile strength (UTS) values within the monolithic composites. As-cast hybrid composites display a 37 to 54% improvement in hardness compared to as-cast LM4. Heat-treated samples, specifically those treated with peak aging with MSHT and 100°C aging, perform better than as-cast samples and other heat-treated samples in terms of UTS and hardness. Compared to as-cast LM4, MSHT, and 100°C aged samples display an 85 to 202% increment in VHN. Hybrid composites perform better in terms of hardness, while composites with 3 wt.% of TiB2 (L3TB) perform better in terms of UTS, peak aged (MSHT and 100°C aging) L3TB display 68% increment in UTS when compared to as-cast LM4. ANN model is developed and trained with five inputs (wt.% of TiB2, wt.% of Si3N4, type of solutionizing, aging temperature, and aging time) and one output (VHN) using different algorithms and a different number of hidden neurons to predict the age hardening behaviour of composites. Among them, Lavenberg-Marquardt (LM) training algorithm with normalized data and 30 hidden neurons performs well and shows a least average error of 1.588364. The confirmation test confirms that the trained ANN model can predict the output with an average %error of 0.14 using unseen data.

The present work mainly focuses on a comparative study of the individual and combined effect of reinforcements on tensile strength and fracture surface analysis of Al6061 alloy and its composites during artificial aging. SiC and B4C are the two reinforcements used in the present work for the preparation of Al6061 composites by the stir casting process, and the reinforcement percentage from 2, 4, and 6 wt.% varied. Both Al6061 alloy and its composites are solution-treated at 558 °C/2 h and artificially aged at 100 and 200 °C for different time intervals to achieve peak aging. The results show substantial improvement in ultimate tensile strength during low temperature aging at 100 °C. Approximately 80–110% increase in UTS value is observed in both individual and hybrid composites compared to Al6061 alloy. The mechanism of failure governing the tensile strength for both alloy and its composites is thoroughly analyzed and discussed using a scanning electron microscope. The morphology of crack propagation is also studied to determine the mechanism of failure. Al6061 alloy shows ductile failure due to coarser dimples. Al6061-SiC composites show particle-matrix interface cracking and shear failure. Al6061-B4C composites show elongated dimple rupture mode of failure, whereas Al6061-SiC + B4C hybrid composites fail due to nucleation growth and mixed fracture mode.

This technical paper demonstrates the possibilities of nickel (Ni) coated Al2024 powder reinforcement in an Al7075 matrix using the liquid stir casting technique. Additionally, the paper focuses on achieving stable properties by implementing artificial aging heat treatment. To apply the Ni coating, the electroless nickel plating technique was utilized, and a minimum coating thickness of 8 μ m was determined to effectively prevent the dissolution of Al2024 powder reinforcements within the Al7075 matrix. Stir casting facilitated the uniform dispersion of the coated Al2024 powder up to a weight percentage of 7%. Subsequently, the Al7075 alloy and composites underwent artificial aging through solution heat treatment (SHT) at 450 °C for 4 h, followed by water quenching and aging at temperatures of 120, 150, and 180 °C. Aging at 120 °C was found to yield superior results compared to aging at 150 and 180 °C, thus identified as the optimum aging temperature. When the Ni coating thickness was increased beyond the optimal 8 μ m, the resulting enhancements in hardness for both as-cast and peak-aged specimens, as well as the tensile strength, were not significant. The improvements observed were only marginal, ranging between 2 to 3%. Fracture surface analysis revealed that the predominant fracture mode in the Al7075 alloy was ductile, characterized by dimple rupture. In the as-cast Al7075-(7%, 8 μ m) Al2024 composite, a mixed fracture mode comprising both brittle and ductile characteristics was observed. In the peak-aged (120 °C) Al7075-(7%, 8 μ m)Al2024 composite, the overall fracture mode exhibited a dominant brittle nature. Analytical techniques including XRD, TEM, and EDS confirmed the presence of Mg _2 Si, MgZn _2 , CuAl _2 , and CuAl _2 Mg phases in the peak-aged (120 °C) Al7075-(7%, 8 μ m) Al2024 composite. These phases contributed to the enhancement of the properties of both the Al7075 alloy and its composites. The developed composites can be used in automobile parts and aerospace applications.

AbstractFiber-reinforced polymer (FRP) composites undergo different environmental conditions in the designed life span. An investigation on aging of FRPs in water helps to enhance the material’s durability. This article aims to explore the effect of different types of water soaking (viz., tap, sea, and rain water) and re-drying conditions on the tensile and flexural strengths of glass fiber-epoxy composites (GFEC). The prepared specimens are placed in the sea, tap, and rain water for 10 weeks. Some specimens are re-dried at 50°C for 5 weeks. The water uptake (%) of seawater aged specimens decreases compared to tap and rain water-aged specimens at the end of 10 weeks. Water soaking of composites has reduced the tensile and flexural strengths of GFEC by 14 to 17%. The strength of water-soaked composite specimens is partly retrieved in specimens that have been re-dried. More than 90% of the original value is retrieved for the strength of GFECs (as-made specimens). SEM analysis of the tensile specimen fracture surface reveals the causes of the specimen failure as well as the impact of water soaking, followed with re-drying.

This technical paper presents the successful reinforcement of nickel (Ni) coated duralumin powder in an Al7075 matrix using the liquid stir casting technique and property stability obtained by heat treatment. Ni coating is performed by electroless nickel plating technique where 8 pm coating thickness was observed to be the minimum required to prevent dissolution of the reinforcements (duralumin powder) in the matrix (Al7075). During stir casting it was observed to uniformly disperse the coated duralumin powder up to 7 wt.%. Al7075 alloy and composites were artificially aged with solution heat treatment (SHT) performed at 450 & DEG;C for 4 h, water quenched and then aged at 120, 150 and 180 & DEG;C. Al7075 alloy and composites were naturally aged for 24 weeks in atmospheric temperature after peak aging. Composites aged at 120 & DEG;C exhibited superior results and considered as optimum aging temperature compared to those aged at 150 and 180 & DEG;C. Peak hardness values in 7075-7Dp+8T composite improved by 108% and 7075-7Dp+10T composite improved by 110% when compared to peak aged (at 120 & DEG;C) Al7075 alloy. Moreover, composites with coated reinforcement displayed a higher resistance to natural aging, with reductions of 53.5 and 54.4% in natural aging tendency compared to the naturally aged Al7075 alloy for 7075-7Dp+8T and 7075-7Dp+10T composites respectively. However, an increase in Ni coating thickness beyond the optimal 8 pm did not significantly improve as cast and peak hardness or natural aging resistance. XRD analysis confirmed that there is presence of CuAl2, CuAl2Mg, Mg2Si, and MgZn2 phases in peak-aged (120 & DEG;C) 7075-7Dp+8T sample. Considering the limited impact on property enhancement and the financial burden associated with thicker coatings, a coating thickness of 8 pm is recommended as compared to 10 pm.& COPY; 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

The work aims to prepare and characterize polyester nanoclay nanocomposite (PNNCs) with various nanoclay weight percentages (0, 2, and 4). Nanoclay and polyester resin are blended using a mechanical stirrer followed by a sonicator. The blend is molded as specimens as per ASTM standards. The addition of nanoclay improved tensile strength by 12% to 16% and flexural strength by 4% to 10%. After 60 days of soaking in, the tensile strength retention rate of pure PE, 2PNNC, and 4PNNC are 84.9%, 89.8%, and 90.6%, respectively. At the same time, flexural strength retention rates of pure PE, 2PNNC, and 4PNNC are 86.7%, 90.2%, and 91.9%, respectively. SEM images are analyzed to know the reasons for specimen failure under tensile load. ExpDec1 ("One-phase exponential decay function with time constant parameter") model is used on the experimental data to determine the composite's durability. The experimental values and data produced by the ExpDec1 model are relatively close to one another. In all specimens, the error percentage of experimental and predicted values during 80 and 100 days of water soaking varies very little (less than 1%). The study proposes CS-ANN (Cuckoo Search-Artificial Neural Network) architecture to predict mass loss. Test results prove that the CS-ANN predicted values are much closer to the experimental results. Cuckoo Search Algorithm (CSA) is used along with the ANN model to optimize and fine-tune the hyperparameters according to the data. The loss curves substantially prove the proposed model to be the best fit for the experimental data.

In the present work, the mechanical and morphological characterization of bamboo-glass fiber-nanoclay epoxy hybrid composites is carried out. Materials are prepared using a hand lay-up process with different wt.% of bamboo fiber, glass fiber, nanoclay, and epoxy. As per ASTM standards, fabricated composite laminates are cut and tested for tensile and flexural properties. The bamboo fiber epoxy composites (BFEC) display the tensile and flexural strength of 137 and 170 MPa, respectively. Hybrid composites, viz. bamboo-glass fibers epoxy composites (BGFEC), display improved tensile (180-240 MPa) and flexural (225 to 320 MPa) strengths compared to BFECs. Glass fiber epoxy composites (GFEC) display maximum tensile (265 MPa) and flexural (360 MPa) strengths among all the composites. Furthermore, the addition of nanoclay improves the tensile (by 6 to 8%) and flexural (by 8 to 10%) strengths of epoxy, BFEC, BGFEC, and GFECs. SEM analysis is conducted for fractured tensile specimens to understand the reasons for specimen failure.

The present work focuses on the effect of multistage solution heat treatment (MSHT) and artificial aging on two-stage stir-cast LM4 + TiB2 (1, 2, and 3 wt.%) composites on the mechanical properties as compared to as-cast and single-stage solution heat-treated (SSHT) composites. Two novel tests, viz. the confirmation hardness test and the chemical analysis test, were performed to ensure the soundness of the casting and uniform distribution of TiB2 within the matrix. Samples subjected to MSHT + aging at 100–200 °C displayed the highest hardness and UTS values compared to as-cast and SSHT + aging at 100–200 °C samples. Compared to as-cast alloy, peak-aged samples of 1–3 wt.% (MSHT + aging at 100 °C), hardness values improved from 107–150%, and UTS values improved from 47–68%. The presence of metastable phases (θ′-Al2Cu and θ″-Al3Cu) and of hard TiB2 particles are the reason for the improvement in the properties. Peak aged LM4 + 3 wt.% TiB2 composite displayed the highest hardness of 175 VHN and UTS of 251 MPa. Fracture analysis of the LM4 alloy showed dimple rupture, and its composites revealed quasi-cleavage fracture. Based on the overall results, the inclusion of TiB2, MSHT, and artificial aging treatment on the LM4 alloy significantly influenced the composites’ mechanical properties.