Optimizing Mechanical Properties of Magnesium Matrix Composites via Stir Casting for Automobile Applications

The application of natural fibers is increasing rapidly in the polymer-based composites. This study investigates manufacturing and characterization of polypropylene (PP) based composites reinforced with three different natural fibers: jute, kenaf, and pineapple leaf fiber (PALF). In each case, the fiber weight percentages were varied by 30 wt.%, 35 wt.%, and 40 wt.%. Mechanical properties such as tensile, flexural, and impact strengths were determined by following the relevant standards. Fourier transform infrared (FTIR) spectroscopy was employed to identify the chemical interactions between the fiber and the PP matrix material. Tensile strength and Izod impact strength of the composites significantly increased for all the composites with different fiber contents when compared to the pure PP matrix. The tensile moduli of the composites were compared to the values obtained from two theoretical models based on the modified "rule of mixtures" method. Results from the modelling agreed well with the experimental results. Tensile strength (ranging from 43 to 58 MPa), flexural strength (ranging from 53 to 67 MPa), and impact strength (ranging from 25 to 46 kJ/m2) of the composites significantly increased for all the composites with different fiber contents when compared to the pure PP matrix having tensile strength of 36 MPa, flexural strength of 53 Mpa, and impact strength of 22 kJ/m2. Furthermore, an improvement in flexural strength but not highly significant was found for majority of the composites. Overall, PALF-PP displayed better mechanical properties among the composites due to the high tensile strength of PALF. In most of the cases, T98 (degradation temperature at 98% weight loss) of the composite samples was higher (532-544 °C) than that of 100% PP (500 °C) matrix. Fractured surfaces of the composites were observed in a scanning electron microscope (SEM) and analyses were made in terms of fiber matrix interaction. This comparison will help the researcher to select any of the natural fiber for fiber-based reinforced composites according to the requirement of the final product.

Novel short Agave americana based biocomposite and nanobiocomposites for automotive applications

Although concrete is the most widely used construction material, its deficiency in shrinkage and low tensile resistance is undeniable. However, the aforementioned defects can be partially modified by addition of fibers. On the other hand, possibility of adding waste materials in concrete has provided a new ground for use of recycled concrete aggregates in the construction industry. In this study, a constant combination of recyclable coarse and fine concrete aggregates was used to replace the corresponding aggregates at 50% substitution percentage. Moreover, in order to investigate the effects of fibers on mechanical and durability properties of recycled aggregate concrete, the amounts of 0.5%, 1%, and 1.5% steel fibers (ST) and 0.05%, 0.1% and 0.15% polypropylene (PP) fibers by volumes were used individually and in hybrid forms. Compressive strength, tensile strength, flexural strength, ultrasonic pulse velocity (UPV), water absorption, toughness, elastic modulus and shrinkage of samples were investigated. The results of mechanical properties showed that PP fibers reduced the compressive strength while positive impact of steel fibers was evident both in single and hybrid forms. Tensile and flexural strength of samples were improved and the energy absorption of samples containing fibers increased substantially before and after crack presence. Growth in toughness especially in hybrid fiber-reinforced specimens retarded the propagation of cracks. Modulus of elasticity was decreased by the addition of PP fibers while the contrary trend was observed with the addition of steel fibers. PP fibers decreased the ultrasonic pulse velocity slightly and had undesirable effect on water absorption. However, steel fiber caused negligible decline in UPV and a small impact on water absorption. Steel fibers reduce the drying shrinkage by up to 35% when was applied solely. Using fibers also resulted in increasing the ductility of samples in failure. In addition, mechanical properties changes were also evaluated by statistical analysis of MATLAB software and smoothing spline interpolation on compressive, flexural, and indirect tensile strength. Using shell interpolation, the optimization process in areas without laboratory results led to determining optimal theoretical points in a two-parameter system including steel fibers and polypropylene.

In this study, a facile hybridization of sisal/coconut palm reinforced epoxy composite, is presented. The fabrication method involved the use of hand lay‐up techniques. The results of the fabricated composites were investigated by using the universal testing machine, hardness testing machine, scanning electron microscope, and an impact testing machine. In order to obtain optimize results for the tensile, flexural, and impact strengths of the fabricated samples, the fabrication procedures involved varying the volume fractions of sisal and coconut palm hybrid with different compositions. The maximum tensile, flexural, and impact strengths measured for the fabricated fiber/polymer composite, are: 45 MPa, 90 MPa, and 38.9 kJ/m2. The scanning electron microscopy (SEM) and energy dispersive x‐ray spectrometry (EDS) of the composites showed that the composites with equal volume fractions of sisal and coconut palm fiber exhibited better performance and better mechanical properties. Furthermore, the improved mechanical properties such as hardness, tensile strength, flexural strength and impact strength were obtained with fibers of longer length. By considering the excellent mechanical properties of the fabricated composite, it is envisaged that the composite be suitable for the manufacturing of helmet, automobile and train coach interiors.

In the recent decades, magnesium matrix composites present a plenty of applications in automotive, marine and aerospace industries. In this work, AZ31B is selected as Mg matrix material and hard Tungsten carbide (WC) particles as reinforcement material. Mg/WC composites are reinforced with different weight proportions (0, 5, 10 and 15% wt.) using stir casting method. The worn surface of manufactured Mg/WC composites and base Mg material were examined by scanning electron microscope (SEM). The wear test results denote that AZ31B/15% wt. WC composites have excellent tribological behaviour when compared to the base magnesium matrix AZ31B alloy. The yield tensile strength, flexural strength, ultimate tensile strength and micro-hardness of the manufactured composites are improved by increasing the WC content. Further, SEM analysis revealed the homogeneous distribution of WC particles throughout the Mg matrix.

An overview of the effect of stirrer design on the mechanical properties of Aluminium Alloy Matrix Composites fabricated by stir casting

Pineapple fiber reinforced polyvinyl chloride (PVC) composites (25-75% fiber by weight) were fabricated using compression molding technique and the mechanical properties such as tensile strength (TS), tensile modulus (TM), bending strength (BS), bending modulus (BM) and impact strength (IS) of the composites were evaluated. It was found that at 55% fiber content, the composite exhibited the best mechanical properties. The TS, TM, BS, BM and IS were found to be 48.8 MPa, 773 MPa, 75.6 MPa, 4.2 GPa, 21.4 KJ/m2 for 55% fiber composite. The composites were exposed to different intensities of ultraviolet (UV) radiation (25-200 UV dose) and found significant improvement in the mechanical properties up to 100 UV dose. At 100 UV dose, the value of TS, TM, BS, BM and IS of the composite were found to be 57.3 MPa, 932 MPa, 87.5 MPa, 5.2 GPa and 26.3 KJ/m2 respectively. Water uptake behaviours of the non-irradiated and UV irradiated composites were also observed. The interfacial property was examined by scanning electron microscopy (SEM).

This research examines the mechanical properties of composites made from flax fiber and polyester resin. Hybrid composites were produced by integrating flax fiber, known for its exceptional tensile and flexural strengths, with graphene oxide nanoparticles (nGO) and polyester resin. The flexural and ultimate tensile strengths of the composites were predicted using a multilayer perceptron (MLP) regression model, a type of artificial neural network (ANN). The composite material FGO-1, comprising 40 wt.% flax fiber, 1 wt.% graphene oxide nanoparticles, and 59 wt.% polyester resin, exhibited outstanding mechanical properties. The FGO-1 sample showed improvements in flexural modulus (46.80%), flexural strength (50.80%), tensile modulus (32%), and tensile strength (37.83%). The energy absorption rate was 32.69%, and its impact resistance exceeded that of the other composite formulations by 8.75%. The ANN model successfully predicted these strengths, achieving R2 values of 0.89 and 0.98 for flexural and tensile strengths, respectively. Microstructural analysis using a scanning electron microscope (SEM) was conducted alongside tensile, flexural, impact, and interlaminar shear strength tests to evaluate the composite’s performance.

Magnesium matrix composite is one of the advanced lightweight materials with high potential to be used in automotive and aircraft industries due to its low density and high specific mechanical properties. The magnesium composites can be fabricated by adding the reinforcements of fibers or/and particles. In the previous literature, extensive studies have been performed on the development of matrix grain structure of aluminum-based metal matrix composites. However, there is limited information available on the development of grain structure during the solidification of particulate-reinforced magnesium. In this work, a 5 vol.% SiCp particulate-reinforced magnesium (AM50A) matrix composite (AM50A/SiCp) was prepared by stir casting. The solidification behavior of the cast AM50A/SiCp composite was investigated by computer-based thermal analysis. Optical and scanning electron microscopies (SEM) were employed to examine the occurrence of nucleation and grain refinement involved. The results indicate that the addition of SiCp particulates leads to a finer grain structure in the composite compared with the matrix alloy. The refinement of grain structure should be attributed to both the heterogeneous nucleation and the restricted primary crystal growth.

The purpose of this study is to evaluate the impact of different infill patterns on the mechanical and ballistic behaviour of 3D-printed carbon-nylon composites. The carbon nylon material was used to print samples with different infill patterns such as (Tri-Hexagon, Cubic, and Gyroid) and with an infill density of 80%. The mechanical tests such as tensile, flexural, impact, and interlaminar shear strength (ILSS) were examined on the printed samples. The results have shown that the gyroid pattern had shown better performance in mechanical characteristics. The mechanical characteristics of 3D printed samples with gyroid pattern showed improvements of 16.63% in tensile strength, 5.64% in flexural strength, 6.52% in impact strength, and 16.72% in ILSS respectively in contrast with tri-hexagon infill pattern. Micrograph evaluation was done on the damaged surfaces of tensile and flexural tested specimens. The microscopy image of the gyroid pattern’s fractured surface has revealed improved bonding, minimal voids, and no delamination, which may be the cause of the increase in mechanical properties. Besides, the micrograph image revealed that more voids in the cube pattern, are considered to be responsible for its lower mechanical performance. The high-velocity impact test was done to examine the energy absorption behaviour and damage propagation of 3D printed samples with an infill density of 80%. The findings revealed that the gyroid pattern improved their impact resistance. The ballistic impact test results show that the gyroid pattern affords better energy absorption because of its continuous structure, and efficiently disperses impact energy throughout the sample’s entire volume. The printed samples with the gyroid pattern showed a 5.24% rise in energy absorption than the cube pattern. The optimal infill density and infill pattern could be used to make materials for impact applications due to their better mechanical and energy absorption abilities.

Carbon fiber reinforced thermoplastic composites have such advantages as low density, high strength, high temperature resistance, impact resistance, and good ductility, but due to the density difference between carbon fibers and resin fibers, it is difficult to mix them uniformly. Hence, it is difficult to prepare the composites with the uniform properties. In order to solve this problem, a preparation process based on solid phase mixing of carbon and resin fibers by suspension method is proposed in this paper. The carbon fiber reinforced thermoplastic composites (CFRTPs) can be prepared by dispersing carbon fibers of a certain length (~50 mm) and resin fibers in suspension through ultrasound‐assisted and churn‐combing methods. The effects of carbon fiber length, content and molding process on the mechanical properties of the CFRTPs were studied. The results show that the carbon fiber content and length are the main factors affecting the mechanical properties as well as void ratio of CFRTP. The performance of composites is significantly improved with the increase of carbon fiber length. While the length of carbon fiber is 50 mm and the content is 30 wt%, the prepared CFRTP has the best performance, with the tensile strength of 182.1 MPa, the bending strength of 354.3 MPa, the impact strength of 67.2 KJ·m−2, and the material void ratio of 0.65%. The study shows that the suspension method is feasible for the preparation of the CFRTPs. It is beneficial to improve production efficiency and decrease cost of production for the CFRTPs.Highlights Carbon fiber reinforced thermoplastic composites can be prepared by dispersing carbon fibers of a certain length (~50 mm) and resin fibers in suspension through ultrasound‐assisted and churn‐combing methods. Through the cooling‐high pressure molding process, the porosity of CFRTP is reduced and the mechanical properties of CFRTP are improved. The tensile strength, bending strength, and notch‐free impact strength properties of CFRTP are best when the carbon fiber content is 30% and the CF length is 50 mm. The method is characterized by simple process, low cost and high mechanical properties.

Natural fibers are replacing synthetic fibers and are used to develop different useful composite products due to their environmental advantages. To fabricate high-performance composites, high-quality natural fibers are essential. Fiber quality largely depends on the extraction method and subsequent treatment. In this study, fibers were extracted using both machine and manual methods, treated with 5% NaOH, and used at a 30:70 fiber-to-matrix volume ratio to fabricate composite laminates. Key properties such as tensile, flexural, and impact strength, water absorption, elemental composition, and morphological structure were analyzed. When comparing the untreated fiber composites, the machine-extracted samples exhibited a 6.7% increase in tensile strength and a 7.06% increase in flexural strength over those extracted manually. For treated fiber composites, the machine-extracted samples showed improvements in tensile, flexural, and impact strengths of 19.82%, 19.38%, and 26.59%, respectively, compared to those extracted manually. These enhancements indicate that machine extraction provides fibers with better structural integrity and consistency, contributing to stronger fiber–matrix bonding. The machine-extracted treated composites showed reduced water absorption and smaller fiber diameters, indicating that machine extraction was more effective in removing impurities from the fibers. Scanning electron microscopy (SEM) confirmed improved fiber–matrix interfacial bonding in the machine-extracted composites, which also exhibited better water resistance. This study highlights that fiber extraction and treatment significantly influence the mechanical, physical, and morphological properties of natural fiber composites, as verified through SEM, EDS, and universal testing machine (UTM) analysis.

Innovative high-density polyethylene/waste glass powder composite with remarkable mechanical, thermal and recyclable properties for technical applications

Improvement of mechanical properties of jute-nano cellulose-reinforced unsaturated polyester resin-based composite: Effects of gamma radiation

Metal matrix composites are the resultant of combination of two or more elements or compounds, possessing enhanced characteristics than the individual constituents present in them. This paper deals with the fabrication of Al 2014-SiC composite and investigation of its Microstructure and Mechanical properties. 2014 Aluminium alloy is characterized by good hardness. It is selected as the base metal. The Silicon Carbide is characterized by good strength and low density (3.21 g/cm3). It is chosen as the reinforcement. Silicon Carbide is coated with Nickel by electroless method to increase its wettability and binding properties. The fabrication of metal matrix composites is done by stir casting in a furnace, by introducing the required quantities of reinforcement into molten Aluminium alloy. The reinforcement and alloy is mixed by means of stirring, with the help of a stirrer. The base alloy and the composites are then tested for mechanical properties such as tensile strength, flexural strength, impact strength and hardness. The fabricated samples have higher tensile strength and impact strength than the alloy. Microstructure of the samples, are analyzed using optical microscope.