Aluminum Matrix Composites Research Articles

Effect of Dynamic Recrystallization Mode on Texture Components and Hardness for Nano-SiC Particles Reinforced Aluminum Matrix Composites Prepared Via Friction Stir Processing

Effect of Dynamic Recrystallization Mode on Texture Components and Hardness for Nano-SiC Particles Reinforced Aluminum Matrix Composites Prepared Via Friction Stir Processing

Microstructural and nanoindentation study of spark plasma sintered high entropy alloy reinforced aluminium matrix composites

In this study, Spark Plasma Sintering (SPS) also known as a field-assisted technique was employed in the fabrication of high entropy alloy (HEA) reinforced aluminium matrix composites (using 5, 7 and 10 wt% HEA as the reinforcement in the composites); and conventional methods were employed to determine the relative density and microhardness; while nanoindentation technique was employed to determine the nanohardness, modulus of elasticity and nanoindentation depth of the sintered samples. Calculation Phase Diagram (CALPHAD) software, Thermocalc was employed in the prediction of the phases present in the HEA, while XRD was used in the confirmation of the phases. The phase analysis showed that BCC, FCC, and laves are the phases present in the fabricated HEA while the microstructural analysis showed that interdiffusion layers were formed; and atomic precipitation that resulted in the formation of new phases occurred during sintering. The microhardness, nanohardness, and modulus of elasticity of the sintered HEA-reinforced Al matrix composites increase with an increase in the wt% of HEA such that as little as 5 wt% HEA addition resulted in a 102.8 % increment in microhardness, while the densification and indentation depth were discovered to decrease with an increase in the wt% of HEA.”

Iron-Added Aluminum Matrix Composites Prepared by Friction Stir Processing: Structure, Mechanical and Tribological Properties

Iron-Added Aluminum Matrix Composites Prepared by Friction Stir Processing: Structure, Mechanical and Tribological Properties

Achieving Superior Strength–Ductility–Conductivity Combination in TiB2p/6201 Composites via Particle Rotation and Subgrain Refinement

The key factor in the material design of overhead power transmission lines is to obtain a desired balance among strength, ductility, and electrical conductivity. Herein, TiB2 particulate‐reinforced aluminum matrix composites are prepared to find a way out of the intrinsic dilemma behind this balance by tailoring the subgrain refinement. The interaction in the form of inhomogeneous deformation induced by the flexibility discrepancy between the rigid particles and soft matrix is studied. On the one hand, the hexagonal plate‐like TiB2 particles rotate with the inhomogeneous deformation, forcing the biggest exposed plane ((0001) basal plane) parallel to the plastic flow direction, which is beneficial for the dislocation multiplication and hindrance of dislocation slipping. On the other hand, inhomogeneous deformation generates plentiful geometry necessary dislocations and divides the microstructure into two types: in the particle‐rich region ultrafine grains are formed and in the particle‐free region significant subgrains refinement is observed. The subgrains with 3 wt% TiB2 are refined from ≈897 to ≈248 nm. Thanks to these microstructural benefits, the composites achieve the following strength–ductility–conductivity combination: ultimate tensile strength is 370 MPa, elongation after fracture is 11.2%, and electrical conductivity is 51.79% IACS. Besides, the elastic modulus reaches 75.43 GPa.

An experimental strategy and investigation of preparing high-strength and low-expansion carbon fiber reinforced Al matrix composite

In the pursuit of advancing the aerospace application of carbon fiber-reinforced aluminum matrix (CF/Al) composites, achieving a balance between strength, toughness, and a reduced coefficient of thermal expansion (CTE) is imperative. This research introduces a novel approach to fabricating a carbon fiber-reinforced titanium/aluminum (Ti-CF/Al-Ti) sandwich composite using a liquid-solid infiltration extrusion method. The microstructure, mechanical properties, thermal deformation, and corrosion resistance were thoroughly analysed. The results show that a 10 μm wide transition layer interface (Al3Ti) generated by Ti/Al interdiffusion is formed in the sandwich composite and forms an inlay structure with carbon fibers. Compared with CF/Al composites, the tensile strength of this sandwich composite was enhanced by 137.04% and 207.55% in the axial and radial directions of the fibers, respectively, while the compressive strength was also significantly increased. Notably, the CTE of the sandwich composite in the radial direction of the fibers was reduced by 51.2% after the introduction of the TC4, while the axial CTE remained unchanged. Additionally, the corrosion current density (icorr) exhibited a remarkable decrease by two orders of magnitude, indicating a substantial improvement in corrosion resistance. These findings provide valuable insights into the preparation of CF/Al composite and their applications in aerospace.

Effect of carbon nanotubes on mechanical properties of aluminum matrix composites: A review

Abstract Carbon nanotubes (CNTs) are renowned for their low density, high elastic modulus, and exceptional electrical and thermal properties. The continuously developing applications of CNTs provide higher specific stiffness and strength for composite materials. The unique characteristics of CNTs make them ideal reinforcing particles in aluminum matrix composites (AMMCs), which generally exhibit excellent mechanical properties. CNTs/AMMCs are usually prepared using methods such as powder metallurgy, casting, spray deposition, and reactive melting. The uniform diffusion of CNTs in composites is crucial for enhancing the properties of CNTs/AMMCs. The properties of CNTs/AMMCs largely depend on the content, morphology, and distribution of reinforcements in the matrix and the interaction between reinforcements and the matrix. By adding an appropriate volume fraction of CNTs, the hardness, tensile strength, compressive strength, and electrical properties of CNTs/AMMCs were significantly improved. The effects of CNT content on the mechanical properties of CNTs/AMMCs, including the tensile strength, yield strength, compressive strength, stress–strain curve behavior, elastic modulus, hardness, creep, and fatigue behavior, were revealed. The design of microstructure, optimization of the preparation process, and optimization of composition can further improve the mechanical properties of CNTs/AMMCs and expand their application in engineering. The design concept of integrating material homogenization and functional unit structure through biomimetic design of novel gradient structures, layered structures, and multi-level twin structures further optimizes the composition and microstructure of CNTs/AMMCs, which is the key to further obtaining high-performance CNTs/AMMCs. As a multifunctional composite material, CNTs/AMMCs have broad application prospects in fields such as air force, military, aerospace, automation, and electronics. Moreover, CNTs/AMMCs have potential applications in cell therapy, tissue engineering, and other areas.

Strength-Plasticity Relationship and Intragranular Nanophase Distribution of Hybrid (GNS + SiCnp)/Al Composites Based on Heat Treatment.

The distribution of reinforcements and interfacial bonding state with the metal matrix are crucial factors in achieving excellent comprehensive mechanical properties for aluminum (Al) matrix composites. Normally, after heat treatment, graphene nanosheets (GNSs)/Al composites experience a significant loss of strength. Here, better performance of GNS/Al was explored with a hybrid strategy by introducing 0.9 vol.% silicon carbide nanoparticles (SiCnp) into the composite. Pre-ball milling of Al powders and 0.9 vol.% SiCnp gained Al flakes that provided a large dispersion area for 3.0 vol.% GNS during the shift speed ball milling process, leading to uniformly dispersed GNS for both as-sintered and as-extruded (0.9 vol.% SiCnp + 3.0 vol.% GNS)/Al. High-temperature heat treatment at 600 °C for 60 min was performed on the as-extruded composite, giving rise to intragranular distribution of SiCnp due to recrystallization and grain growth of the Al matrix. Meanwhile, nanoscale Al4C3, which can act as an additional reinforcing nanoparticle, was generated because of an appropriate interfacial reaction between GNS and Al. The intragranular distribution of both nanoparticles improves the Al matrix continuity of composites and plays a key role in ensuring the plasticity of composites. As a result, the work hardening ability of the heat-treated hybrid (0.9 vol.% SiCnp + 3.0 vol.% GNS)/Al composite was well improved, and the tensile elongation increased by 42.7% with little loss of the strength. The present work provides a new strategy in achieving coordination on strength-plasticity of Al matrix composites.

Microstructure and tribological properties of aluminum matrix composites reinforced with ZnO–hBN nanocomposite particles

Abstract In this study, pure and hBN-doped ZnO nanoparticles were synthesized by sol–gel method. ZnO–hBN nanoparticles were mixed with pure aluminum powders and samples were prepared using powder metallurgy processing parameters. It was observed that Al, ZnO, and hBN nanocomposite particles formed homogeneously. With the addition of ZnO–hBN, significant changes occurred in hardness, wear, and friction coefficient values compared to pure Al samples. The highest hardness value in the samples is mesh. It was obtained as 105 HB in 10 wt.% hBN added sample. In the wear tests, it is seen that the wear resistance is seven times higher in the 1 wt.% hBN added sample compared to the pure Al sample, while the friction coefficient decreases with the increase of the hBN additive.

Nano-Enhanced Phase Reinforced Magnesium Matrix Composites: A Review of the Matrix, Reinforcement, Interface Design, Properties and Potential Applications.

Magnesium matrix composites are essential lightweight metal matrix composites, following aluminum matrix composites, with outstanding application prospects in automotive, aerospace lightweight and biomedical materials because of their high specific strength, low density and specific stiffness, good casting performance and rich resources. However, the inherent low plasticity and poor fatigue resistance of magnesium hamper its further application to a certain extent. Many researchers have tried many strengthening methods to improve the properties of magnesium alloys, while the relationship between wear resistance and plasticity still needs to be further improved. The nanoparticles added exhibit a good strengthening effect, especially the ceramic nanoparticles. Nanoparticle-reinforced magnesium matrix composites not only exhibit a high impact toughness, but also maintain the high strength and wear resistance of ceramic materials, effectively balancing the restriction between the strength and toughness. Therefore, this work aims to provide a review of the state of the art of research on the matrix, reinforcement, design, properties and potential applications of nano-reinforced phase-reinforced magnesium matrix composites (especially ceramic nanoparticle-reinforced ones). The conventional and potential matrices for the fabrication of magnesium matrix composites are introduced. The classification and influence of ceramic reinforcements are assessed, and the factors influencing interface bonding strength between reinforcements and matrix, regulation and design, performance and application are analyzed. Finally, the scope of future research in this field is discussed.

Achieving exceptional strength by multi-dimensional in-situ Al3Ti, TiN, AlN reinforcements in Al matrix composites

Despite the high demand for strong, lightweight, and tough Aluminum Matrix Composites (AMCs) across various applications, achieving desired property compatibility remains challenging due to limited control over the reinforcement processes. A novel AMC has been developed and synergistically reinforced with transgranular microscale Al3Ti, sub-microscale TiN, and intergranular nanoscale AlN, through Ti2AlN and Al in situ reaction. The in-situ multiphase-and-scale structure, resulting from the intricate reaction mechanisms and N interstitial solution, was analyzed using experimental investigations, thermodynamics and kinetics calculations, while the robust interfacial properties were studied by first-principles calculations. Both endowed the composite with exceptional strength (776 MPa and 635 MPa for compressive and flexural strength). Strengthen mechanisms were composed of fine-grain, solid-solution, and dislocation strengthening. This work succeeds in refining Al3Ti particles and creatively breaks through the bottleneck of synthesizing multi-dimensional and tunable in-situ reinforcements, expected to open new avenues for developing and applying a new generation of advanced AMCs.

Stir casting studies on aluminium (Al8011) and zirconia (ZrO2) metal matrix composites

This study investigates the properties of Aluminium (Al8011) and Zirconia (ZrO2) metal matrix composites (MMCs) fabricated through stir casting, which is a common technique used to produce MMCs. Al8011 was used as the matrix material whilst ZrO2, a ceramic material, was used as the reinforcement. The composites were developed with varying weight percentages of ZrO2 (4, 8 and 12 wt%) and were analysed using tensile, wear and hardness, scanning electron microscopy (SEM) and hardness testing. The findings show that as the percentage of ZrO2 increased in the composites, the density and hardness significantly increased. SEM results revealed that the distribution of ZrO2 was homogenous throughout the matrix, indicating the method of stirring was effective in improving particle dispersion. Overall, the study concluded that MMCs with high percentage of ZrO2 has the potential to enhance mechanical and physical properties whilst maintaining insignificant level of porosity. However, future research is needed to address the impurities identified in this study.

High-speed drilling mechanism study of unidirectional CoCrFeNiAl fiber-reinforced aluminum matrix composites

High-speed drilling mechanism study of unidirectional CoCrFeNiAl fiber-reinforced aluminum matrix composites

Selection of groove dimension in the fabrication of particulate reinforced aluminium matrix composites using friction stir welding

Selecting groove dimensions has always been challenging for fabricating particulate reinforced aluminium matrix composites using friction stir welding. To address this, heat transfer physics coupled with the level set method was used to estimate material mixing between 6061-T6 Al-matrix and Al2O3 using the COMSOL Multiphysics tool. Groove dimensions of 2 mm width and depth resulted in the absence of volumetric/tunnel defects, nearly symmetric distribution, and minimal agglomeration of Al2O3 powder particles. This combination achieved an optimum trade-off between strength and ductility.

The role of Mg content in regulating microstructures and mechanical properties of Al–Mg–ZnO composites fabricated via in-situ reaction sintering

Al–Mg-oxides composite system exhibits great potential for achieving aluminum matrix composites (AMCs) with exceptional mechanical properties. However, the effects of Mg element on in-situ reaction mechanism and precipitation behavior remains largely unknown. In this work, Al–Mg–ZnO composite was successfully fabricated by using segmented ball milling, reaction sintering and heat treatment, resulting in an ultimate tensile strength of ∼760 MPa and fracture elongation of ∼3.5 %. The Mg content-dependent reaction pathway and precipitation evolution were systematically investigated through thermodynamic analysis and microstructural characterization. The results revealed that the relatively high Mg content promotes the in-situ generation of the hybrid reinforcements composed of MgAl2O4 and MgO. Additionally, the semi-coherent reinforcement-matrix interface facilitates interfacial precipitation by reducing the energy barrier for nucleation. Consequently, solute-rich/vacancy-rich Guinier-Preston (GP) zones are activated to form η′ and T′ precipitates. These high-density nano-sized secondary phases contribute to the considerable strengthening effect of the composite. The present work provides valuable theoretical insight into the effect of Mg content on the microstructure evolution of Al–Mg–ZnO composite system, which offers promising avenues for achieving AMCs with superior mechanical properties.

Achieving the strength-ductility synergy in ultra-fined grained CNT/2024Al composites via a low-temperature aging strategy

Synchronous enhancement of strength and ductility is a persistent challenge in the development and application of carbon nanotube (CNT)-reinforced aluminum matrix composites. This study proposed a low-temperature aging strategy to induce the nanoscale precipitates and evade the strength and ductility trade-off dilemma. The composites under various aging conditions were characterized in detail at the macro, micro, and nano scales. The precipitation behavior and strengthening mechanism were investigated systematically. Results indicated that the composite exhibited a better mechanical performance when aged at 100 °C. Compared to as-extruded composites, the yield and ultimate tensile strength of CNT/2024Al composites increased by 82.7 % and 64.8 %, respectively, whereas the elongation decreased by only 1.1 %. The results of microstructure and theoretical estimation suggested the dense nanoscale GP zones were primarily responsible for achieving the strength-ductility synergy. This present study on tailoring precipitate evolution could provide fundamental insights and references to enhance the mechanical properties of aluminum matrix composites.

A facile treatment of graphite as a reinforcement for Al‐based nanostructured composite

Aluminum‐graphite composites find extensive applications in diverse industries, including automotive and aerospace sectors. However, the fabrication of these composites faces a significant challenge due to poor wettability and weak interfacial bonding between graphite and aluminum. This work aims to modify the graphite particles to improve the characteristics of aluminum. In this study, treated graphite (TG) was synthesized using a facile method for the first time. Graphite (G) was mixed with acetone and stirred with a mechanical stirrer at 2000 rpm for 1 h, followed by drying in an electric oven at 80°C for 1 h. Mechanical milling and subsequent hot pressing were employed to manufacture composites with 1, 3, and 5 wt.% of G and TG. The results demonstrated that the addition of G and TG up to 5 wt.% substantially improved the wear rate and coefficient of friction (COF). However, it also resulted in a deterioration of the mechanical properties of aluminum. The TG‐reinforced composites exhibited enhanced mechanical and tribological properties owing to the stronger bonds formed between carbon and aluminum atoms. Notably, the composite with 5‐wt.% G and TG exhibited an 80% and 58% lower COF compared with unreinforced aluminum. Composites containing 1‐wt.% G and TG showed an 11% and 1% reduction in yield strength, respectively. Consequently, the investigated graphite treatment proves to be an effective method for modifying the interfacial bonding and enhancing the comprehensive properties of aluminum. This treatment offers a simple and cost‐effective approach to improve the tribological and mechanical characteristics of aluminum matrix composites.

Microstructure and properties of 316 L lattice/Al composites by additive manufacturing and infiltration with different temperature

Interface between lattice reinforcement and matrix played a key factor on properties of the lattice reinforced aluminum matrix composites. However, the effect of interface composed of intermetallic compounds on the properties of 316 L lattice/Al composites was still unclear. In this study, 316 L lattice reinforced aluminum composite with continuous interface were prepared by combining laser powder bed fusion (LPBF) and vacuum infiltration, and effect of infiltration temperature on interface evolution and properties of the composite was investigated. Results indicated that a continuous dual-phase interfacial layer consisting of hard intermetallic compounds η-Fe2Al5 and θ-FeAl3 was formed between the reinforcement and matrix due to diffusion and reaction of iron and aluminum atoms, and the size of needle-type FeAl3 phase in the interfacial zone increased when infiltration temperature was up from 800 °C to 900 °C. It also confirmed that reinforced by 316 L lattice and hard intermetallic compounds layer, the composite showed excellent mechanical and wear resistant properties, with compressive strength of 657 ± 32 MPa and specific wear rate of 0.20 × 10−3 (mm3/N·m) for the sample prepared at 800 °C, which were over 10 times and one fifth of that of the aluminum matrix individually. This study provides a new strategy for developing 316 L lattice/Al composites with excellent properties.

Microstructure and corrosion behavior of A390-10 wt% SiC composite-AA2024-T6 aluminum alloy dissimilar joint: Effect of post-weld heat treatment

The weldability of aluminum matrix composites to other materials, such as aluminum alloys, is an essential point in expanding the use of these materials. This study investigated the effect of rotational speed and post-weld heat treatment on the microstructure, mechanical properties, and corrosion behavior of A390-10 wt% SiC composite/AA2024-T6 aluminum alloy dissimilar joint. Friction stir welding is performed using a square frustum pyramid pin tool with a rotational speed of 400–1200 rpm and a traverse speed of 40 mm/min. Results found that a surface groove formed on the weld crown at a rotational speed lower than 800 rpm due to insufficient material flow. Also, the tunnel defect formed on the advancing side at a rotational speed higher than 1000 rpm due to the turbulent flow of material. By increasing rotational speed from 800 to 1200 rpm, the average grain size of the advancing and retreating sides increased by 41.1 and 46.3 %, respectively. Compared to AA2024-T6 and A390-10 wt% SiC composite base metals, the average hardness of the stir zone of the joint fabricated by the rotational speed of 800 rpm increased by 8.4 and 38.2 %, respectively. By increasing the rotation speed from 800 to 1000 rpm, the yield strength and ultimate tensile strength decreased by 6.8 and 6.5 %, respectively. By decreasing rotational speed from 1000 to 800 rpm, the elongation and corrosion resistance decreased by 5.4 % and 34.7 %, respectively. After post-weld heat treatment, the hardness, yield strength, ultimate tensile strength, and corrosion resistance increase 15.9, 12.7, 7.8, and 28.9 %, respectively.

Influence of cutting speed and particulate content on polycrystalline diamond tool wear in machining AA7075/TiB2 in situ aluminum matrix composites

Aluminum alloy AA7075 was reinforced with in-situ synthesized TiB2 particles (0–12 wt%) to prepare aluminum matrix composites (AMCs) by casting. The cast composite bars were machined using polycrystalline diamond (PCD) tool inserts. The influence of cutting speed and TiB2 particle content on the tool wear was quantified. The rake face, flank face, and machined surface morphologies were studied using a field emission scanning electron microscope (FESEM). Energy dispersive X-ray analysis (EDS) was carried out on the rake face across a defined line. The increase in cutting speed and TiB2 particle content increased the tool wear. The highest cutting conditions accelerated tool wear and caused chipping. The mechanisms responsible for tool wear were identified as adhesion, abrasion, chipping and diffusion. The state of the tool wear was directly reflected on the machined surface in the form of deposited material and feed mark ridges.

Field-assisted sintering of high-entropy alloy-reinforced aluminium matrix composites: phase identification and microstructural properties

This study investigates the design, phase identification, and microstructural properties of high-entropy alloy (HEA)-reinforced aluminium (Al) matrix composites. Thermophysical expressions for HEAs were employed during the design phase of the HEA; both theoretical frameworks and experimental analyses were used to anticipate stable phases while a field-assisted sintering technique was employed to consolidate the samples. Calculation of phase diagram (CALPHAD) predictions for the phases present in the HEA align with valence electron concentration (VEC) calculations as both predicted the presence of BCC and FCC phases. The microhardness results reveal a substantial increase in the hardness value of the composites as compared to the pure Al, such that as low as 5 wt% HEA addition resulted in over a 100% improvement, while the densification of the composites was found to decrease with an increase in the wt% of HEA. SEM micrographs and XRD analyses show fair dispersion, bonding, and phase integration in the HEA-reinforced composites.