Aluminum Alloy Composites Research Articles

Surface residual stress analysis of additive manufactured AlSi10Mg alloys

AlSi10Mg is a representative aluminum alloy composition used in additive manufacturing (AM), with good mechanical properties and light weight. However, high energy in the PBF process to overcome heat reflectivity induces thermal gradients and residual stress (RS) in products. In this study, surface RS in AM AlSi10Mg alloy parts was characterized using various non-destructive methods. The results of X-ray diffraction-based analysis (Williamson–Hall plot, sin2ψ, and cos α methods) and nanoindentation method were compared. In addition, the electron channeling contrast imaging (ECCI) technique was used for observation of dislocations within precipitates generated and coarsened by heat treatment. In the case of build direction, the tensile RS (46–188 MPa) of in as-built samples changed to compressive RS (28–51 MPa) after heat treatment. All of the applied approaches produced consistent trends in the results, although the W-H plot and nanoindentation methods differed, and the reason for this was discussed.

Property evaluation of AA 7075 based metal matrix composites reinforced with titanium carbide processed through microwave sintering

Ceramic reinforcements are becoming common phenomena to augment the deficiencies of light aluminium alloy composites more often in wear resistance. Assessment of wear resistance by pin on disc or ball on disc does not adequately represent the abrasion resistance realistically to the actual application. This paper deals with the outcome of experimental study carried out on sintered aluminium alloy 7075 composites reinforced with (5 wt%, 10 wt% and 15 wt%) titanium carbide (TiC) particles. The results show that coefficient of friction is increasing with respect to reinforcement percentage in conventional sintered composites whereas it is reducing with respect to increase in reinforcement percentage in microwave sintered composites. An attempt is also made to understand the effect of microwave sintering on the friction performance of the composite in comparison with conventional sintering. Wear mechanism is also presented based on optical micrographs of the scratched surface. Various hardness measuring methods were also carried out to study the influence of the methods on the hardness of the samples and illustrated the same.

Investigation on the mechanical properties of micro-sized B4C particles reinforced with FSW of aluminium alloy composites

The aluminum alloys AA7075 and AA6061 were successfully fused together using friction stir welding (FSW), which added the additional strength of B4C microparticles. As a function of processing factors like rotational and traversal speeds, the distribution pattern of B4C microparticles of varying volumes was investigated using mechanical properties. The refined grain structure brought on by dynamic recrystallization and pinning of distributed B4C particles in the SZ was found to considerably affect strain rate, tensile strength, and microhardness. An increase in the volume proportion of B4C particles improved the mechanical characteristics of FSWed joints. Joints made by Friction stir welding at 1200 rpm rotational and 45 mm/min traversal speeds with 10% B4C particles are around 15% harder than the hardness of as received AA7075 base material, with a microhardness of 189.15 HV and a tensile strength of 264.30 MPa.

An analysis on CNC machined surface roughness between AA7475 and AA7475/fly ash composite

The present investigation is the influence of limited reinforcement of fly ash (5 wt%) effects on surface roughness. In this regard, the fly Ash reinforced aluminium alloy (AA7475) composite was prepared and machined and measured the surface roughness to compared to aluminium alloy (AA7475). The sample size is 32 (16 for each tool) with 95% CI pre-test power 80% was used. The surface grinding operation is used to remove surface abnormalities. These pieces are machined in specific contour milling and are performed with different tools. Machined specimens are tested using a profilometer for calculating surface roughness and it was performed according to ASTM D3039 standards. The findings suggested that the plain aluminium alloy (AA7475) had a surface roughness of 0.51 mm and the composite aluminium alloy (AA7475) reinforced with 5 wt% fly ash had a surface roughness of 0.38 mm. The statistical value analysis yielded a significance value of 0.034 (p>0.05), indicating that there was substantial variation across the groups. In this research investigation, it was found that the surface roughness of a composite made of a 5 wt% fly ash augmented aluminium alloy (AA7475) was 32.27% lower than that of a plain aluminium alloy.

Tribological characteristics of aluminium alloy composites manufactured by liquid state casting process – A review

The global requirement for good quality and superior performing composites has led to research in hybrid metal matrix composite materials. In metal matrix composites, Al alloy composite has been chosen widely because of its high strength-to-weight ratio and superior wear resistance. Reinforcements like particulate Al2O3, SiC, fly-ash and graphite, etc. can easily be included in the melt using a liquid state casting process. In order to fulfil the essential need for elaborating their application, conventional stir casting method is employed which is economical for fabricating composite material when compared to other solid-state and liquid-state processes. This paper mainly focuses on the tribological properties and problems incorporated at the time of stir casting process of aluminium alloy composites containing one or more reinforcements. It provides inputs on the reinforcement incorporated, the matrix composition and the interface overlap and distribution each of which is critical in determining the performance of the composite. Processing AMMCs is straight forward using stir casting process, which is the most inexpensive and robust process that can be used on a wide scale, while other methods are confined to laboratories alone.

Effect of Boron Carbide Particles Addition on the Mechanical and Wear Behavior of Aluminium Alloy Composites

In this research, synthesis and assessment of the mechanical and wear possessions of Al7049-nano B4C composites are determined by experiments. Using the liquid metallurgy route, a stir casting technique was used to create composites with increasing concentrations of nano B4C from 3 to 9 weight %. Each composite’s reinforcement particles were heated to 400 degrees Celsius before being added to the molten Al7049 alloy in two separate steps, i.e., two-stage stir casting to optimise wettability and distribution. Scanning electron microscopy (SEM) was utilised to examine the microstructure, and energy dispersive spectroscopy (EDS) was utilised to determine the elemental make-up. Mechanical characteristics of composites were determined by subjecting them to tensile, compression, and hardness tests. Wear tests were conducted as per ASTM G99 standards with varying loads and speeds. Nanosized B4C particles were found to be dispersed throughout the sample space in a microstructural analysis. Hardness, ultimate strength, yield strength, and compression strength of Al7049 alloy composites were found to increase significantly as the weight percentage of nano B4C was increased. Additionally, compared to the unreinforced form, the ductility of the Al7049 alloy composites was slightly reduced. SEM micrographs of tensile-fractured specimens were used for research into the field of tensile fractography. Nano B4C reinforced composites exhibited superior wear resistance as compared to Al7049 alloy. These prepared composites can be used for wing root fitting of an aircraft.

Influence of Plasma Treatment on Surface Characteristics of Aluminum Alloy Sheets and Bonding Performance of Glass Fiber-Reinforced Thermoplastic/Al Composites.

This study focuses on modifying the surface of an AA 5052-H32 aluminum alloy using plasma treatment. Discharge power, exposure time, and working gas were adjusted as process parameters to improve the adhesion between the aluminum alloy and glass fiber-reinforced thermoplastic (GFRTP) polycarbonate composite. The surface composition and morphology of the aluminum alloy sheet were analyzed by X-ray photoelectron spectroscopy and scanning electron microscopy, and surface roughness and wettability were evaluated using a surface roughness-measuring instrument and contact angle goniometry, respectively. The bonding performance of GFRTP/aluminum alloy was also assessed. The surface of the aluminum alloy was subjected to chemical treatment prior to plasma treatment. The results revealed that nitrogen plasma treatment led to a substantial increase (25%) in bonding strength due to the synergistic effect of rough surface mechanical bonding and chemical bonding through functional groups between the aluminum alloy and GFRTP. However, the improvement in surface wettability by plasma treatment is time dependent and may gradually diminish over time due to the re-adsorption of hydrocarbon contamination from the surrounding air.

Tribological characterization of SiC/Co Hybrid Reinforced 6061 Aluminum alloy composites

Tribological characterization of SiC/Co Hybrid Reinforced 6061 Aluminum alloy composites

Structure and Properties of the "Cantor HEA Coating (Mn-Fe-Cr-Co-Ni) / Substrate (Alloy 5083)" System

Using the technology of cold metal transfer (wire-arc additive manufacturing combined with welding surfacing), a coating is formed on a 5083 alloy substrate with a high-entropy Mn-Fe-Cr-Co-Ni alloy of nonequiatomic composition. Analysis of the structure, elemental composition, and microhardness of the coating-substrate system is carried out using the methods of modern physical materials science. A significant increase (up to 9.9 GPa) in the microhardness of the material is found in the zone of contact between the coating and the substrate. The formation of lamellar inclusions (Al13F4) enriched in coating atoms in the zone of contact between the coating and the substrate is revealed. The high entropy coating in the contact zone has a submicrocrystalline grain-subgrain structure with a crystallite size ranging from 0.5 ^m to 1.1 ^m along the boundaries where nanosized particles of the second phase (Al3Ni) are revealed. The volume of grains contains a dislocation substructure in the form of randomly distributed dislocations or dislocation clusters. The scalar density of the dislocations is (0.8-1.0)-1010 cm-2. An assumption is made about the physical mechanisms of hardening of the material in the "coating-substrate" contact zone. Key words: high-entropy alloy, coating / substrate system, aluminum alloy, elemental and phase composition, microhardness, hardening.

High‐Stress Abrasive Wear Analysis of in Situ TiC‐Reinforced Zinc–Aluminum Composites Using Integrated Taguchi–TOPSIS Method

This study involves the preparation of in situ TiC‐reinforced zinc–aluminum alloy (ZA‐37) composites and analysis of their high‐stress abrasive wear behavior. The wear rate, friction coefficient, and frictional heating of the composites are investigated using a pin‐on‐disk wear tester. The experiments are carried out based on a plan created using Taguchi's technique. TOPSIS methodologies are used to determine the effects of applied load, abrasion distances, TiC contents on wear rate, coefficient of friction, and frictional heating throughout the wearing process. The results reveal that the composite with 10 wt% TiC exhibits the highest level of wear resistance among all samples. It is found that ploughing, microcutting, and delamination were the dominant wear mechanisms in general. However, in the optimum combination, mild abrasion and microploughing prevail. As per TOPSIS analysis, the reinforcement content affects the wear rate of test materials the most followed by applied load and abrading distance. Under the optimal combination of parameters, the in situ TiC composite has the potential of replacing the conventional gray cast iron utilized in bearing applications.

A Quantitative Method for the Composition of 7B05 Cast-Rolled Aluminum Alloys Based on Micro-Beam X-ray Fluorescence Spectroscopy and Its Application in Element Segregation of Recrystallization

Microscopic content segregation is among the important reasons for the anisotropy of mechanical properties in the cast-rolled sheets of the 7B05 aluminum alloy. It is of great significance to study the uniformity of aluminum alloys in terms of the microscopic composition and structure. In this study, a precise method for composition quantification based on micro-beam X-ray fluorescence spectroscopy is established by parameter optimization and a calibration coefficient. Furthermore, this method was applied for exploring and quantifying the relationship between recrystallization and deformation microstructures. The results show that the comprehensive measurement effects of all elements are the best when the X-ray tube voltage is 50 kV, the current is 150 μA, and the single-pixel scanning time is 100 ms. After verification, the sum of differences between the measured values and the standard values for all elements using the calibration coefficient is only 0.107%, which confirms the accuracy of the optimized quantitative method. Three types of segregation indexes in national standards were used to capture small differences, and finally ensure that the segregation degrees of elements are Ti > Fe > Cr > Cu > Mn > Zr > Zn > Al. The quantitative segregation results obtained by the spatial-mapping method show that the difference in the content of Al and Zn is approximately 0.2% between the recrystallization region and the deformation region, the difference in the content of Fe and Ti is 0.018% and 0.013%, the difference in the content of Cr, Cu and Zr is approximately 0.01%, and the difference in the content of Mn is not obvious, only 0.004%.

Mechanical characterization of high volume fraction Al7075-Al2O3 composite fabricated by semisolid powder processing

The mechanical properties and physical characteristics of aluminum alloy composites can be significantly improved by adding reinforcing phases. However, the high loading of the reinforcement phase in Al7075-Al2O3 composites has not been thoroughly studied. In this work, a combination of semisolid metal powder processing and powder metallurgy is used to process and manufacture Al7075-Al2O3 composites with a high reinforcement fraction of > 40 vol.%. The effects of processing parameters on the microstructures and mechanical properties of the composite material are discussed in detail. The loading limits of the high volume Al2O3 reinforcement in Al7075 composites are identified and linked to the processing parameters. A methodology is introduced to estimate the consolidation temperature of Al7075 alloy using compaction testing. Al2O3 particles (the average particle size of 120 µm) were mechanically milled with Al7075 powder (the average particle size of 20 µm) for 10 min and 5 h using a high-energy planetary ball mill. The mixture was then compacted in the semisolid state at 615 °C under the compaction pressures of 50 MPa and 100 MPa. By increasing the milling time from 10 min to 5 h, the deformation of aluminum powders and the fracture of Al2O3 reinforcement particles occur, restricting the loading limit of reinforcement. The milling time also shows a dominant effect on the powder morphology, microstructure, and mechanical properties of Al7075-Al2O3 composites. Increasing compaction pressure from 50 to 100 MPa significantly improved the compressive strength of the composite from 218 to 652 MPa. Al7075-Al2O3 composite with 40 vol.% of reinforcing phase exhibits the highest hardness of 198.2 HV and 96.9% relative density when it is milled for 5 h and compacted at 100 MPa. However, this composite shows the highest strength of 652 MPa when it is milled for 10 min. By increasing the reinforcing phase to 50 vol.% and 60 vol.%, the hardness, density, and compressive strength of composites decreased. The composites with 60 vol.% of reinforcing phase appeared overloaded. Results show that semisolid metal powder processing has huge potential for the fabrication of high loading Al2O3 in Al7075 matrix with near theoretical density.

Mechanical characterization and frictional wear behavior analysis on nano tungsten carbide and molybdenum disulfide particles reinforced aluminium 7075 composites

Hybrid metal matrix composites are gaining more importance in recent years. In this current investigation, aluminium alloy (AA7075) composites have been prepared with nano tungsten carbide (WC) and molybdenum disulfide (MoS2) as reinforcements using stir casting method and investigated. The nano tungsten carbide particles were added into the matrix in the proportions 0%, 0.5%, 1%, 1.5% and 2%, and molybdenum disulfide was added in the constant proportion of 5 wt.% to the molten metal. The prepared Al-hybrid composite samples were tested for their hardness, compression and tensile strength. Microstructure examination has also been performed to understand the distribution pattern of nano tungsten carbide and molybdenum disulfide particles in the base matrix by scanning electron microscope. From the results, it was found that there was steady improvement in composite properties when compared with the base metal while adding WC and MoS2. Thus, the prepared AA7075/MoS2/WC composites were guaranteed for high strength, hardness and exceptional microstructure stability. Dry sliding wear behavior on AA7075/MoS2/WC composites was investigated with the aid of pin-on-disc apparatus. Grey Relational Analysis tool was employed to identify the optimal setting of process variables, which results in lower wear rate and COF. The significance of factors such as sliding distance, sliding velocity and load on the wear characteristics was investigated by means of ANOVA. ANOVA results unveiled that load was the majorly influencing factor in attaining optimal wear characteristics. The tested samples have been investigated using scanning electron microscopy and reported.

Influence of Vanadium and Niobium Carbide Particles on the Mechanical, Microstructural, and Physical Properties of AA6061 Aluminum-Based Mono- and Hybrid Composite Using FSP

The ceramic particle reinforcement process is one of the most utilized techniques to enhance the metal surface. The current investigation uses vanadium and niobium carbides to reinforce the AA6061 alloy using the friction stir process (FSP). The mechanical properties are evaluated using ultrasound and conventional compressive tests; furthermore, the microstructure and physical properties are carried out to show the effect of single and hybrid additives of ceramic particles on the surface composites of aluminum alloy. Scanning electron microscopy (SEM) is utilized to examine the presence and distribution of the reinforcement VC and NbC particles inside the composite matrix. The microstructure examination revealed a good dispersion and homogenized distribution of the reinforcement particles. The results indicated that reinforcement particles significantly enhanced the mechanical and physical properties. The VC and NbC particles play an important role in improving the surface hardening behavior and grain refinement by restricting grain growth during the dynamic recrystallization process in the FSP action. The hybrid composited AA6061/NbC + VC recorded an increase in the compressive stress, yield stress, and hardness of 25%, 20%, and 50%, respectively, relative to the base metal, in addition to a 55% decrease in the coefficient of the thermal expansion (CTE) was reported. Moreover, the hybrid composite AA6061/NbC + VC significantly affected the corrosion rate with a reduction of 45%.

Influence of hybrid nanoparticles on the wear behavior of aluminum alloy composites for aerospace applications

PurposeEngineers and scientists are searching for novel materials with high performance on all aspect points of view for the applications including marine, aero and automobile fields. AA8090 aluminum alloy is one of the materials used in aero industries for aircraft construction because of its weight reduction ability. However, the AA8090 alloy has a drawback such as low wear resistance that affects the life time of material; hence, it should be addressed. The purpose of this investigation is to improve the wear resistance of AA8090 alloy.Design/methodology/approachIn this investigation, AA8090 aluminum alloy metal matrix composite was fabricated using different types of carbide nanoparticles such as vanadium carbide (VC), Cr3C2 and Mo2C by stir casting method and tribological and mechanical behaviors were studied.FindingsMechanical studies showed that the S1 sample displayed the maximum hardness of 142 HV and maximum tensile strength of 857 MPa because of the inclusion of hard VC particles. Tribological studies revealed that S1 sample showed high performance. A least wear rate of 0.003915 × 10–3 mm3/m was noted for S1 sample, which is 71% lower than the wear rate of S0 sample. Further, a least mass loss and lower coefficient of friction of 0.00152 g and 0.2, respectively, were observed for S1 sample because of its high hardness and high wear resistance because of the stuffing of high-hardness VC particles. Hence, it is concluded from this study that S1 sample, i.e. AA8090/VC, could be a better candidate for aerospace applications as it showed good tribological and mechanical properties.Originality/valueTo the best of the authors’ knowledge, this work is original and novel in the field of metal matrix composite which deals with the effect of hybridization on the wear performance of the aluminum alloy composites.

Tribological Characterization of Precipitation Hardened 7075 Aluminium Alloy Composites Reinforced with Cast Iron Particle

Tribological Characterization of Precipitation Hardened 7075 Aluminium Alloy Composites Reinforced with Cast Iron Particle

Manufacturing of AA7075 Aluminum Alloy Composites Reinforced by Nanosized Particles of SiC, TiN, and ZnO by High-Energy Ball Milling and Hot Extrusion

Manufacturing of AA7075 Aluminum Alloy Composites Reinforced by Nanosized Particles of SiC, TiN, and ZnO by High-Energy Ball Milling and Hot Extrusion

Investigation of the initiation and propagation of filiform corrosion on aluminum alloys by electrochemical techniques

ABSTRACT Filiform corrosion (FFC) is a type of localized corrosion commonly observed on coated aluminum alloys (AAs). Preceding research has focused on qualitative approaches of FFC on pure and binary metals. However, there is a lack of studies clarifying the FFC behaviour of commercial AAs. The present study aimed to investigate the FFC response of different AAs via electrochemical (EC) measurements. To do so, AAs 1100, 2024(Cu), 3003(Mn), 5052(Mg), 6061(Mg, Si), and 7075(Zn), were selected. Polarization measurements were carried out and three EC factors were identified from the polarization diagrams: resistance to FFC initiation (ΔEPR), driving force for propagation (ΔEcorr), and FFC kinetics (iFFC). To validate the EC results, accelerated exposure testing was performed. Coated AAs were placed in an environmental chamber and inspected; two parameters (number of threads (N) and filaments length (L)) were calculated and found to agree well with the EC factors. Results suggested that alloying elements Cu and Mg brought higher resistance to FFC initiation and slower FFC kinetics; that is, AA 2024(Cu) and 5052(Mg) showed the best resistance to FFC. In conclusion, the composition of AAs plays a significant role in their FFC susceptibility and EC measurements are effective for investigating the FFC behaviour of AAs.

The Role of Al4C3 Morphology in Tensile Properties of Carbon Fiber Reinforced 2024 Aluminum Alloy during Thermal Exposure.

The aluminum alloy drill pipe suffers long-term high-temperature conditions during ultra-deep well drilling. In this paper, the samples were prepared by vacuum hot pressing, followed by hot extrusion and T6 heat treatment. The mechanical properties of short carbon fiber reinforced 2024 aluminum alloy composites (SCFs/2024 Al) and the microstructure evolution at the interface region thermal exposure at 160 °C for 500 h are discussed. The experimental results showed that the effect of short carbon fiber on 2024 aluminum alloy remained steady throughout the whole process of the heat exposure experiment. The distribution and volume of interface products (Al4C3) changed with the prolonging of heat exposure time, and connected after coarsening. The evolution of the morphology of Al4C3 relieved the stress of the interface between carbon fiber and aluminum alloy matrix and enhanced the mechanical properties of the composite.

Investigation on energy-absorption-based protection mechanism of polyurea-coated aluminum alloy composite (PCAA) plate under impact loading by K9 glass projectile

To investigate the dynamic response and anti-impact characteristics of polyurea-coated aluminum alloy (PCAA) plates, impact experiments by the K9 glass projectile were first carried out with a light-gas gun. Based on the experiments, numerical simulations were conducted and validated using LS-DYNA software. After validation, the effect of polyurea coating thickness on the composite response as the impact surface under the same substrate conditions was discussed. The transverse diffusion effect and glassy transition effect were proposed in this study, and the results demonstrate better energy absorption characteristics and protective mechanisms of composite structures. The impact load is dispersed to a wider area due to the existence of polyurea coating on the impact surface characterized by the transverse diffusion effect, which will reduce the impact stress but deform a larger area plastically. In addition, our findings reveal that the glassy transition effect of polyurea determined by the average loading rate plays a significant role in improving the impact resistance characteristics of the composite structure. Finally, for the metal substrate with fixed thickness, this study demonstrates the existence of an optimal thickness of the coating as the impact surface of the PCAA plate to achieve the highest energy absorption efficiency under projectile impact conditions. The results and findings in this study provide a deep insight into the deformation and energy-absorption-based protective mechanism of PCAA targets under impact loading and may contribute to the future design of protective structures.