Experimental Investigations on the Wear Behaviour of Eutectic Al-7075/CNT/Graphite Composites Manufactured by a Combination of Two-Stage Stir and Squeeze Casting Techniques (original) (raw)
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A study on wear behaviour of Al/6101/graphite composites
Journal of Asian Ceramic Societies, 2017
The current research work scrutinizes aluminium alloy 6101-graphite composites for their mechanical and tribological behaviour in dry sliding environments. The orthodox liquid casting technique had been used for the manufacturing of composite materials and imperilled to T6 heat treatment. The content of reinforcement particles was taken as 0, 4, 8, 12 and 16 wt.% of graphite to ascertain it is prospective as self-lubricating reinforcement in sliding wear environments. Hardness, tensile strength and flexural strength of cast Al6101 metal matrix and manufactured composites were evaluated. Hardness, tensile strength and flexural strength decreases with increasing volume fraction of graphite reinforcement as compared to cast Al6101 metal matrix. Wear tests were performed on pin on disc apparatus to assess the tribological behaviour of composites and to determine the optimum volume fraction of graphite for its minimum wear rate. Wear rate reduces with increase in graphite volume fraction and minimum wear rate was attained at 4 wt.% graphite. The wear was found to decrease with increase in sliding distance. The average coefficient of friction also reduces with graphite addition and its minimum value was found to be at 4 wt.% graphite. The worn surfaces of wear specimens were studied through scanning electron microscopy. The occurrence of 4 wt.% of graphite reinforcement in the composites can reveal loftier wear possessions as compared to cast Al6101 metal matrix.
Wear, 2009
The influence of graphite content on the dry sliding and oil impregnated sliding wear characteristics of sintered aluminum 2024 alloy-graphite (Al/Gr) composite materials has been assessed using a pin-ondisc wear test. The composites with 5-20 wt.% flake graphite particles were processed by in situ powder metallurgy technique. For comparison, compacts of the base alloy were made under the same consolidation processing applied for Al/Gr composites. The hardness of the sintered materials was measured using Brinell hardness tester and their bending strength was measured by three-point bending tests. Scanning electron microscopy (SEM) was used to analyze the debris, wear surfaces and fracture surfaces of samples. It was found that an increase in graphite content reduced the coefficient of friction for both dry and oil impregnated sliding, but this effect was more pronounced in dry sliding. Hardness and fracture toughness of composites decreased with increasing graphite content. In dry sliding, a marked transition from mild to severe wear was identified for the base alloy and composites. The transition load increased with graphite content due to the increased amount of released graphite detected on the wear surfaces. The wear rates for both dry and oil impregnated sliding were dependent upon graphite content in the alloy. In both cases, Al/Gr composites containing 5 wt.% graphite exhibited superior wear properties over the base alloy, whereas at higher graphite addition levels a complete reversal in the wear behavior was observed. The wear rate of the oil impregnated Al/Gr composites containing 10 wt.% or more graphite particles were higher than that of the base alloy. These observations were rationalized in terms of the graphite content in the Al/Gr composites which resulted in the variations of the mechanical properties together with formation and retention of the solid lubricating film on the dry and/or oil impregnated sliding surfaces.
Wear Characteristics of Al 6061 reinforced with graphite under different loads and speeds
This work investigates Al 6061 alloy with graphite particle impregnated metal matrix composites under dry sliding conditions. The conventional casting techniques were used for preparing the composite material. Experiments were conducted under dry sliding conditions for determining the wear behavior of Al 6061 alloy-Graphite composite material with varying wt % graphite content under different sliding speeds and at different loads. Sliding distance of 250m was commonly used for the wear test. A pin on disc machine was used for conducting the wear test. The test was conducted under atmospheric conditions. Wear rate decreases with increased sliding speed and increases with increasing load. Worn surfaces of the composites were examined through scanning electron microscope. The wear loss of the composite material with 5Wt % graphite was found to be minimum with respect to sliding speeds and loads.
An Investigation on Wear Behavior of Graphite Reinforced Aluminum Metal Matrix Composites
2018
The present work investigates the 6061Al alloy – Graphite composite with graphite particle dispersions upto 9% to identify its potential to act as a self lubricating material at an optimum level of graphite. The required specimens are prepared using stir casting method with graphite proportions ranging from 3 to 9% by weight. Experiments were carried out to evaluate the tribological behavior of the composite material with varying graphite content in terms of coefficient of friction and wear rate. Under dry sliding conditions, effects of the sliding distance and sliding speed have also been studied. Under dry sliding conditions, minimum coefficient of friction and wear rate has been observed for 9% graphite content. Consequently 6061Al-graphite showed its capability to act adequately as a self lubricating material. Keywords—Aluminium-graphite MMC, Wear behavior, 6061Al-Graphite particulates, Coefficient of Friction
International Journal of Scientific Research in Science and Technology, 2019
This research work investigated the in?uence of graphite powder on the wear behavior of Al 7075/Graphite Powder (Gr)/Bagasse ash (BA) hybrid composite. The investigation reveals the effectiveness of incorporation of graphite powder in the composite for gaining wear reduction. The Al 7075 (Aluminium alloy 7075) reinforced with graphite powder and Bagasse ash were investigated. The conventional liquid casting technique was used for the fabrication of composite material and subjected to T6 heat treatment. The reinforcement content was chosen as 1, 3, and 5wt. % of graphite powder to identify its potential for self-lubricating property under dry sliding conditions. Hybrid composite is processed at 1wt% of Gr with 2, 4 and 6wt% of BA. The effect of load on dry sliding wear rate and coefficient of friction performance of Al 7075 casting alloy and its composites was evaluated by using a pin-on-disc with two different loads with constant speed at room temperature. Wear tests were conducted by using pin on disc apparatus to evaluate the tribological behaviour of the composite and to determine the optimum content of graphite powder for its minimum wear rate. The wear rate decreases with addition of graphite powder content and reaches its minimum at 5wt. % graphite. The coefficient of friction decreases with addition of graphite content and was found to be minimum at wt. 5% graphite. The wear properties of the hybrid composites containing graphite exhibited the superior wear-resistance properties.
Aluminum matrix composites (AMCs) are candidate materials for aerospace and automotive industry owing to their large elastic modulus, improved strength and low wear rate. A simple method for fabrication of Al7075-graphite composites produced by mechanical alloying (MI) and hot extrusion is described in this paper. Effects of milling time (0-10 h) and graphite concentration (0-1.5 wt.%) on friction, hardness and wear resistance of the AMC were investigated. Wear resistance was determined by the pinon-disk wear method using 20 and 40 N normal loads at a 0.367 m/s sliding velocity. The worn surfaces were examined by scanning electron microscopy (SEM) to identify distinct topographical features for elucidation of the prevailing wear mechanisms. Experimental results indicated considerable improvement in AMC hardness and wear resistance by adding 1.5% G (wt.) and 10 h of milling, showing homogenous distribution of the reinforcement particles in the Al-base metal-matrix composite. It was found that abrasion is the dominant wear mechanism in all extruded composites, whilst a combination of adhesion and delamination seems to be the governing mechanism for the 7075 aluminum alloy.
Effect of Graphite Content on Tribological behaviour of Aluminium alloy - Graphite Composite
Euro Journals
An attempt has been made to study the influence of operating parameters such as applied load, sliding speed, percentage of reinforcement content and sliding distance on the dry sliding wear of 6061 aluminium with SiC and B4C particulate reinforced composite. The particulate reinforced 6061 aluminium alloy with a constant weight percentage of B4C particulate and varying range of SiC particulate is produced by stir casting technique. In order to achieve good binding between the matrix and particulates, 1% of magnesium alloy is added. Under dry condition the hybrid composite performances were investigated by pinon-disc with varying load conditions. The uniform distribution of particulates reinforced in the matrix was examined with the help of Optical-Microscope. The wear surfaces of the specimen at room temperature were examined before and after the wear test by using Scanning Electron Microscope (SEM). The hardness of the specimen at room temperature was also measured before the wear test by Rockwell hardness test machine. As the volume fraction of SiC and B4C reinforcement increases, the magnitude of hardness also increases. This investigation overviews that 6061 hybrid composite with high hardness can replace the conventional material used in automobile components for better performance and longer life.
Al/Graphene/CNT hybrid composites: Hardness and sliding wear studies
FME Transactions, 2021
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. T...
Advances in Materials Science and Engineering
The current paper aims to study wear behaviour of AA7075 reinforced with different weight percentage of nano-TiC and graphite particles under dry sliding condition. TiC particles are taken in different weight percentages (5%, 10%, and 15%), and graphite was chosen as (3%, 4%, and 5%) along with three different levels of sliding speed, applied load, and sliding velocity. The fabrication was conducted using stir casting equipment, and the experiments were done using Taguchi’s L27 orthogonal array. The Taguchi and ANOVA results applied load and percentage of TiC are the most influencing parameters which influences wear loss and friction coefficient