Matrix Composites Research Articles

Investigation and Characterization of Novel Aluminium Matrix Composites Enhanced by Recycled Borosilicate Glass

Investigation and Characterization of Novel Aluminium Matrix Composites Enhanced by Recycled Borosilicate Glass

Investigation of the microstructure, electrical and mechanical properties of Al-CNTs-B4C composite prepared by double-step stir casting for power transmission conductor

Abstract Monolithic aluminium alloy is a modern engineering material that is in high demand owing to its excellent performance and versatility. It has a high electrical conductivity, low density, high strength- to- weight ratio, and high resistance to corrosion. However, it lacks adequate resistance to creep, fatigue, stable microstructure, and strength at elevated temperatures. To overcome these deficiencies, aluminium matrix composites are developed. This work focuses on an experimental investigation of the microstructure, mechanical strength, and electrical conductivity of Al-CNTs-B4C composite consolidated by a double-step stir casting technique. An x-ray diffractometer, transmission electron microscopy, and a field-emission scanning electron microscope fitted with energy dispersive x-ray spectroscopy were used to characterize the start-up powders and the cast samples. A Brinell tester was used to measure the microhardness of the cast samples. A four-point probe meter was used to determine the electrical conductivity. The microstructural results revealed formation of Al4C3 and Al3BC intermetallics, B4C phase and amorphous carbon precipitate. Marginally improved electrical conductivity of 33.33 × 107 S m−1 (65.1% IACS) was obtained with Al-5CNTs-15B4C, together with high microhardness of 725.72 MPa. The microhardness improved by 94.7% over monolithic pure Al. The double-step stir casting enhanced the homogenous dispersion of the reinforcements. The improvements in the mechanical properties and electrical conductivity were attributed to the synergy between B4C and CNTs which induced Orowan looping, load transfer effect, plastic deformation and dislocation pinning in the composite. It is recommended that this composite will perform creditably in power transmission.

Effect of active powder addition on the mechanical properties of TiCp/manganese steel matrix composites

Abstract Different active powders were incorporated into TiC particle (TiCp) preforms of TiCp/manganese steel matrix composites to enhance the TiC/steel interfacial bonding. The effect of the active powders on bending strength and toughness of the composites was investgated. The composites were fabricated using a squeeze casting infiltration method, with a TiCp volume fraction of 50%. The active powders were mixed powders of Fe and tungsten carbide (WC), Ni and WC, and Ni and Si, respectively. Energy dispersive spectrometer (EDS) and transmission electron microscopy (TEM) were employed to analyze the interfacial microstructure of the composites. The results show that the addition of WCp results in the formation of a (W, Ti)C layer around TiCps, thereby strengthening the interfacial bonding. Conversely, the addition of Fe powder leads to the presence of significant glass-phase material at the interface, which is prone to cracking. Consequently, the composite with active Ni+WC exhibits notably higher bending strength (680.3 MPa) and impact toughness (7.7 J cm−2) compared to the composite with active Fe+WC (574.3 MPa and 2.6 J cm−2), with increases of 18.5% and 196.2%, respectively. Furthermore, the composite with active Ni+Si demonstrates the highest bending strength (886.7 MPa) and good toughness (4.3 J cm−2), which are 54.4% and 65.4% higher than those of the Fe+WC active composite, respectively, and its strength is 30.3% greater than that of the Ni+WC active composite. This improvement is attributed to enhanced wettability between TiCp and the matrix.

A Review on High-Performance SiCf/SiC Composites Prepared by PIP Process

Silicon carbide fiber-reinforced silicon carbide ceramic matrix composites (SiCf/SiC) are considered as a promising material for aero-engine hot-end structural components. The polymer infiltration and pyrolysis (PIP) process offers the benefits of high cost-effectiveness, adjustable preparation temperatures, and the ability to fabricate components with complex shapes. The manufacture of high-performance SiCf/SiC composites using the PIP process has become a research focus. This review briefly generalizes the synthesis methods of polycarbosilane and the specific process of polycarbosilane converting into SiC ceramics during pyrolysis. In addition, the physical and mechanical properties of SiCf/SiC composites prepared by the PIP process in recent years are discussed. Furthermore, this review summarizes some improvements to address the shortcomings of the PIP process, including adding fillers and combining other processes to assist the PIP process. At last, the future development trend of high-performance SiCf/SiC composites prepared by the PIP process is prospected.

High-entropy engineering improved the corrosion resistance of rare earth tantalates

High-entropy RETa3O9 ceramics have garnered significant interest in materials science due to their impressive high melting points and lower thermal conductivity. This study focuses on three types of these ceramics: (La0.2Ce0.2Nd0.2Sm0.2Dy0.2)Ta3O9, (La0.2Ce0.2Nd0.2Sm0.2Tm0.2)Ta3O9, and SmTa3O9.The results indicate that the coefficient of thermal expansion (TEC) for RETa3O9 ceramics remains in the range of approximately 5.94×10-6 K-1 to 6.05×10-6 K-1 when subjected to temperatures from room temperature up to 1400°C. This TEC is notably similar to that of silicon carbide ceramic matrix composites (SiC-CMC), which is essential for compatibility in applications where these materials are used together.Moreover, the study highlights an important finding: after 20 hours of exposure to a CMAS (calcium-magnesium-alumino-silicate) environment at 1300°C, the high-entropy tantalates exhibit significantly reduced susceptibility to corrosion compared to traditional single-component tantalate ceramics. While single-component materials, including SmTa3O9, showed greater degradation, the high-entropy RETa3O9 ceramics maintained their original morphology, free from porosity and cracking.This impressive resistance to CMAS corrosion indicates that the high-entropy design is beneficial in enhancing the durability of tantalates in extreme environments. Consequently, these findings suggest that high-entropy RETa3O9 ceramics hold promise for use as thermal/environmental barrier coating (T/EBC) materials in applications involving SiC-CMCs, potentially leading to improved performance and longevity in high-temperature applications.

Silica Particulate Dispersion during Additive Friction Deposition in a Metal Matrix Composite

This work presents a study of a low-power, solid-state additive manufacturing process to simultaneously mix and build a metal matrix composite. Specifically, an Al 6061 powder was blended with 11 wt.% silica (SiO2) after which the powders were solid-state consolidated through additive friction stir deposition (AFSD). The inclusion of the SiO2 resulted in an average hardness of 70 ± 1 HV as compared to a control (no SiO2) of 52 ± 1 Hv. However, for the SiO2 composite, the hardness varied in both the radial build and vertical build directions, with the highest hardness found in the centerline of the deposit. This inhomogeneity has been contributed to differences in how the SiO2 particulates evolve during the stirring and mixing processes of AFSD. Furthermore, this variation in particulate evolution was found to be a useful marker in understanding the microstructure evolution through AFSD.

Poly(Vinylidene Fluoride‐Hexafluoropropylene) Composites With Carbon Based Nanofillers for Electromagnetic Interference Shielding

ABSTRACTIn the current work, a series of flexible polymer matrix composites (PMCs) based on poly(vinylidene fluoride‐hexafluoropropylene) (PVDF‐HFP) as the polymer matrix and carbon nanofillers, namely single‐walled nanotubes (SWCNT) or carbon blacks (CB), were fabricated via a facile preparation method of blending and solution casting. The electrical conductivity, morphology, dielectric constant, mechanics, and electromagnetic interference (EMI) shielding properties of the composite films were adjusted by varying the carbon type (CB = Ketjenblack, Vulcan, or SWCNT = Tuball) and amount (0.1–15 wt%). The influence of the conductive nanofillers on the EMI shielding effectiveness (SE) and microwave absorbing properties in the X‐band frequency range (8–12 GHz) were investigated. By increasing the carbon content, the EMI shielding properties of the composite films were improved due to an increase in the magnitude of the electromagnetic properties. As the loading of these carbon fillers approach the percolation threshold, the dielectric constant of the composite can dramatically increase because of the construction of a microcapacitor network. However, these nanofillers/polymer composites generally have high dielectric loss near the percolation threshold due to the direct connection between carbon nanofillers. The PVDF‐HFP/Tuball composite particularly contributed low dielectric loss to the electromagnetic (EM) wave, resulting in excellent microwave absorption properties with a SE per unit thickness of 337.5 dB/mm and 2.5× less weight compared with conventional aluminum with the same SE, demonstrating the promise of using these materials as practical EMI shields.

Fabrication and characterization of SiC-reinforced magnesium-matrix composites with honeycomb structures and anisotropic properties

This study presents a novel approach for fabricating SiC-reinforced magnesium matrix composites by combining digital light processing (DLP) with pressureless infiltration. Pre-oxidation of SiC powder enhanced its wettability with the magnesium alloy, enabling the near-net-shape fabrication of honeycomb Mg-based composites with precisely controlled SiC and Al2O3 powder ratios. The influence of varying ceramic content on the microstructure and compressive properties of the composites was investigated, revealing significant mechanical anisotropy. A combined approach utilizing fracture morphology analysis and finite element simulations elucidated the compressive behavior and failure mechanisms of the composites under different loading directions. This work not only offers a promising route for on-demand design and fabrication of Mg-based composites but also provides valuable insights into understanding the mechanical behavior of architected composites.

Structural design of a polymer matrix composite ship propeller

This work presents the structural design of a propeller, with its profile established using the OpenProp software for a 5 m long competition catamaran at a speed of 5.5 m/s. The materials selected using the Ashby method were polymer matrix composites, and the chosen manufacturing method was vacuum bagging. The determination of the stacking sequence was initially done using panel theory and the macromechanics of composite materials. The stacking sequence was then optimized using the finite element method with Abaqus CAE. Experimental validation was conducted through instrumented cantilever bending tests on both specimens and the blade. The finite element results showed errors of less than 5% compared to the experimental measurements, thus validating the simulations and allowing the blade to be designed with static safety factors greater than eight under operational service conditions.

Combined hybrid machining of laser ablation-drilling small holes in Cf/SiC composites

Carbon fiber-reinforced silicon carbide composite material (Cf/SiC) serves as a typical advanced material for fabricating hot-end components of aircraft engines. Its unique properties, including high hardness and anisotropy, pose significant challenges in processing. Nevertheless, a crucial structural element of hot-end components, specifically the cooling and heat dissipation holes, necessitates hole machining within the Cf/SiC composites. The intricate nature of machining this material often leads to compromised surface quality and severe wear on cutting tools during the hole machining process. This study delves into the feasibility of combined hybrid machining of laser ablation-drilling(L-DCM) for fabricating small holes in woven Cf/SiC composites, along with elucidating the underlying material removal mechanisms. The findings reveal approach significantly enhances the cutting performance of hard alloys tools when dealing with ceramic matrix composites. Notably, the wear mechanisms of the cutting tools primarily involve abrasive wear and adhesive wear. The primary processing defects observed in the small holes include fiber pullout at the entrance and exit, as well as material delamination at the exit, which are primarily attributed to debonding at the layer interface and brittle fracture of the matrix. The subsequent drilling process, conducted based on laser drilling, effectively eliminates thermal defects such as the heat-affected zone and recast layer, as well as morphological defects like taper. Additionally, this approach mitigates the tool wear process, minimizes the impact of compression effects on material removal, and enhances the shear action of the tool. Consequently, the layer interface remains securely bonded and intact after processing, thereby preserving the material's strength.

Investigation of neuro-regenerative therapeutic potential of nerve composite matrix hydrogels embedded with adipose-derived stem cells

Investigation of neuro-regenerative therapeutic potential of nerve composite matrix hydrogels embedded with adipose-derived stem cells

EVALUATION OF PHYSICAL AND MECHANICAL PROPERTIES OF BN REINFORCED AL7079 METAL MATRIX COMPOSITES

Metal matrix composites (MMCs) are regarded as viable alternatives to conventional materials such as metals, plastics, and ceramics in structural applications due to their properties, including lightweight, high specific stiffness, elevated elastic modulus, enhanced specific strength, and excellent wear resistance. Among the many metal composites, aluminum metal matrix composites (MMCs) have emerged as sophisticated engineering materials for several prospective applications in engineering industries due to their superior qualities compared to typical aluminum alloys. Ceramic particles are the most extensively utilized reinforcements in MMCs due to their superior wear resistance, thermal stability, and exceptional bonding with the matrix. This research work has been conducted to develop ceramic particle-reinforced aluminum matrix composites and to evaluate their physical and mechanical properties. Al7079 alloy and Boron Nitride (BN) are selected as the matrix and reinforcement for the study respectively. The stir casting technique was utilized to fabricate the composites.Al7079-BN composites are prepared by varying the percentage of BN reinforcement particles from 0 to 8% by volume, with an increment of 2%. Test specimens were machined from the produced composites for the evaluation of microstructural, physical, mechanical properties according to ASTM standards. The microstructural analysis of the produced samples was conducted using scanning electron microscopy (SEM). The density of the composite was assessed empirically using Archimedes principle and theoretically through the rule of mixture. Microstructural analysis reveals a homogeneous distribution of BN particles throughout the matrix without any agglomeration, and it also demonstrates excellent bonding. The density of the composites decreased by approximately 4.6% with the incorporation of BN reinforcement up to 8%, attributed to the lower density of BN particles. The mechanical properties such as hardness, tensile strength, Youngs modulus, and compressive strength of the composite increases significantly.

Efficacy of jute-glass hybrid laminate composite wrapping under flexural loading

The demand for sustainable engineering materials has catalyzed interest in hybrid composites that combine natural fibers like jute with synthetic fibers such as E-glass. This study investigates the flexural strength of jute/E-glass/epoxy hybrid composite laminates under different stacking sequences, employing the ANOVA method to analyze their mechanical performance. The materials, including jute fabric, E-glass fabric, and epoxy resin, were arranged in various configurations and tested for flexural strength following ASTM D790 standards. The results indicated significant variability, with the GJGJ configuration exhibiting the highest average flexural strength of 71.20 MPa, while the GJG configuration had the lowest at 26.33 MPa. The ANOVA analysis confirmed a statistically significant effect of laminate configuration on flexural strength (F = 6.41, p = 0.004). These findings underscore the critical role of laminate arrangement in enhancing the mechanical properties of hybrid composites. The superior performance of the GJGJ configuration suggests that alternating layers of jute and E-glass fibers can effectively distribute stress and enhance load-bearing capacity. Conversely, suboptimal configurations like GJG demonstrated lower performance, highlighting the importance of strategic fiber arrangement. This research contributes to the development of optimized hybrid composites for various engineering applications, providing valuable insights into the interplay between natural and synthetic fibers within a composite matrix. The study's conclusions support the broader use of hybrid composites in industries such as automotive, construction, and aerospace, where material sustainability and performance are paramount. Future research should explore further optimization of stacking sequences and volume fractions of fibers, as well as investigate other mechanical properties such as tensile and impact strength, to fully realize the potential of hybrid composites in advanced engineering applications

Controls on coastal bluff erosion of a drowned drumlin field: Boston Harbor, Massachusetts

Eroding coastal bluffs pose significant risks to coastal communities, and an improved understanding of their erosional processes and mechanisms is essential for developing effective management strategies. The Boston Harbor Islands comprise more than two dozen drowned drumlins that were formed during the late-Pleistocene, many of which are now connected by spits. Exposed bluffs on the islands experience erosion due to waves and precipitation and are increasingly threatened by accelerating sea-level rise (SLR). Retreat rates for 31 bluffs along the drumlin shore, derived from orthoimagery (1995–2021) using the Digital Shoreline Analysis System add-in for ArcMap 10.8, range from 0.0 m/yr to 1.5 m/yr. These rates were examined in relation to several factors, including shoreline orientation, significant wave height during extratropical storms, till matrix composition, base elevation, bluff height, and presence of engineering structures. Clusters of bluffs with similar characteristics were identified, suggesting that high retreat rates coincide with bluffs that experience high wave energy, face the northeast and have high sand-to-mud ratios. The complexity of the Boston Harbor drumlin field and the variability of individual factors controlling erosion highlights the impracticality of developing a universal statistical model for predicting erosion rates. Rather a more suitable approach involves assessing trends among clusters of bluffs with similar characteristics. A similar approach can be taken for exploring the variability in retreat rates along other coastlines with complex or irregular bluff systems and wave fields.

A mean field homogenization model for the mechanical response of ceramic matrix composites

SiC/SiC composites offer exceptional mechanical stability at high temperatures and under irradiation. These ceramic matrix composites are therefore strong candidate materials for future nuclear energy applications. Their mechanical response, which exhibits pseudo-plasticity, is mediated by matrix cracking, fiber debonding, and fiber pull-out due to slip. This study introduces a mechanistic model for the behavior of unidirectionally reinforced SiC/SiC composites. Specifically a mean field homogenization approach is proposed to account for all deformation and degradation modes during mechanical deformation. The homogenization scheme relies on a Mori Tanaka method that is extended to consider the effects of the coating’s elasto-plastic response on the development of micromechanical fields. Further, the model proposed introduces a method to effectively account for the role of localized damage (i.e., cracks) on mechanical fields within both the fiber and the matrix. Upon validating the model against experimental data, the roles of interface sliding, coating dimensions and intrinsic elastic response, as well as of microstructure (e.g. porosity, fiber volume fraction) are discussed.

Fabrication of Aluminium Matrix Composite Powder Reinforced with Silicon Dioxide Tailings for Non-Asbestos Brake Pads (NOB)

Tin mining tailings consist of 80-90% sand and the rest mud. The high levels of Silicon Dioxide (SiO2) in these tailings are hard and can be used as an added material in the manufacture of composites. This research aims to study the physical and mechanical properties of metal matrix composites reinforced with SiO2 powder processed by powder metallurgy, as an effort to provide a replacement material for Non-Asbestos (NOB) motorbike brake linings. The impact of hot compaction pressure in the form of two pressing directions, including 4600, 4500 and 4400 Psi, with a pressing hold of 15 minutes and sintering which includes 30, 20 and 10 minutes, at a temperature of 600 ºC was studied for its effect on hardness and density. Mechanical blending was used with a horizontal ball mill in the ratio of 10:1 at a speed of 90 rpm for 4 hours. The test results showed that the greater the hot compaction pressure and the longer the sintering, the higher the hardness and density values. The highest hardness reached 81.7 HB and the highest density of 2.385 g/cm3 occurred at a bidirectional hot compaction pressure of 4600 Psi, with the lowest wear rate of 0.333 mm3/m. This occurs as a result of the increase in hot compaction has an impact on increasing the contact between powder particles resulting from mechanical alloying to be tighter as a result of which the cavity and porosity decrease

Effect of Alumina as Reinforcement on the Mechanical and Physical Properties of Recycled AA6061 Aluminium

The utilisation of reinforcement materials in aluminium metal matrix composites is widely used in the manufacturing sector due to their lightweight nature, excellent strength-to-weight ratio, enhanced fracture toughness, and improved mechanical properties. The purpose of this study is to investigate the effect of reinforcing alumina in recycled AA6061 aluminium on the properties of the resulting aluminium matrix composite. Various compositions of recycled AA6061 aluminium reinforced with alumina were prepared and analysed using the cold compaction method. The results show that the addition of alumina composition increases the hardness properties of the composite by up to 5 wt.% at 32.91 Hv compared to the unreinforced sample at 30.63 Hv, but the hardness decreases as the alumina mass composition increases. According to the analysis of physical properties, in comparison to the unreinforced sample, the density decreases with increasing mass composition of alumina up to 10 wt.%, which is from 2.4636 g/cm3 to 2.3014 g/cm3, respectively. In relation to the microstructure of the samples, the addition of alumina results in irregular shapes with larger pores. An increasing in the mass composition of alumina results in increased porosity and water absorption.

Reduced order modeling of turbulent reacting flows on low-rank matrix manifolds

A new low-rank approximation, referred to as time-dependent principal component analysis (t-PCA), is developed for reduced-order modeling (ROM) of scalar transport in turbulent reactive flows. In t-PCA, the evolution of the composition matrix is constrained to a low-rank matrix manifold, similar to that in standard PCA. Specifically, the t-PCA approximates the composition matrix through the multiplication of two thin, time-dependent matrices that represent spatial and composition subspaces. The evolution equations for these subspaces are derived by projecting the composition transport equation onto the tangent space of the low-rank matrix manifold. While the evolution equations for the spatial subspace in both PCA and t-PCA are similar, there are differences in how the composition subspace is obtained: (i) In t-PCA, the composition subspace is time-dependent, whereas in PCA, it is static. (ii) The t-PCA does not require any prior data, and an evolution equation for the composition subspace is derived. In PCA, the composition subspace is obtained from data. The t-PCA can be regarded as an on-the-fly low-rank approximation that can adapt to changes in the flow instantaneously. It is shown that the low-rank t-PCA approximations achieve residual levels lower than those obtained via PCA. For demonstrations and a comparative assessment of the ROMs, simulations are conducted of a non-premixed CO/H2 flame in a temporally evolving jet. Two cases are considered, based on the mechanisms previously suggested for combustion kinetics of this flame: (i) the GRI-Mech 3.0 model involving 53 species for a two-dimensional flame, (ii) the skeletal syngas model involving 11 species for a three-dimensional turbulent flame. The results are appraised via a posteriori comparisons against data generated via full-rank direct numerical simulation (DNS) of the same flame, and also with the PCA-reduced data from the DNS. It is shown that t-PCA yields excellent predictions of various features of the thermo-chemistry field.

Aluminum boron carbide metal matrix composites for fatigue-based applications: A comprehensive review

Metal matrix composites (MMCs), known for their low density and superior stiffness, have gained significant attention in various load bearing and fatigue-prone applications. These composites offer distinct advantages over traditional monolithic metals, including enhanced mechanical and tribological properties, making them prime candidates for lightweight structural applications. Among ceramic reinforcements, boron carbide stands out due to its lower density, high elastic modulus, excellent refractoriness, and superior hardness, positioning it as an ideal reinforcement material. This review delves into the processing techniques, material properties, and microstructural characteristics of boron carbide-reinforced MMCs, with a focus on aluminum LM6 alloy as the matrix. Additionally, the paper explores the latest advancements and emerging opportunities for employing these composites in fatigue-critical applications, highlighting their potential to revolutionize industries requiring high performance and durability under repeated loading conditions.

Aluminum matrix composites reinforced with high-entropy oxides and in situ formed Al2O3 and intermetallic compounds through aluminothermic reactions during spark plasma sintering

This work proposes a new strategy for producing aluminum matrix composites with strong interfaces by forming additional reinforcing particles in situ through an aluminothermic reaction between the system components. Sol-gel synthesized high-entropy spinel-type (Cr0.23Mn0.22Fe0.22Co0.19Ni0.13)3O4 oxides (HEO) were added to Al nanopowder and the resulting mixture was subjected to high-energy ball milling (HEBM) and then spark plasma sintering (SPS). As a result of the aluminothermic reaction during SPS, HEO are partially reduced, providing excess oxygen for the formation of reinforcing Al2O3 nanoparticles, and the reduced metals react with Al with the formation of various intermetallic compounds (Al9Me2, Al5Me2, and Al2Me), which, in addition to HEO, serve as secondary strengthening phases. A new hexagonal AlMex phase with lattice parameters of approximately a = c = 1.76 nm has been well documented. HEBM has been shown to be an important step not only for uniform HEO distribution, but also for the aluminothermic reaction to occur at a relatively low temperature by improving the interaction between activated Al and HEO nanopowders. The maximum increase in hardness with the addition of HEO is 198 %, tensile strength 90 % (25°C) and 97 % (500°C), and compressive strength 220 % (25°C) and 250 % (500°C). Excellent mechanical properties are achieved at 500°C: the ultimate tensile and compressive strength are 258 MPa and 410 MPa, respectively. The introduction of HEO also leads to a significant reduction in the coefficient of friction (from 0.7 (0 %) to 0.2 (3 %HEO)) and a noticeable reduction in dynamic wear (5.9–6.3 (3 %HEO) and 10.6–14.3 (5 %HEO) times depending on applied load). Thus, our research opens up exciting new possibilities for creating lightweight and high strength composites for use in the mid-temperature range.