scholarly journals Investigation of graphite effect on the mechanical and tribological properties of Al 7075-SiC-graphite hybrid metal matrix composites

2020 ◽  
Vol 37 (1−2) ◽  
Author(s):  
SRIDHAR ATLA ◽  
Prasanna Lakshmi Kaujala

The aluminium metal matrix composite reinforced with ceramic material of Silicon carbide (SiC) has good mechanical properties. However, aluminium based ceramic composites require improvements in their lubrication and tribological properties. In this study an attempt is made in the development of a new material through powder metallurgy technique by the addition of Graphite, which acts as a solid lubricant. This work investigated the influence of graphite on the wear behaviour of Al 7075/SiC /X wt.% graphite(X=0, 5 and 10) hybrid composite. The investigation reveals the effectiveness of incorporation of graphite in the composite for gaining wear reduction. The Al 7075 (aluminium alloy 7075) reinforced with SiC –graphite were investigated. The composites were fabricated using powder metallurgy route. The microstructures, material combination, wear and friction properties were analysed by scanning electron microscopy, XRD, and pin-on-disc wear tester. The newly developed aluminium composite has significant improvements in tribological properties with a combination of 5% Silicon carbide (SiC) and 5% Graphite. The test reveals that sliding distance of 1000 m and sliding speed of 1.5 m/s with applied load of 5 N result in minimum wear loss of 0.01062g and coefficient of friction as 0.1278.

The metal matrix composite strengthened with ceramic material of carbide (SiC) has smart mechanical characteristics. Metal-based composites, however, demand progress in their friction and tribological characteristics. In this work-study an effort is made to design a completely new material through the method of metallurgy by adding graphite, which acts as a solid lubricant. This study explored the effect of graphite on the tribological behaviour of hybrid composite Al 7075/5 wt. % SiC / X wt. % graphite (X=10, 5 and 0). The research confirms the performance of wear properties by incorporating graphite into the composite. The sic-graphite reinforced Al 7075 (aluminium alloy 7075) was studied. Metallurgy route was used to prepare the composites. Microstructures, the mixture of materials, wear and wear resistance properties were analyzed by optical micro cope and scanning electron microscope, XRD, and pin-on-disc apparatus. The freshly developed metal composite has significant improvement in tribological properties with a mixture 5% silicon carbide (SiC) and 5% graphite. The experimental investigations confirm that a sliding distance of one thousand meters and a sliding velocity of 1.5 m / s with an applied load of 5 N leads to minimum wear loss of 0.01062g and coefficient of friction as 0.1278


An attempt is made to find the mechanical and tribological properties of Al6061/Gr metal matrix composites (MMC) produced using stir casting method. It is important to note that the certain components require high hardness and wear resistance to fulfil the functional requirements, the said properties of the MMCs influenced largely on the condition with which they are produced or treated. Therefore, in the present paper the composites are tested in two stages that is before T6 heat treatment and after T6 heat treatment respectively. The composites are made with Al6061 alloy as matrix and graphite with 3%, 6%, 9% and 12% by wt is considered as reinforcement. Once the composites are prepared, they are examined for their microstructural, mechanical, and tribological properties. Further, a response surface methodology (RSM) has been used to model the wear loss and coefficient of friction for both before and after T6 heat treatment of MMCs. The non-linear regression model obtained is validated both statistically and with the help of experimental test cases. The evidence of wear phenomenon has been observed with the help of Scanning Electron Microscopy (SEM). Further, fuzzy grey relational Technique has been used to determine the multi performance index for the dry sliding wear and friction phenomenon of the developed composite.


2020 ◽  
Vol 22 (1) ◽  
pp. 65-76 ◽  
Author(s):  
M. Meignanamoorthy ◽  
M. Ravichandran

AbstractPowder Metallurgy (P/M) is playing a vital role to synthesize variety of materials in the field of aerospace, automobile, ordnance, petroleum and petrochemical industries. P/M is an outstanding process to produce components with good mechanical and tribological properties such as strength, hardness, impact resistance and wear resistance. Recently metal matrix composites (MMC) replace conventional alloys because of their extraordinary characteristics. Currently Aluminium, Copper, Magnesium, Titanium and Iron have been used as matrix materials and materials like TiC, SiC, B4C, WC, Cr3C, TiO2, ZrO2, Gr, MoS2, and Si3N4 have been used as reinforcements to synthesize metal matrix composites. When compare P/M with other manufacturing methods, it offers ordered microstructure with improved physical, mechanical and tribological properties. From these, powder metallurgy could be commented as an extremely active and cost-effective method when compare with other process. This paper explains the selection suitable process parameters for synthesize MMCs using P/M technique. This paper made an attempt to present the mechanical and tribological properties of various composites fabricated through powder metallurgy technique.


Author(s):  
S Rambabu ◽  
N Ramesh Babu

This article covers the efforts on characterising ice-bonded abrasive polishing tool in terms of the mechanical and tribological properties such as hardness, coefficient of friction, and wear rate. These studies were attempted on the tools prepared at different temperatures ranging from −10 °C to 0 °C with a view to identify the condition suitable to prepare ice-bonded abrasive polishing tool for effective polishing of Ti–6Al–4V alloy specimen. It also presents the methods adopted to determine various properties of ice-bonded abrasive polishing tool. Hardness was estimated from the measured penetration depth of cone shape indenter into the tool, coefficient of friction was determined from the change in power drawn by the motor rotating the tool mould, and wear behaviour of tool was assessed from the melting rate of the tool determined from the change in height of ice-bonded abrasive polishing tool at different stages of polishing. From the results of this study, it is clear that ice-bonded abrasive polishing tool prepared at −4 °C has possessed sufficient hardness, coefficient of friction, and reasonable wear rate suitable for polishing of Ti–6Al–4V specimens. This article also covers the details of low-temperature coolant supply unit developed to prepare the ice-bonded abrasive polishing tool at any desired temperature between 0 °C and −40 °C and thus to maintain it for a long time. Polishing studies with such ice-bonded abrasive polishing tool showed 72% improvement in finish after 90 min of polishing of Ti–6Al–4V specimen with tool, prepared at −4 °C.


2015 ◽  
Vol 766-767 ◽  
pp. 269-275 ◽  
Author(s):  
G. Saravanan ◽  
K. Shanmugasundaram ◽  
M. Prakash ◽  
A. Velayudham

The tribological behaviour of hybrid aluminium matrix composites (AMCs) A356 reinforced with SiC , Gr and Tin particulate, fabricated by powder metallurgy route. In this experimental study, the mechanical and tribological properties are investigated. The results show that addition of more reinforcements reduce the hardness and also increase the wear rate of the composites. The addition of Gr beyond certain limit will decrease hardness and that of SiC will increase brittleness. In the hybrid composite with 15% weight SiC and 5% weight Gr reinforcement results show that great improvement under tribological condition. The wear loss of the hybrid composites decreased with increasing applied load and sliding distance. The SEM analysis shows the wear tracks results of the composite materials.


Sign in / Sign up

Export Citation Format

Share Document