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New developments in thermal spraying processes may offer higher-quality alternatives to hard chrome plating and possibilities for hard chrome plating in a range of coating applications. These include spraying with high-velocity air fuel (HVAF) and new spray consumables. The low operating temperatures and accelerated particle velocity of the HVAF process enable investigation and development of a wide range of novel coating materials and applications. The High-velocity Air Fuel Process' quality and efficiency are primarily due to the broad combustion chamber and axial injection of the feedstock through it, as well as the relatively low combustion temperature of an air-fuel mixture and the low gas velocity that provides enough time for the mild heating of the powder particles. The current work discusses the inventive thermal spray procedure used for SAE 1008 carbon steel, a cost-effective substrate material. All of the compositions that were treated have undergone microstructure investigations. A scratch test is conducted in accordance with ASTM guidelines. Assessment of surface morphology clearly demonstrates the relationship between the evaluated parameters. According to the occurrence, scratch methods such as delamination, cracking, plastic deformation, and elastic deformation are highlighted. However, the findings of the scratch test showed that the samples' scratch resistance increased as the coating thickness rose. In comparison to samples with thinner coating, those with thicker coating demonstrated a stronger resistance to scratching. This is explained by the fact that coatings with a higher thickness and density can support the subsurface more effectively and stop cracks from scattering. This can retain the coating's integrity and stop more damage from occurring, improving scratch resistance. Better scratch resistance was displayed by the samples with denser microstructures and smoother surface morphologies. The outcome is greater scratch resistance because a higher density covering can withstand deformation and fracture better than a lower density layer. This is due to the mechanism of deformation and fracture in the coating material. This improvement in scratch resistance can be due to the composites' increased HVAF coating's hardness and adherence. The findings imply that using an HVAF coating to increase the scratch resistance of new nanocomposites may constitute a successful strategy. [ABSTRACT FROM AUTHOR]

The demanding material quality criteria in the automotive and aerospace industries have recently had an impact on the development of lightweight aluminium alloys. The choice and application of metal-matrix composites as structural materials in this context are known to offer a variety of benefits. These benefits include the ability to combine high elastic modulus, toughness, and impact resistance; minimum sensitivity to change in temperature or thermal shock; durability of the surface is good; moisture absorption leads to a potential issue while minimum exposure which leads to environmental degradation; and improved fabricability with conventional metalworking equipment. Aluminium metal matrix composites (AMMCs) are a potential material for advanced structural, aviation, aerospace, marine, and defense applications, as well as for the automotive sector and other related fields, due to their outstanding combination of qualities. The stir casting procedure is used to create an aluminium metal matrix composite (AMMC), which is the most efficient way to do so. In this study, the aluminium alloy 7075 is strengthened using neem leaf powder and SiC. The Vickers hardness examination method is used to govern the hardness of hybrid composites. Eventually, the mechanical and tribological properties of the composites were assessed, and their relationship to the composites' matching microstructure and wear was addressed. [ABSTRACT FROM AUTHOR]

The current research focuses on developing an Aluminium/Gr-CNT hybrid composite with two nanoscale reinforcements (Graphene and CNT). Stir casting was used to create hybrid composites with different weight fractions of graphene (1, 2, 3, and 5 Wt. %.) and a fixed CNT content of 2 Wt.%. The influence of varying graphene content with fixed CNT content on density, microstructure, hardness, and wear on hybrid MMC's was investigated. Hardness and wear tests were carried out as per ASTM E384 and G99 standards. Microstructure showed a relatively uniform dispersal of reinforcements (Gr and CNT) in pure Al matrix. The study revealed that the hardness of Al/Gr/CNT hybrid composites is higher than that of pure aluminium. The increase in hardness and addition of reinforcements lead to a significant reduction in wear rate. Wear surface morphology studies reported that pure aluminium had undergone an adhesion wear mechanism, whereas Al/Gr/CNT hybrid composites had undergone abrasion wear. [ABSTRACT FROM AUTHOR]

Metal matrix composites (MMCs) processed with significant technological interventions offer excellent properties at reduced cost resulted in a wide range of engineering applications. In MMCs, ensuring homogeneous dispersal of reinforcement in metal matrix to obtain aggregate properties in composites still remains as a challenging task. Industrial waste-based fly ash (FA) particles were used as a reinforcement material to fabricate Al 6113 composites. Ultrasonic- assisted stir casting technique was employed to prepare composites. FA particles with different weight proportions (3, 6 and 9 wt.%) are reinforced to prepare the composites and examine their properties (micro-hardness, compressive strength and wear rate). Furthermore, properties are also examined for the prepared as-cast composites subjected to heat treatment conditions. Microstructural analysis confirms, 6% FA particles are fairly and evenly distributed in Al6113 matrix material resulted in best properties. Al6113 with 6% fly ash particles improves 8.68% hardness and 61.6% compression strength of the compared to as-cast Al6113 specimen. Heat-treated composites showed a significant improvement from 73.7 to 82.5 HV for hardness, 75.61 to 130.7 MPa for compression strength, and decreased values in wear rate from 0.9233 to 0.4298 mm3/min, and Coefficient of Friction (CoF) from 0.648 to 0.319 compared to as-cast Al 6113 specimens. [ABSTRACT FROM AUTHOR]

Abstract Current work reports on the development of A357 alloy composite which is reinforced with dual size SiC particles by stir casting route. Influence of different weight fractions (3% coarse+ 3% fine, 4% coarse + 2% fine, and 2% coarse + 4% fine) of dual size SiC particles on mechanical properties and wear resistance of A357 composites is the focus of this work. Hardness and tensile properties were studied for dual size composites and then were compared with A357 alloy. Microstructural study, fractured surface and worn surface investigation were carried out using optical and scanning electron microscopes respectively. Microstructural analysis showed fairly uniform dispersion of dual size SiC particles in A357 matrix with good interfacial bonding. Compared to A357 alloy, the composites showed improvement in hardness, yield, and tensile strength. In particular, composite with 4 wt. % of fine and 2 wt. % of large SiC particles displayed the highest tensile strength while composite with 4 wt. % of large and 2 wt. % of fine SiC particles exhibited high hardness and wear resistance among A357 alloy and dual particle size composites. The strengthening mechanisms that contributed to improvement in strength values were effective load transfer and dislocation strengthening due to thermal mismatch. Highlights • Uniform dispersion of dual size SiC particles in A357 matrix. • Continuous interface and good bonding between A357 matrix and dual size SiC particles. • Significant improvement in hardness and mechanical properties of dual size composites compared to A357 alloy. • Improvement in wear resistance of dual size composites compared to A357 alloy. [ABSTRACT FROM AUTHOR]

The study of microstructures for the accurate control of material properties is of industrial relevance. Identification and characterization of microstructural properties by manual measurement are often slow, labour intensive, and have a lack of repeatability. In the present work, the intermetallic phase ratio and grain size in the microstructure of known Mg-Sn-Al alloys were measured by computer vision (CV) technology. New Mg (Magnesium) alloys with different alloying element contents were selected as the work materials. Mg alloys (Mg-Al-Sn) were produced using the hot-pressing powder metallurgy technique. The alloys were sintered at 620 °C under 50 MPa pressure in an argon gas atmosphere. Scanning electron microscopy (SEM) images were taken for all the fabricated alloys (three alloys: Mg-7Al-5Sn, Mg-8Al-5Sn, Mg-9Al-5Sn). From the SEM images, the grain size was counted manually and automatically with the application of CV technology. The obtained results were evaluated by correcting automated grain counting procedures with manual measurements. The accuracy of the automated counting technique for determining the grain count exceeded 92% compared to the manual counting procedure. In addition, ASTM (American Society for Testing and Materials) grain sizes were accurately calculated (approximately 99% accuracy) according to the determined grain counts in the SEM images. Hence, a successful approach was proposed by calculating the ASTM grain sizes of each alloy with respect to manual and automated counting methods. The intermetallic phases (Mg17Al12 and Mg2Sn) were also detected by theoretical calculations and automated measurements. The accuracy of automated measurements for Mg17Al12 and Mg2Sn intermetallic phases were over 95% and 97%, respectively. The proposed automatic image processing technique can be used as a tool to track and analyse the grain and intermetallic phases of the microstructure of other alloys such as AZ31 and AZ91 magnesium alloys, aluminium, titanium, and Co alloys. [ABSTRACT FROM AUTHOR]