Al Matrix Composites Research Articles

A Review of FSW on Al Matrix Composites (AMCs)

A Review of FSW on Al Matrix Composites (AMCs)

A Review of FSW on Al Matrix Composites(AMCs)

A Review of FSW on Al Matrix Composites(AMCs)

Machinability study of Al and Mg-based metal matrix composites using wire-EDM

In this investigation, a machinability study of the fabricated aluminium (Al) and magnesium (Mg) based MMCs is done using the Wire-EDM process. Initially, Al and Mg-based MMCs are fabricated with Silicon Carbide (SiC) reinforcements particles by the bottom pouring type stir casting process. After that, successful machining of both Al and Mg-based MMCs is carried out using Wire-EDM. The lowest value of machining time and kerf width for both Al/SiC and Mg/SiC MMCs are observed (0.1732 min, 0.3270 mm) and (0.1980 min, 0.2970 mm) respectively. The highest value of material removal rate 71.6651 mm3/min and 53.1313 mm3/min are achieved correspondingly for the Al and Mg-based MMCs. Overall evaluation criteria (OEC) values are calculated for all machining conditions to find out the mean effect of all process parameters simultaneously. The highest calculated OEC value of 75.00 and 84.45 are observed intended for Al/SiC and Mg/SiC respectively.

A study on the formation of multiple intermetallic compounds of friction stir processed high entropy alloy particles reinforced Al matrix composites

In this paper, AlCoCrFeNi high-entropy alloy (HEA) particles was used as the reinforcement for aluminum matrix composites fabricated by friction stir processing. HEA particles were uniformly dispersed in the aluminum matrix. The formation of multiple intermetallic compounds and interface behavior were closely evaluated. The HEA-Al interface consisted of Al13(CoCrFeNiMg)4, Al9(CoFeNi)2 and Al18Cr2Mg3, and the interface formation and growth behavior were investigated by coupling the thermodynamics and kinetics factors. The low effective Gibbs free energy of Al13(CoCrFeNiMg)4 and Al9(CoFeNi)2 phases is the thermodynamic nature of their generation at the interface. Compared with as-received Al, the fabricated composites exhibited 16.8% higher yield strength and 28.1% higher tensile strength, and the elongation was retained to 15.3%. Both of brittle and ductile fracture characteristics were observed on the surface of the HEA particles.

Predicting impact strength and hardness of aluminium & tungsten carbide nano-composite synthesized by PM

This Study deals with mechanical and microstructural properties with pure aluminum and tungsten composite fabricated by powder compaction process. The scope of the research work is the production and characterization of Al matrix composites reinforced with WC ceramic nanoparticles. The synthesis process was powder metallurgy. Compacted specimens of Aluminum with varying tungsten carbide percentages and varying APS are tested using impact testing machine. Simulations for the impact tests were performed on composite specimens prior to actual fabrication and mechanical testing. Good correlation was observed between simulated specimens and fabricated specimens. Significant differences in the impact strength values were observed.

In-situ formation of particle reinforced Aluminium matrix composites by laser powder bed fusion of Fe2O3/AlSi12 powder mixture using laser melting/remelting strategy

In-situ preparation of particle reinforced Al matrix composites (PRAMCs) by laser powder bed fusion (LPBF) is a promising strategy to strengthen Al-based alloys. The laser-driven thermite reaction can be a practical mechanism to in-situ synthesise PRAMCs. However, the introduction of elements oxygen by adding Fe2O3 makes the powder mixture highly sensitive to form porosity and Al2O3 film during LPBF, bringing challenges to prepare dense materials. This work develops an LPBF processing strategy combined with consecutive high-energy laser melting scanning and low-energy laser remelting scanning to prepare dense PRAMCs from Fe2O3/AlSi12 powder mixture. A high relative density (98.2 ± 0.55 %) was successfully obtained by optimising laser melting (Emelting) and remelting energy density (Eremelting) to Emelting = 35 J/mm2 and Eremelting = 5 J/mm2. Results reveal the necessity to increase Emelting to improve metal liquid’s spreading/wetting by breaking up Al2O3 films surrounding molten pools; however, the high-energy laser melting produced much porosity. Low-energy laser remelting could close the resulting internal pores, backfill open gaps and smoothen solidified surfaces. Although with two-times laser scanning, the microstructure still shows fine cellular Si networks with Al grains inside (grain size 370 nm) and in-situ nano-precipitates (Al2O3, Si and Al-Fe(-Si) intermetallics). Finally, the fine microstructure, nano-structured dispersion strengthening and high-level densification strengthen the prepared in-situ PRAMCs, reaching yield strength of 426 ± 4 MPa and tensile strength of 473 ± 6 MPa. Furthermore, the results can provide valuable information to process other powder mixtures with severe porosity/oxide-film formation potential considering the evidenced contribution of laser melting/remelting strategy to densify material and obtain good mechanical properties during LPBF.

Ablated surface morphology evolution of SiCp/Al composites irradiated by a nanosecond laser

Metal matrix composites are widely used in aircraft and aerospace components due to their low weight and high strength. Since their processing by conventional methods is quite problematic, laser processing techniques have to be used and optimized. In this study, two SiC particle-reinforced Al matrix composites with different volume refractions and average particle sizes, namely SiC p /AA2024 (45%, 30 μm) and SiC p /AA6061 (60%, 3 μm) were irradiated by a nanosecond laser with a pulse fluence range of 0.68–6.83 J/cm 2 . The ablated surface morphology evolution was studied by SEM, and the elements' distribution was analyzed by EDS. At increased pulse fluence, the molten matrix firstly spilled from spaces between silicon carbide particles and then spread on their surfaces, forming a smooth surface in the first composite with small particle size but failing to cover SiC particles in the second one with large particle size. The SiC particles on the laser-treated surface were seriously oxidized, while distributions of Al and Si elements on the laser-ablated surfaces were independent. The dispersion of Si element increased with the fluence. The ablation threshold and surface roughness of SiC p /AA6061 was lower than those of SiC p /AA2024, in contrast to the ablation depth. The performed thermal simulation confirmed the heat conduction existence between the matrix and reinforcement, as well as the particle's volume refraction and average size effects on the heating behavior of SiC p /Al composites. The results obtained are considered instrumental in substantiating the applicability of various laser processing techniques to SiC particle-reinforced Al matrix composites. • The ablated surface evolved from aluminum pre-melting, spilling out, spreading on surface, and wrapping particles up when fluence increased. • For small-sized particle-reinforced SiC p /AA6061, the molten aluminum is easier fused overspreading small SiC particles and formed an physically integral layer. • The Si and Al chemical distributions on the ablated surface were independent, but the Si element’s dispersion increased with the pulse fluence. • The ablation threshold and surface roughness of SiC p /AA6061 was lower than those of SiC p /AA2024, in contrast to the ablation depth.

Deformation Behavior and Mechanical Properties of Rolled Carbon Fiber Reinforced Al-Matrix Composites Via Protection with Sn Layer

Deformation Behavior and Mechanical Properties of Rolled Carbon Fiber Reinforced Al-Matrix Composites Via Protection with Sn Layer

SiC particle reinforced Al matrix composites brazed on aluminum body for lightweight wear resistant brakes

Aluminum alloys are well known light-weight alloys and very interesting materials to optimize the strength/weight ratio in order to reduce automotive vehicle weight, fuel consumption and CO2 emissions; unfortunately, they are also relatively soft and therefore cannot be used for high wear applications.The aim of this work was to develop an aluminum alloy brake disc with wear-resistant SiC particle reinforced aluminum matrix composites (SiC/Al) joined on to its surface.Different approaches based on brazing or shrink fitting joining technologies were used to join SiC/Al to the aluminum alloy surface.A functional graded structure was built by brazing thin layers of aluminum matrix composites reinforced with progressively higher amount of SiC particles by using a Zn–Al based alloy as joining material. Several samples were prepared by shrink fitting and brazing: 40 mm x 40 mm x 10 mm samples and a 100 mm diameter brake disc with 68% SiC particle reinforced Al matrix surface and aluminum alloy A365 body. Tribological tests demonstrated that an aluminum alloy brake disc with wear-resistant SiC particle reinforced aluminum matrix composites (SiC/Al) brazed on its surface is a promising technical opportunity.

Remarkable improvement of mechanical properties of layered CNTs/Al composites with Cu decorated on CNTs

Interfacial bond and structure as key points significant restrict the mechanical properties of carbon nanotubes (CNTs) reinforced aluminum matrix composites (CNTs/Al composites). In order to further enhance the interfacial bond of CNTs/Al composites, this paper proposed a novel fabrication process of CNTs/Al composites with Cu nanoparticles decorated CNTs, which results in the remarkable improvement of strength and ductility of CNTs/Al composites. The in-depth study results from microstructure of layered CNTs/Al composites show that: Cu nanoparticles can repair CNTs structural defects, and passivate the reaction activity of the defect points, which successfully inhibit producing big Al4C3 phase. On the other hand, Cu nanoparticles as a bridge connecting Al and CNTs, can improve the interface wettability, and produce an “Al-Cu-CNT” interlocking effect. Due to the improvement of the interfacial bond and structure between CNTs and Al matrix, the strengthening and toughening effect of CNTs is effectively exerted in the Al matrix composites. Additionally, this work avoids the traditional mismatch relationship between strength and ductility in CNTs/Al composites.

Comparative Study on the Corrosion Resistance of 6061Al and SiC3D/6061Al Composite in a Chloride Environment.

Interface problems and the destruction of the continuity of the oxide film in the Al matrix usually reduce the corrosion resistance of the material. In this paper, the corrosion resistance of Al matrix composites (AMCs) was improved by introducing the silicon carbide skeletons (SiC3D) obtained with polymer replica technology. SiC3D/6061Al was fabricated by infiltrating molten 6061Al alloy in the oxidized SiC3D using the low-pressure casting method. The corrosion resistance performances of 6061Al and SiC3D/6061Al in NaCl solution were studied by electrochemical, neutral salt spray corrosion (NSS), and salt leaching (SL) tests. Results show corrosion resistance of SiC3D/6061Al is higher than that of 6061Al alloys by open circuit potential (OCP), potentio-dynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) tests. However, NSS and SL tests show the corrosion resistance of SiC3D/6061Al is lower than that of 6061Al alloy. The reason is a corrosion resistant and anti-oxidation network macrostructure with large interface recombination, few concentrated interfaces, and a small specific area that formed in SiC3D/6061Al. SiC3D cannot damage the continuity of the Al2O3 passivating film, and the network macrostructure greatly improves the corrosion resistance performance.

Effect of reinforcement volume fraction and T6 heat treatment on microstructure, thermal and mechanical properties of mesophase pitch-based carbon fiber reinforced aluminum matrix composites

To meet the requirements of structural and functional integration, machinability and workability of engineering materials, continuous mesophase pitch-based carbon fiber (MPCF) reinforced 2024 aluminum (Al) matrix composites with 20–50 vol % MPCF were fabricated by vacuum hot pressing method. The effects of MPCF volume fraction and T6 heat treatment on microstructure, thermal and mechanical properties of MPCF/2024Al composites were investigated. The results show that the interface of the as-sintered composite was well bonded. After T6 heat treatment, the amorphous layer at the interface changed from continuous to discontinuous and the interfacial bonding was further improved, but there was no interfacial reaction. The increase of MPCF volume fraction was beneficial to improve the thermal conductivity (TC) and elastic modulus (E) of the as-sintered composites, up to 258.3 W/(m⋅K) and 343.5 GPa respectively, while the composites with 30 vol % and 40 vol % MPCF respectively had the highest ultimate tensile strength (UTS) and a coefficient of thermal expansion (CTE) close to zero. After heat treatment, the TC and E were slightly changed, while the CTE was further reduced and UTS was significantly improved. In this work, the heat-treated composite with 30 vol % MPCF had the highest UTS of 499.3 MPa and good thermal properties, and the TC of this composite may be further improved by using MPCFs with higher TC. Therefore, this composite is expected to become a promising engineering material integrating structure and function.

Insight of high-entropy alloy particles-reinforced 2219 Al matrix composites via the ultrasonic casting technology

The microstructure and mechanical properties of metallic composites can be favorably modified by the introduction of various reinforcing particles. Different contents of high-entropy AlCoCrFeNi alloy particles (HEAps) were individually injected into the 2219 Al alloys via ultrasonic casting technology. Some irregular HEAps were observed along the grain boundaries. They served as reinforcing factors and provided numerous potential heterogeneous nucleation sites on the α-Al matrix. The average grain size of the HEAps-reinforced aluminum matrix composites (HEAps/AMCs) reduced dramatically from 136.08 μm (0 wt%) to 34.95 μm (1.5 wt% HEAps). Several rich-Al, Co, Fe, Cr, Ni, Cu elements with needle-shaped phases accompanied by some distinctive plate-like precipitates were observed in the Al matrix. Additionally, the optimal addition of HEAps was approximately 1.5 wt%, for any excess was detrimental to the microstructure and properties. The HEAps had a substantial influence on the mechanical properties, namely 1.5 wt% corresponding to the optimum tensile strength (217.4 MPa), and 3 wt% ascribing to the maximum micro-hardness (120.5 HV). The primary strengthening mechanisms were explored, revealing the grain refinement, solute, and precipitate strengthening to be the dominant factors. However, ∆ σ CTE and ∆ σ EMM showed very limited contribution. Meanwhile, ∆ σ Load , ∆ σ WH1 , and ∆ σ WH2 offered marginal increments to the yield strength. Theoretically, a novel strengthening model was established, and the yield strength of the HEAps/AMCs in an optimal HEAps addition range was effectively predicted. • AlCoCrFeNi HEAps/2219 Al matrix composites are fabricated via ultrasonic casting. • HEAps were stochastically distributed along the grain boundaries. • Novel model was established to predict the yield strength of HEAps/AMCs.

Molecular dynamics investigation of atomic mixing and mechanical properties of Al / Ti interface

With the urgent lightweight demand in the aerospace engineering and transportation industries, Al / Ti composite structures have attracted much interest due to their excellent performances compared with conventional materials. Computational simulations have contributed to the understanding of both fundamental and practical aspects of fabrication of such composites and studying of their properties. The present work reports the results of studies based on molecular dynamics simulations on the mechanical properties of an Al / Ti composite obtained by compression combined with shear strain. Tensile properties of a nanosized Ti / Al composite consisting of two single crystals obtained after different compression rates are analyzed. The loading scheme applied in the present work is a simplification of the scenario experimentally realized previously to obtain Al-matrix composites. It is confirmed that uniaxial compression combined with shear deformation is an effective way to obtain the composite structure since severe plastic deformation facilitates the diffusion process. The results indicated that a symmetrical atomic movement took place in the Ti / Al interface during deformation. However, Al atoms diffuse into the Ti block easier than Ti atoms into the Al block. Tensile tests showed that fracture took place in the Al part of the final composite sample, which means that the interlayer region where the mixing of Ti and Al atoms is observed is stronger than the pure Al part.

Microstructure, tensile and impact behaviour of Si3N4 particles reinforced Al2024 matrix composites

Aluminium MMC’s are used in wide range of applications because of its strength to weight ratio and enhanced mechanical properties due to addition of reinforcement. Different types of reinforcement helped in enhancement of mechanical properties either a hybrid or single reinforcement. In this work we carried out reinforcement of Si3N4 with Al2024 alloy. Aluminium 2000 series has good toughness, ductility and fatigue resistance compared to other series. Liquid metallurgy technique process is adopted and stir casting process is carried out to prepare Al2024-Si3N4 composite. 4 and 8 wt% composition of Si3N4 in aluminium alloy. Tensile and impact test are conducted to know the elastic property and toughness of the material. Yield strength, tensile strength and elongation percentage is increased till 4 wt% of Al2024-Si3N4 and decreased for 8 wt% of Al2024-Si3N4. The Impact resulted showed the same, increase for 4% and decrease for 8%. Microstructural analysis is done with the help of scanning electron microscope to know the distribution of Si3N4 in Al2024 alloy.

Microstructure and tensile behaviour of B4C particles reinforced Al6061 matrix composites

In an ongoing work an exertion is made to get fabrication of aluminium 6061 matrix composites reinforced with 8 µm average size of 7 wt% B4C particulates of with two stage melt stirring fabrication technic and are examined under scanning electron microscopy, Energy Dispersive X-ray Spectroscopy, and X-ray diffractometer to characterize the surface morphology, chemical elements and its percentage of distribution in addition to phase elements of composites. Then evaluation of prepared composite for Hardness and Tensile properties using micro hardness testing machine and UTM machine at room temperature are carried as per ASTM standards and found that Al6061-7 wt% B4Cp composite material’s hardness, Yield stress and ultimate tensile strength are magnified by 24.15%, 15.17% and 23.577% respectively while percentage of elongation is sink by 39.07% as compare to Al60610 alloy. Finally, the tensile facture surface was examined for micro mechanisms of failure and its surface morphology stipulates ductile kind of fracture and frail interface leading to facture mechanism.

High-strength Al matrix composites reinforced with uniformly dispersed nanodiamonds

Poor dispersion of nanodiamonds (NDs) is the bottleneck to exploit their intrinsically excellent properties in metal matrix composites (MMCs). In this study, a strategy of surface modification was developed to uniformly disperse ND particles into 2024 aluminum alloy. Microstructure observations showed that individual NDs are closely contacted with the matrix, forming reaction-free interfaces. Consequently, a high-strength 0.8 vol% ND/2024Al composite with an ultimate tensile strength of 741.0 MPa is developed. Theoretical and experimental measurements prove that the strength improvement of ND/2024Al composite is mainly attributed to the Orowan strengthening, thermal mismatch strengthening and grain refinement strengthening. This work demonstrates the effective application of NDs as a reinforcement for MMCs towards high-specific-strength materials.

Effect of the Hot Deformation Conditions on Structure and Mechanical Properties of AlCr/AlCrSi Powder Composites

Aluminum matrix composites usually contain strengthening particles of refractory compounds (SiC, Al2O3) that do not react with the Al matrix. There is a problem in producing the Al matrix composite with inclusion of metals that can generate intermetallic compounds with aluminum. In this case, a conventional sintering of powder mixtures results in high porosity due to volume growth. That is why some new methods of producing dense Al matrix composites are required. A possibility to create a dense powder Al-based composite containing hard components, such as chromium and silicon, without using the sintering process, is considered. This paper presents study results of structural and mechanical properties of Al-Cr and Al-Cr-Si composites produced by hot compaction of powder mixtures. An analysis of the relationship between mechanical properties and structures of Al-Cr and Al-Cr-Si composites is carried out. Optimal values for thermomechanical processing modes that ensure sufficient strength and plasticity are determined. It is shown that strong bonding of the aluminum particles occurs under hot deformation, and an aluminum matrix is formed that provides acceptable composite bending strength as a result. The presence of chromium and silicon hard inclusions is not a significant obstacle for aluminum plastic flow. Al-Cr and Al-Cr-Si composites produced by hot deformation of the powder mixtures can be used as cathode material for the deposition of wear-resistant nitride coatings on metalworking tools.

Influence of Welding Process on Microstructure and Properties of Laser Welding of SiCp/6061 Al Matrix Composite

Direct laser welding, laser welding with Ti interlayer, and ultrasonic-assisted laser welding with Ti interlayer were used to join SiCp/6061 Al matrix composites. Microstructural evolutions, compositional distributions and tensile strengths under three processes were compared and analyzed. The experimental results showed that ultrasonic-assisted laser welding with Ti interlayer can obtain joints with good continuity and without obvious defects. Due to combined effects of Ti interlayer and ultrasonic, formation of brittle Al4C3 phase was greatly suppressed and fine TiC precipitates were also uniformly distributed in weld metal. The strength shown by the welded joints could reach up to 77.2% of the strength of the base material. Because of the internal defects (voids and pores) and the generated large numbers of brittle phases of Al4C3 in weld metal, the joint strength shown by the other two techniques, direct laser welding and laser welding with Ti interlayer, only reached 49.4 and 64.8% of the base material strength, respectively.

Tribological behavior and mechanism of high proportion of ceramic particles reinforced Al composite

Al matrix composites reinforced with ceramic particles show excellent wear resistance and have great potential to replace convectional materials in many fields. In this paper, a high proportion (∼ 60%) of large ZrO2 particles reinforced Al matrix composites were manufactured by a high pressure infiltration method. The tribological behavior of the Al/ZrO2 composite and non-reinforced Al were investigated and compared using a GCr15 ball-on-disc apparatus under dry sliding wear condition. The microstructure, elements distribution and wear track morphology were analyzed to understand their tribological behavior and wear mechanisms. The wear rate of Al is 2.0 × 10−3 mm3 N−1 m−1, while the wear rate of Al/ZrO2 composite is only 0.15 × 10−3 mm3 N−1 m−1. The experimental results showed that Al is a combined wear mechanism of adhesive wear and abrasive wear. It also proved that the high proportion of large ceramic particle reinforced composite is stable under low load wear condition. The ceramic particles were firmly embedded in the Al matrix, and no ejection or removal of the particles was observed. The results showed that the wear mechanism of this composite is mainly three body abrasion in the stable wear stage.