Influence of MoS2 on Microstructure and Mechanical Behaviours of Al6061-Al2O3 Hybrid Composite

2015 ◽  
Vol 813-814 ◽  
pp. 62-66
Author(s):  
S. Maivizhi Selvi ◽  
A. Saravana Kumar ◽  
G. Isaac Daniel Raj ◽  
N. Keerthana ◽  
G.D. Madhanagopal ◽  
...  

In this investigation, the influence of MoS2 on the mechanical properties of Al6061-Al2O3hybrid composites was studied. The composites of Al6061 alloy, AA 6061-6% Al2O3 and Al6061-6% Al2O3-2% MoS2 were manufactured using Stir casting method. These samples were examinedusing optical microscope for the dispersion of reinforcement (Al2O3 ) and solid lubricant (MoS2).The micro structure revealed that there were even distribution of the additives in the Al6061 matrix.The presence of these particles improved the mechanical properties of the composites. For these compositions flexural strength was found using 3 point bending test and impact strength was found using Charpy test. It was observed that the hardness, toughness and flexural strength values increases with the addition of Al2O3 and decreases with the addition of MoS2 to the second composition.

2018 ◽  
Vol 929 ◽  
pp. 86-92
Author(s):  
Donanta Dhaneswara ◽  
Luthfi Noviardi Andani ◽  
Nofrijon Sofyan ◽  
Anne Zulfia Syahrial

Nano SiC-reinforced aluminumA356 (A356/SiC) has been successfully fabricated using stir casting method. The specimen was fabricated by adding various Nano SiC concentrations, i.e. 0, 0.10, 0.15, 0.20, 0.25, and 0.30 wt.%, at fix 1 wt.% magnesium into aluminum A356 melt. After stirring at certain time, the mixture was poured into the mold that has been preheated at 350oC for 5 minutes. The mechanical properties were characterized using tensile, hardness, and wear testing, where as the microstructural observation was performed using an optical microscope. The results show that the mechanical properties were optimum at 0.25 wt.% Nano SiC with a strength of 175.57 MPa (21.87%), toughness of 0.0287 Joules/mm3(14.8%), hardness of 56.54 HBN (50%), and wear resistance of 1.75 x 10-5 mm3/mm (21.13%). These results indicate that the fabrication approach was successful in producing cast MMCs samples and the use of Nano SiC and Magnesium as a wetting agent with continuous stirring were found to promote the wettability of SiC and A356 matrix alloy and thus result in reasonable mechanical properties of the composite.


2013 ◽  
Vol 544 ◽  
pp. 271-275
Author(s):  
Hai Ttao Wang ◽  
Yi Hong Liu ◽  
Yong Wang ◽  
Hui Juan Chen ◽  
Yan Qiu ◽  
...  

The conventional method of producing porcelain standard disc specimens is based on the dental lab method for bilayer ceramic crowns, in order to reflect the clinical using condition. However heavy task is facing to the researchers, which is producing a large amount of the specimens efficiently. The press molding method is used to produce dental porcelain disc specimens in this study. Then, the basic mechanical properties of two groups of porcelain specimens were tested respectively, comparing with handmade and press molding method. The density was measured by Archimedes' method, the flexural strength was tested by biaxial bending test, and the hardness was checked by microhardness tester. The micro features of the specimens before and after bending test were observed under optical microscope and SEM. The results showed that there was no significant difference in the flexural strength, microhardness and density of porcelain discs made by two methods. Air pores were found in all specimens with size between 5-50 micrometers. The size and distribution of pores in the specimens by press molding method are more homogeneous than handmade method. Producing dental porcelain discs for laboratory testing specimens by press molding method was much easy than handmade method. Furthermore, the mechanical properties and microstructures of the specimens made by handmade method and press molding method were almost same.


2015 ◽  
Vol 813-814 ◽  
pp. 90-94
Author(s):  
A. Saravana Kumar ◽  
P. Sasikumar

This work investigated the influence of multi axial forging (MAF) on the microstructure and mechanical properties of AA6063/Al2O3/Gr hybrid composite. It reveals that the effectiveness of forged composite exhibited better mechanical properties. The AA6063 reinforced with Al2O3 and 1 wt. % graphite (Gr) hybrid composite were fabricated using stir casting technique. The microstructure of the hybrid composite was examined using optical microscope. The mechanical properties in terms of hardness, flexural strength and compression strength were investigated. It was observed that the mechanical properties of multi axially forged hybrid composite exhibited around 15, 7 and 5 times higher than unreinforced alloy, as-casted hybrid composite and as-hardened hybrid composite. These results revealed that the multi axially forged hybrid composite would be well suited for high strength applications.


2018 ◽  
Vol 16 (1) ◽  
pp. 726-731 ◽  
Author(s):  
Tennur Gülşen Ünal ◽  
Ege Anıl Diler

AbstractThe effects of micro and nano sized reinforcement particles on microstructure and mechanical properties of aluminium alloy-based metal matrix composites were investigated in this study. AlSi9Cu3 alloy was reinforced with micro and nano sized ceramic reinforcement particles at different weight fractions by using a stir casting method. The mechanical tests (hardness, three point bending) were performed to determine the mechanical properties of AlSi9Cu3 alloy-based microcomposites (AMMCs) and nanocomposites (AMMNCs). The experimental results have shown that the size and weight fraction of reinforcement particles have a strong influence on the microstructure and the mechanical properties of AlSi9Cu3 alloy-based microcomposites and nanocomposites. The relative densities of all AMMC and AMMNC samples are lower than unreinforced AlSi9Cu3 alloy due to porosity formation with the increase of weight fraction of reinforcement particles. As weight fraction increases, hardness values of AMMCs and AMMNCs increase. Maximum flexural strength can be obtained at 3.5wt.% for the AMMC sample with microsized Al2O3 particles and at 2wt.% for the AMMNC sample with nano-sized Al2O3 particles. After the weight fractions exceed these values, flexural strengths of both AMMCs and AMMNCs decrease due to clustering of Al2O3 particles.


2013 ◽  
Vol 592-593 ◽  
pp. 614-617 ◽  
Author(s):  
Konstantinos Anthymidis ◽  
Kostas David ◽  
Pavlos Agrianidis ◽  
Afroditi Trakali

It is well known that the addition of ceramic phases in an alloy e.g. aluminum, in form of fibers or particles influences its mechanical properties. This leads to a new generation of materials, which are called metal matrix composites (MMCs). They have found a lot of application during the last twenty-five years due to their low density, high strength and toughness, good fatigue and wear resistance. Aluminum matrix composites reinforced by ceramic particles are well known for their good thermophysical and mechanical properties. As a result, during the last years, there has been a considerable interest in using aluminum metal matrix composites in the automobile industry. Automobile industry use aluminum alloy matrix composites reinforced with SiC or Al2O3 particles for the production of pistons, brake rotors, calipers and liners. However, no reference could be cited in the international literature concerning aluminum reinforced with TiB particles and Fe and Cr, although these composites are very promising for improving the mechanical properties of this metal without significantly alter its corrosion behavior. Several processing techniques have been developed for the production of reinforced aluminum alloys. This paper is concerned with the study of TiB, Fe and Cr reinforced aluminum produced by the stir-casting method.


Author(s):  
Amneesh Singla ◽  
Rajnish Garg ◽  
Mukesh Saxena

A 356 alloy reinforced with insitu V2O5 particles by using stir casting technique. The composites were produced by the addition of oxide particles in different weight percentage. The effect of oxide powder addition on microstructure and mechanical properties of produced composites were investigated. The effect of heat treatment on microstructure and mechanical properties were investigated by optical microscope, Microhardness tester and tension test. A significant improvement in hardness and tensile strength was revealed in the produced composite as compared to the base alloy. With the addition of oxide particles, the shape and size of eutectic Si changed which in turn affects the properties. It was observed that 2h solutionizing followed by the artificial aging was sufficient to make the structure homogenize and to produce the hardening precipitates. The improvement in the mechanical properties has been observed due to the age hardening precipitates in addition with refinement of insitu V2O5 particles.


2016 ◽  
Vol 27 (6) ◽  
pp. 670-674 ◽  
Author(s):  
Veridiana Resende Novais ◽  
Priscilla Barbosa Ferreira Soares ◽  
Carlla Martins Guimarães ◽  
Laís Rani Sales Oliveira Schliebe ◽  
Stella Sueli Lourenço Braga ◽  
...  

Abstract This study evaluated the effect of gamma radiation and endodontic treatment on the microhardness and flexural strength of human and bovine root dentin. Forty single-rooted human teeth and forty bovine incisor teeth were collected, cleaned and stored in distilled water at 4 °C. The human and bovine teeth were divided into 4 groups (n=10) resulting from the combination of two study factors: first, regarding the endodontic treatment in 2 levels: with or without endodontic treatment; and second, radiotherapy in two levels: with or without radiotherapy by 60 Gy of Co-60 gamma radiation fractioned into 2 Gy daily doses five days per week. Each tooth was longitudinally sectioned in two parts; one-half was used for the three-point bending test and the other for the Knoop hardness test (KHN). Data were analyzed by 3-way ANOVA and Tukey HSD test (α=0.05). No significant difference was found for flexural strength values. The human dentin had significantly higher KHN than the bovine. The endodontic treatment and radiotherapy resulted in significantly lower KHN irrespective of tooth origin. The results indicated that the radiotherapy had deleterious effects on the microhardness of human and bovine dentin and this effect is increased by the interaction with endodontic therapy. The endodontic treatment adds additional negative effect on the mechanical properties of radiated tooth dentin; the restorative protocols should be designed taking into account this effect.


2013 ◽  
Vol 845 ◽  
pp. 398-402 ◽  
Author(s):  
Chinnasamy Muthazhagan ◽  
A. Gnanavelbabu ◽  
G.B. Bhaskar ◽  
K. Rajkumar

This paper deals with the mechanical properties in conventional heat treatment of Al (6061)-B4C-Graphite. Aluminium Metal Matrix Composites (MMC) is fabricated through two step stir casting method. The composites were fabricated with various volume percentage levels as Aluminium reinforced with (5, 10 &15%) Boron Carbide and (5,10 & 15%) of Graphite. Fabricated composites were subjected to conventional heat treatment for enhancing the mechanical properties. Influences of Graphite reinforcement on mechanical properties of Aluminum-Boron carbide composites were analyzed. The microstructure studies were also carried out. It is observed that increasing the graphite content within the aluminum matrix results in significant decrease in ductility, hardness, ultimate tensile strength. The addition of boron carbide conversely increased the hardness of the composites.


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