Search

Graphene and carbon nanotubes are two carbon based materials known for their unique wear and friction properties. It would be quite interesting to understand the wear behavior of aluminium hybrid composites when these two nanosize reinforcements are incorporated into it. The hybrid composites with varying weight fractions of graphene (1, 2, 3 and 5 wt.%) and fixed CNT content of 2 wt.% were produced using powder metallurgy technique. The effect of varying graphene content on hardness and sliding wear of hybrid composites was studied. The wear tests were done as per ASTM G-99 standard with fixed sliding velocity (2 m/s) and sliding distance (1200 m) but varying applied load (10 - 30 N). Worn surface analysis was conducted using scanning electron microscope to arrive at wear mechanisms responsible for wear of aluminium and its hybrid composites. Increase in graphene content led to increase in bulk hardness with highest value of 61 RHN for hybrid composite with 3 wt.% graphene content. The wear rate of hybrid composites was found to be decreasing with enhancement in graphene content. Lower wear rate in hybrid composites was due to the formation of lubricating layer on the worn surface.

The cutting fluid's lubrication affects a workpiece's surface finish and cutting tool lifespan during turning. To optimize machine performance, appropriate lubrication is needed. Empirical experiments examined how machining factors affected a redesigned single-point cutting tool. Texturing the tool's rake surface without altering its physical qualities was achieved utilizing super-drilling and laser engraving technologies. The goal was to build a surface junction that would keep cutting fluid in contact with the tool longer, improving lubrication and cooling. Both standard and customized tools were used to compare cutting force, temperature, power usage, and surface polish. Magnified pictures from the scanning electron microscope were utilized to analyze tool wear in different places. The improved tool dramatically lowered mean cutting force, heat output, and power consumption in experiments. The textured tool produced continuous chips instead of discontinuous/burnt chips due to increased friction at the tool–chip interface. The updated tool improved lubrication and cooling with cutting fluid. [ABSTRACT FROM AUTHOR]

The current study examines the erosive behaviour of a 65% NiCrAlY + 35% TiO2 plasma-sprayed coating on titanium-15 substrate at various temperatures. X-ray diffraction and scanning electron microscopy were used to characterize the coating. We assessed the coating's porosity, microhardness, surface abrasiveness, and adhesive power. At impact angles of 30° and 90°, solid particle erosion studies were conducted at various temperatures of 300°C, 500°C, and 700°C. The Al2O3 erodent was used in the hot air jet erosion tester to conduct the testing. Using an optical profilometer, the erosion volume loss of substrates with and without coatings was measured. At the various test temperatures used, it was noted that the coating's erosion resistance was found to be higher than the substrate's. For both impact angles, of 30° and 90°, it was discovered that the coating's erosion resistance improved with temperature, going from 300°C to 700°C. It can be seen from the shape of the degraded coating surface that the coating exhibits ductile behavior as a whole. [ABSTRACT FROM AUTHOR]

The development of many engineered product applications for automobiles and aircraft parts has initiated the search for novel materials as alternatives to metal matrix composites (MMCs). Natural-fiber-reinforced polymer composites offer distinct advantages such as biodegradability, eco-friendliness, flexibility, low density, and higher specific strengths, etc. This study focuses on natural-fiber (hemp and banana)-fabric-reinforced polymer composites suitable for exterior-engineered parts. The hand lay-up process is used to fabricate these hybrid composites. Exterior-engineered products are highly susceptible to moisture, which can deteriorate their mechanical performances, including their tensile and flexural strength, thereby affecting the durability of the hybrid composites. Therefore, the hybrid composites are subjected to water absorption tests, where samples are immersed in distilled water for week-long intervals. After each interval, the water-absorbed specimens are tested for their tensile and flexural characteristics as per ASTM D-3039 and ASTM D-790, respectively. The moisture treatment had a notable impact on the composite materials, causing a slight decrease in the tensile strength by 2% due to the diminished lateral strength in the interlaminar fibers. Contrary to expectations, the flexural strength of the composites improved by 2.7% after the moisture treatment, highlighting the potential of the moisture treatment process to enhance the elastic properties of such composites. The dimensions of the specimens changed after the water immersion test, resulting in increased longitudinal and decreased lateral dimensions. The surface morphologies of the composite failure samples showed fiber delamination, fiber breakage, voids, and matrix fractures. [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]

Increased material demand in all sectors is primarily due to exponential growth in population to fulfill human needs and comforts. Recycling of collected aluminium beverage cans and Al 6061 alloy scraps from industries ensures significant advantages in terms of energy savings with reduced environmental problems in fabricating composite parts economically. The iron oxide (α-Fe2O3) nanoparticles are prepared by precipitation method using ferric chloride and ammonia as a precursor. The prepared nanoparticles were characterized by using Transmission Electron Microscope (TEM), XRay Diffraction (XRD) and Fourier Transform Infrared (FTIR). Stir cast processing route ensures uniform mix of reinforcement nanoparticles in matrix material. The prepared nanocomposites (matrix: Al Scrap (90% Scrap Al 6061 alloy + 10% Waste Al can); reinforcement (Fe2O3): 2%, 4% and 6% wt. of Al matrix) are mechanically characterized for hardness and tensile strengths. It was observed that, increased percent of Fe2O3 nanoparticles in the metal matrix nanocomposite (MMCs) resulted in significant increase in hardness and tensile strength values. Fractography analysis examined viz. scanning electron microscope (SEM) revealed a ductile failure for as-cast Al scrap followed by brittle failure in Al MMC's. [ABSTRACT FROM AUTHOR]

Copyright of FME Transactions is the property of University of Belgrade, Faculty of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)