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Stir-casting with ultrasonic cavitation produced nano-Al2O3-filled AA7150 matrix composites in this study. The SEM microstructure study shows that all composites include nano-Al2O3 particles with consistent particle sizes and homogenous distribution. EDS and XRD showed no secondary phases or impurities in the composite. Optical microscopy showed intense ultrasonic cavitation effects, and nano-Al2O3 particles caused grain refinement in the AA7150 matrix. The composite's mechanical characteristics improved when the Al2O3 nanoparticle weight percentage (wt.%) increased. With only 2.0 wt.% nano-Al2O3 particles, the composites yielded 232 MPa, 97.52% higher than the sonicated AA7150 matrix alloy. Multiple models were used to characterize the strength of the AA7150 nano-Al2O3 composite. The findings showed that thermal incongruity, Orowan strengthening, the Hall–Petch mechanism, and load transfer effects contributed the most towards the increased strength of the composite. Increasing the nano-Al2O3 wt.% in the AA7150 matrix improved hardness by 95.08%, yield strength by 90.34%, and sliding wear resistance by 46.52%. This enhancement may be attributed to the combined effects of better grain refinement, enhanced dispersion with dislocation strengthening, and better load transfer between the matrix and reinforcement, which are assisted by the inclusion of reinforcements. This result was confirmed by optical studies. [ABSTRACT FROM AUTHOR]

The remarkable characteristics of aluminum alloys, like their hardness, strength-to-weight ratio, fatigue, corrosion resistance, play a decisive role in the aeronautical and automotive industries. However, scientists are on the lookout for substantial advancements in the wear resistance of the composites under varied service situations. This investigation focuses on the characteristics of hybrid metal matrix composites with regards to optical, physical, mechanical, tribological, and corrosion behavior of ADC12 alloy reinforced by born carbide and rice husk ash (RHA) particulates. The liquid metallurgy process with the stir casting technique was used to produce the hybrid composites, which were then compared to monolithic materials. In the fabrication, reinforcement RHA was added from 0 to 12 % while maintaining a born carbide content of 5 %. Following ASTM standards, the resulting composites were put through optical, several physical, mechanical, wear, and corrosion testing. The experimental findings were then analyzed. With a rise in the amount of reinforcement in the base alloy, physical and mechanical characteristics greatly improved, whereas the percentage of elongation was seen to decline. The effects of exposure time were studied on the hybrid composites on corrosion behavior in acidic environments. The composites are exposed to the hydrochloric acid solution, and weight loss over various periods, from 12 to 72 h, is measured in steps of 12 h. It was discovered that the corrosion resistance increased as the reinforcing content increased. By using a pin-on-disc apparatus, the wear tests were conducted, and the outcomes indicated the composites' superior wear resistance. Composites with a higher percentage of reinforcement displayed superior characteristics. Following the tensile testing, broken surfaces, wear, and corrosion morphology are examined in scanning electron microscope images. The research findings are thoroughly examined, and careful interpretations have been made. [ABSTRACT FROM AUTHOR]

The engineering sector researchers are always searching for new materials for their challenging applications. The aluminum alloy (AA) 357 plays a critical role in applications like automotive and aerospace because of its exceptional characteristics such as toughness, fatigue resistance, and more importantly strength-to-weight ratio, but it suffers from poor wear resistance. However, the research community is looking for enhancement in wear resistance at various loads. This research deals with AA357-Si3N4 nanocomposites fabricated through the induction stir casting method and evaluation of properties in comparison with AA357 matrix. The Si3N4 nanoparticulates were selected as reinforcement and added 0.5 to 3.0 wt.% in the steps of 0.5 wt.%. The influence of Si3N4 nano reinforcement content on hardness, strength, and wear resistance of AA357-Si3N4 nanocomposites investigative work was conducted as per ASTM standards. The studies of microstructures of AA357-Si3N4 nanocomposites were performed using an optical microscope to analyze grain structure and a scanning electron microscope (SEM) to examine particle distribution. The density, hardness, and ultimate tensile strength (UTS), in addition to morphological studies of fractured surfaces and energy dispersive spectroscopy for nanocomposites elemental study. As per ASTM G99, Standard Test Method for Wear Testing with a Pin-on-Disk Apparatus, standards, pin-on-disc equipment was used to examine tribological properties of AA357-Si3N4 nanocomposites and SEM pictures of worn nanocomposites surfaces analyzed extensively. By going through the experimental outcomes, it is realized that with increase in nano reinforcement in matrix AA357, the properties such as density, resistance to indentation/hardness, and UTS increased at the expense of percentage elongation. The pin-on-disc tribometer experimental results indicate that the fabricated AA357-Si3N4 nanocomposites have higher wear resistance. [ABSTRACT FROM AUTHOR]

The welding of steel and aluminum is difficult to join because of their differences in solid solubility, melting points, and formation of intermetallic compounds (IMCs), which may weaken the welded joints. Friction stir welding (FSW) has more feasibility for joining aluminum and mild steel (MS), but IMCs may form, affecting the joint properties. Friction stir extrusion (FSE) is a new derivative technique of FSW that reduces the tool wear and eliminates the formation of IMCs by forming mechanical interlocking joints at the interface. This present study applies the FSE process to join two dissimilar metals: Al6082 alloy and AISI 1020 MS. The FSE process is optimized by adjusting axial force, tool rotation rate, and traverse rate parameters. The mechanism of groove filling was observed and compared (at optimum parameters) with two different profile tools: one is a plain tapered tool and another is a tapered threaded tool; both were made of high-speed steel. The aluminum-MS joints were subjected to shear strength by conducting tension-shear tests using a dynamic servo-controlled fatigue testing machine, as per ASTM E466, Standard Practice for Conducting Force Controlled Constant Amplitude Axial Fatigue Tests of Metallic Materials. The hardness at the joint is evaluated by conducting Rockwell hardness tests, as per ASTM E18, Standard Test Methods for Rockwell Hardness of Metallic Materials. The microstructural characterization is done using optical electron microscope (OEM) and scanning electron microscope (SEM). The obtained results concluded that 30 mm/min is the optimum traverse rate for complete filling of the groove at 14.7-kN axial force and a tool rotation rate of 1,000 rpm. Furthermore, the discussions were made using hardness tests, OEM, SEM, and energy-dispersive spectroscopy analysis. [ABSTRACT FROM AUTHOR]

Surface composites are viable choices for various applications in the aerospace and automotive industries. Friction Stir Processing (FSP) is a promising method for fabricating surface composites. Aluminum Hybrid Surface Composites (AHSC) are fabricated using the FSP to strengthen a hybrid mixture prepared with equal parts of Boron carbide (B4C), Silicon Carbide (SiC), and Calcium Carbonate (CaCO3) particles. Different hybrid reinforcement weight percentages (reinforcement content of 5% (T1), 10% (T2), and 15% (T3)) were used in fabricating AHSC samples. Furthermore, different mechanical tests were performed on hybrid surface composite samples with different weight percentages of the reinforcements. Dry sliding wear assessments were performed in standard pin-on-disc apparatus as per ASTM G99 guidelines to estimate wear rates. The presence of reinforcement contents and dislocation behavior was investigated using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) studies. The results indicated that the Ultimate Tensile Strength (UTS) of sample T3 exhibited 62.63% and 15.17% higher than that of samples T1 and T2, respectively, while the Elongation (%) of T3 exhibited 38.46% and 15.38% lower than that of samples T1 and T2, respectively. Moreover, it was found that the hardness of sample T3 increased in the stir zone compared to samples T1 and T2, owing to its higher brittle response. The higher brittle response of sample T3 compared to samples T1 and T2 was confirmed by the higher value of Young's modulus and the lower value of Elongation (%). [ABSTRACT FROM AUTHOR]

A focus of the current industrial sector is motivated to develop a new class of advanced materials with superior characteristics compared to currently available conventional materials. In the recent past, light metals and alloys, such as aluminum, copper, titanium, and magnesium alloys and their metal matrix composites (MMCs) have been increasingly accepted in automotive, aerospace, and biomedical sectors. Moreover, for improving the physical and mechanical characteristics of these materials, the processing of materials with secondary metalworking techniques (severe plastic deformation [SPD], complete and partial heat treatment processes, cryogenic treatment, surface coatings, etc.) is essential. Out of several secondary metalworking techniques, the most efficient is the SPD technique with equal channel angular pressing (ECAP). ECAP is widely adopted to produce materials with significantly reduced grain size and excellent properties. The current review article aims to present the effect of ECAP on the physical and mechanical characteristics of aluminum, copper, titanium, and magnesium alloys, and their MMCs are discussed. Microstructural studies and their associated statistical parameters of these materials are discussed using several destructive and nondestructive techniques. Also, the use of in-situ methods, such as digital image correlation, infrared thermography, etc., is examined to study the deformation mechanisms in ECAP. This review article provides a new direction for researchers working in materials engineering and science fields to recognize the importance of the ECAP technique on mechanical characteristics and associated microstructural changes of majorly used alloys and MMCs. [ABSTRACT FROM AUTHOR]

In recent times, the use of aluminum alloy-based Hybrid Metal Matrix Composites (HMMCs) is being increased in aerospace and automotive applications. HMMCs compensate for the low desirable properties of each filler used. However, the mechanical properties of HMMCs are not well understood. In particular, microstructural investigations and wear optimization studies of HMMCs are not clear. Therefore, further studies are required. The present study is aimed at fabricating and mechanical and wear characterizing and microstructure investigating of Silicon Carbide (SiC) and Graphite (Gr) added in Aluminum (Al) alloy Al6061 HMMCs. The addition of SiC particles was in the range from 0 to 9 weight percentage (wt.%) in steps of 3, along with the addition of 1 wt.% Gr in powder form. The presence of alloying elements in the Al6061 alloy was identified using the Energy Dispersive X-Ray Analysis (EDX). The dispersion of SiC and Gr particles in the alloy was investigated using metallurgical microscope and Scanning Electron Microscopy (SEM). The gain in strength can be attributed to the growth in dislocation density. The nature of fracture was quasi-cleavage. The microstructure examination reveals the uniform dispersion of the reinforcement. Density, hardness, and Ultimate Tensile Strength values observed to be increased with increased contents of SiC reinforcement. Besides, wear studies were performed in dry sliding conditions. Optimization studies were performed to investigate the effect of parameters that affecting the wear. The sliding wear resistance was noticed to be improved concerning higher amounts of reinforcement leading to a decrease in delamination and adhesive wear. The predicted values for the wear rate have also been compared with the experimental results and good correlation is obtained. [ABSTRACT FROM AUTHOR]

The paper focused on an experimental study on the microstructural, mechanical, and wear characteristics of 15 wt.% alumina (Al2O3) particulates with an average particle size of 20 µm, reinforced in Al2014 alloy matrix composite as-cast and heat-treated samples. The metal matrix composite (MMC)samples were produced via a novel two-stage stir-casting technique. The fabricated composite samples were subjected to evaluate hardness, tensile strength, fatigue behavior and wear properties for both as cast and T6 heat-treated test samples. The Al2014 alloy and Al2014-15 wt.% Al2O3 MMCs were in solution for 1 h at a temperature of 525 °C, quenched instantly in cold water, and then artificially aged for 10 h at a temperature of 175 °C. SEM and X-ray diffraction analyses were used to investigate the microstructure and dispersion of the reinforced Al2O3 particles in the composite and the base alloy Al2014. The obtained results indicated that the hardness, tensile and fatigue strength and wear resistance increased when an amount of Al2O3 particles was added, compared to the as-cast Al2014 alloy and it was observed that after subjecting the same composite samples to heat treatment, there was further enhancement in the mechanical and wear properties in the Al2014 matrix alloy and Al2014-15 wt.% Al2O3 composite samples. [ABSTRACT FROM AUTHOR]

The present study is aimed at fabricating and determining the physical, mechanical, and tribological properties of Al6061 alloy reinforced with Titanium Diboride and Graphite particles. The different weight percentages of hybrid particles (Titanium Diboride – Graphite) dispersed in the Al6061 matrix for fabricating hybrid metal matrix composites (HMMCs) using a stir casting method. The amount of titanium diboride reinforcement addition in the Al6061 matrix was in the range from 0 to 6 wt% whereas the fixed graphite reinforcement of 4 wt% was added. Optical Microscopy, Scanning Electron Microscopy and Energy Dispersive Microscopy studies were used to investigate the microstructure of the developed composite materials. The uniform distribution of reinforcement particulates in the matrix was observed. The addition of particulate reinforcements results in the enhancements of the mechanical properties such as density, hardness, with the expense of elongation. The tribological dry sliding wear experiments were carried out using a pin-on-disc tribometer. The Al6061-6%TiB2-4%Gr HMMCs reinforced composites exhibited the highest hardness and ultimate tensile strength and the lowest percentage elongation. Also, Al6061-6 percent TiB2-4%Gr samples had the best wear resistance. The increase in bonding by adding the optimum weight percentages of hybrid particles in the matrix could be the reason for this. The pristine Al6061 matrix exhibited the opposite trend. [ABSTRACT FROM AUTHOR]

In recent times, industries are focusing to develop newer materials with superior properties compared to the materials available at present. In this regard, the present investigation is aimed at the fabrication and evaluation of the physical, mechanical and tribological properties of Al6061 alloy reinforced with Titanium Diboride particulates. The Al6061-titanium diboride composites were fabricated via liquid metallurgy route. The amount of reinforcement addition in the Al6061 was varied from 0 to 6 wt% in the steps of 2. The physical, mechanical & tribological experiments were conducted on the Al6061 alloy and its titanium diboride composites as per ASTM Standards. As per the obtained results, it can be understood that with the increase in weight percentage of titanium diboride reinforcement, the properties like density, hardness and strength increased with the decreasing elongation. The wear experiments were carried out on pin-on-disc tribometer and results indicate that the fabricated Al6061-TiB2 composites showed higher wear resistance. Out-off all the compositions considered in the current work, the Al6061-6 wt% TiB2 composite material displayed improved properties. The optical, scanning electron, and energy dispersive microscopy images were used to study the composites before and after the casting, fractured and worn-out surfaces. [ABSTRACT FROM AUTHOR]

Aluminum matrix composites are often preferred in automotive, aerospace, and ship building, owing to their enhanced properties over conventional aluminum alloys. Aluminum metal matrix composites reinforced with particulates extend improved wear resistance and mechanical properties. In this article, the test inferences of physical, mechanical, and tribological properties of Al6061 matrix reinforced with boron carbide (B4C) are explained. Composites were processed that contained 0 to 3% B4C by weight, in steps of 1%. The method used for manufacturing the casting is the stir casting route (liquid metallurgy). All testing was conducted according to ASTM standards. The results of density obtained from the experiments are compared with the density as calculated from the rule of mixtures. The resistance to deformation and ultimate tensile strength improved with the addition of particulate reinforcement, but not at the cost of ductility. The ductility has been stored, to some extent. The effect of reinforcement on composites has been further confirmed by a Pareto chart, an interaction plot obtained from Minitab software. The tests were conducted in randomized order. The dry sliding wear of the composites with B4C reinforcement displayed the greater resistance to wear in comparison with unreinforced Al6061 alloy. [ABSTRACT FROM AUTHOR]

Aluminum matrix composites are often preferred in automotive, aerospace, and ship building owing to their enhanced properties over conventional engineering aluminum alloys. In this article, the results of the investigations on the mechanical properties and sliding wear behavior of aluminum-tungsten carbide (WC) composites are presented and discussed. Metal matrix composites of Al6061 containing different percentages of WC were prepared by powder metallurgy techniques. All testing was conducted according to ASTM standards. The dry sliding wear tests were conducted at a constant velocity and load varying from 10 to 40 N. The composite density was found to increase with greater filler contents and is further in agreement with the values of theoretical density. The Brinell hardness and ultimate tensile strength of the composites increased with a greater ceramic phase and decreased filler size, with a decrease of percentage elongation. The dry sliding wear of the composites with WC reinforcement displayed the greater resistance to wear. [ABSTRACT FROM AUTHOR]

The present investigation mainly concentrates on work done in order to explore physical, mechanical & tribological characteristics of Al6061 alloy reinforced with nano-sized zirconium dioxide particulates. Four casts of different percentages of reinforcement from 0 to 6 wt% in the steps of 2 are fabricated using liquid metallurgy technique (stir casting). The prepared composites later subjected to various physical, mechanical & wear tests and results were studied. The tests were carried out in accordance with the ASTM standards on the alloy and nano-composites. In the present investigation the physical and mechanical properties like density, hardness and tensile strength increased significantly with the increase in percentage of reinforcement in the matrix alloy, while the percentage elongation found to be decreased. The sliding wear tests were performed by using pin-on-disc the tribometer and results indicated that wear resistance of composites was higher. Off the four compositions, there were improved properties of composites with higher weight percent of reinforcement. Scanning Electron Microscope (SEM) micrographs was used after tensile testing to study fractured surfaces of specimens and wear morphology after wear testing. Overall the investigational outcomes are very interesting and motivates to do further more research., (© 2019 Published by Elsevier Ltd.)