Effect of Reinforcement and Tribological Behaviour of AA 7068 Hybrid Composites Manufactured through Powder Metallurgy Techniques

2017 ◽  
Vol 867 ◽  
pp. 19-28 ◽  
Author(s):  
J. Lakshmipathy ◽  
Subburaj Rajesh Kannan ◽  
K. Manisekar ◽  
S. Vinoth Kumar

In this article, an attempt was made to study the mechanical behaviour of AA7068 - 6 vol. % of MoS2 - X vol. % of WC (X = 0, 5, 10 and 15) hybrid aluminium composites produced by blend–press–sinter methodology. Compacted Powders (700MPa) were sintered at different temperatures (450 0c, 500 0c and 550 0c ) in order to find the influence of sintering temperature on mechanical properties and tribological behavior of AA7068 hybrid composites.The sintered samples have been characterized by x-ray diffraction (XRD) method for identification of phases and also to investigate the phase changes. The change in density, hardness and porosity values of composites were reported. The composite with 15 vol. % of tungsten carbide and 6 vol. % of MoS2 showed the highest hardness and density at the sintering temperature range of 550 0c. Pin-on-disc type apparatus was used for determining the wear loss occurring at different conditions. The hybridization of the two reinforcements enhanced the wear resistance of the composites, especially under high applied load, sliding distance and sliding speeds. Due to this, the hybrid aluminium composites can be considered as an outstanding material where high strength and wear-resistant components are of major importance, predominantly in the aerospace and automotive engineering sectors. The morphology of the wear debris and the worn out surfaces were analyzed to understand the wear mechanisms.

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.


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


Electroless nickel-boron binary coatings were obtained with various bath compositions to investigate the effect of bath parameters on tribological and mechanical behaviours of the coating. Characterisation of the coating for surface morphology and phase structure is done using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD), respectively, whereas tribological behaviour of coatings is evaluated on a pin-on-disc tribo-tester. Elastic modulus and surface hardness of coatings have been obtained using nano-indentation technique, while the scratch behaviour of the coatings has been determined using micro-scratch test. Corrosion resistance of coatings is also determined. It is observed that surface roughness of the coatings increased with increase in sodium borohydride concentration but decreased slightly with increase in nickel chloride concentration. Friction and wear characteristics are found to increase with surface roughness which occurs due to increased boron content. Surface hardness and scratch hardness are also seen to vary with coating bath parameters.


2015 ◽  
Vol 75 (7) ◽  
Author(s):  
Amir Arifin ◽  
Abu Bakar Sulong ◽  
Norhamidi Muhamad ◽  
Junaidi Syarif

Hydroxyapatite (HA) has been widely used in biomedical applications due to its excellent biocompatibility. However, Hydroxyapatite possesses poor mechanical properties and only tolerate limited loads for implants. Titanium is well-known materials applied in implant that has advantage in mechanical properties but poor in biocompatibility. The combination of the Titanium alloy and HA is expected to produce bio-implants with good in term of mechanical properties and biocompatabilty. In this work, interaction and mechanical properties of HA/Ti6Al4V was analyzed. The physical and mechanical properties of HA/Ti6Al4V composite powder obtained from compaction (powder metallurgy) of 60 wt.% Ti6Al4V and 40 wt.% HA and sintering at different temperatures in air were investigated in this study. Interactions of the mixed powders were investigated using X-ray diffraction. The hardness and density of the HA/Ti6Al4V composites were also measured. Based on the results of XRD analysis, the oxidation of Ti began at 700 °C. At 1000 °C, two phases were formed (i.e., TiO2 and CaTiO3). The results showed that the hardness HA/Ti6Al4V composites increased by 221.6% with increasing sintering temperature from 700oC to 1000oC. In contrast, the density of the composites decreased by 1.9% with increasing sintering temperature. 


2013 ◽  
Vol 22 ◽  
pp. 501-510 ◽  
Author(s):  
S. K. TAK ◽  
M. S. SHEKHWAT ◽  
R. MANGAL

ZnO powder was synthesized by solid state reaction method. The synthesized powder was granulated and pressed using uni-axial press for preparing the pallets. The prepared pellets were sintered in conventional furnace at different temperatures (900-1300° C). The phase study was done by powder X-ray diffraction and it was found that the there is no other phase present in the synthesized material but the peak intensity is increasing with temperature. The crystallite size of the synthesized ZnO powder was found to be increase with temperature. The effect of sintering on grain growth is investigated by scanning electron microscopy (SEM). SEM revels that the average grain size is increases with increase in sintering temperature. AC impedance of these samples was decreased markedly with increased sintering temperature. In present work the effect of sintering temperatures and hold time on micro structural and electrical properties of ZnO ceramics is carried out.


2008 ◽  
Vol 1128 ◽  
Author(s):  
Mira Sakaliyska ◽  
Sergio Scudino ◽  
Hoang Viet Nguyen ◽  
Kumar Babu Surreddi ◽  
Birgit Bartusch ◽  
...  

AbstractNanostructured Al-Mg bulk samples with compositions in the range of 10 – 40 at.% Mg have been produced by consolidation of mechanical alloyed powders. Powders with composition Al90Mg10 and Al80Mg20 were consolidated into highly dense specimens by hot extrusion. Room temperature compression tests for the Al90Mg10 specimen reveal interesting mechanical properties, namely, a high strength of 630 MPa combined with a plastic strain of about 4 %. The increase of the Mg content to 20 at.% increases the strength by about 100 MPa but it suppresses plastic deformation. The Al60Mg40 powder was consolidated at different temperatures by spark plasma sintering and the effect of the sintering temperature on microstructure, density and hardness have been studied. The results reveal that both density and hardness of the consolidated samples increase with increasing sintering temperature, while retaining a nanocrystalline structure. These results indicate that powder metallurgy is a suitable processing route for the production of nanocrystalline Al-Mg alloys with promising mechanical properties.


Author(s):  
Nazia Khatun ◽  
Mohammad Sajjad Hossain ◽  
Most. Hosney Ara Begum ◽  
Suravi Islam ◽  
Nazmul Islam Tanvir ◽  
...  

Spinel ferrite Ni[Formula: see text]Mn[Formula: see text]Zn[Formula: see text]Fe2O4 was prepared by a conventional ceramic process followed by sintering at three different temperatures (1050[Formula: see text]C, 1100[Formula: see text]C and 1150[Formula: see text]C). X-ray diffraction (XRD) investigations stated the single-phase cubic spinel structure and the FTIR spectra revealed two prominent bands within the wavenumber region from 600 cm[Formula: see text] to 400 cm[Formula: see text]. Surface morphology showed highly crystalline grain development with sizes ranging from 0.27 [Formula: see text]m to 0.88 [Formula: see text]m. The magnetic hysteresis curve at ambient temperature revealed a significant effect of sintering temperature on both coercivity ([Formula: see text] and saturation magnetization ([Formula: see text]. Temperature caused a decrease in DC electrical resistivity, while the electron transport increased, suggesting the semiconducting nature of all samples and that they well followed the Arrhenius law from which their activation energies were determined. The values of Curie temperature ([Formula: see text] and activation energy were influenced by the sintering temperature. Frequency-dependent dielectric behavior (100 Hz–1 MHz) was also analyzed, which may be interpreted by the Maxwell–Wagner-type polarization. The UV–vis–NIR reflectance curve was analyzed to calculate the bandgap of ferrites, which showed a decreasing trend with increasing sintering temperature.


Author(s):  
S. Rajeshkannan ◽  
I. Manikandan ◽  
M. Vigneshkumar

Semiconductors like ZnS, TiO2 and BaTiO3 were reinforced with Al-Al2O3 Metal Matrix Composites (MMCs) and were made through powder metallurgy in order to have high strength, high hardness and good thermal conductivity compared with conventional materials. Three MMC of test specimens were prepared with varying reinforcement ratio Al-Al2O3-ZnS(94-5-1), Al-Al2O3-TiO2(94-5-1), Al-Al2O3-BaTiO3(94-5-1) percentage by weight respectively. The hardness test has been made by using Brinell hardness testing instrument. Hardness test revealed that the addition of reinforcement TiO2, BaTiO3 increases the hardness value. However, the addition of ZnS to the Al-Al2O3 MMCs showed decrease in the hardness value. The crystal structure of the 3 composites were examined through X-Ray Diffraction (XRD) peaks.


Author(s):  
Jaswinder Singh ◽  
Amit Chauhan

In this study, frictional and wear behavior of Al2024/SiC/red mud hybrid composites processed by stir casting route has been investigated under dry sliding conditions. Further, influence of parameters, namely red mud fraction (5–20 wt%) and particle size (37–125 µm), applied load (10–40 N), sliding distance (3000–6000 m), sliding velocity (0.5–2.0 m/s), and their interaction terms on multiresponse characteristics has been examined by employing Taguchi's approach. The wear behavior of hybrid Al composites has been investigated using pin-on-disc apparatus at room temperature and optimization of parameters has been carried by statistical analysis. The adequacy of the developed model has been checked by conducting confirmation experiment and studying the worn surface morphology. The analysis of variance indicates that sliding distance has highest influence (with a contribution of 19.74%) on the wear loss characteristics, while applied load has a maximum contribution of 38.86% in the friction coefficient of the hybrid composites. It has also been revealed that the wear resistance of the hybrid composites is improved with an increase in red mud fraction and decrease in the magnitude of applied load and sliding distance. The morphology of worn surfaces shows that ploughing and abrasion of the wear surface is considerably increased with an increase in the magnitude of wear parameters. But, an increase in red mud fraction reduces the plastic deformation (delamination) of the wear surface since it favors formation of a protective layer between the sliding surfaces. The results of the confirmation experiment indicate that wear loss and friction coefficient of the developed composites have been reduced by 400 and 51%, respectively, in comparison to unreinforced alloy under optimized conditions. The errors in the measurements of the wear loss and friction coefficient have been found to be 4.26 and 2.63%, respectively.


2019 ◽  
Vol 801 ◽  
pp. 89-94
Author(s):  
Sutanu Samanta ◽  
Thingujam Jackson Singh

The present work aims to experimentally investigate the effect of Kevlar fiber hybridization on dry sliding friction and wear behaviour of bamboo fiber reinforced laminated epoxy composite. Monolithic bamboo laminated composite and different bamboo/Kevlar inter-ply laminated hybrid composites with variation in number of both the laminas were developed in house by hand layup technique. Pin-on-disc experiment was employed to determine its tribological performance. The wear mass loss, specific wear rate and co-efficient of friction of the developed composites, when slide against a rotating disc, were determined and analyzed. The wear mechanisms were studied from the microstructure. From the results, it is observed that, wear loss and co-efficient of friction values were increased with the increase in number of Kevlar laminas.


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