scholarly journals Experimental studies of different quenching media on mechanical and wear behavior of Al7075/SiC/Al2O3 hybrid composites

2020 ◽  
Vol 15 (55) ◽  
pp. 20-31
Author(s):  
M. Ravikumar ◽  
H.N. Reddappa ◽  
R. Suresh ◽  
M. Sreenivasa Reddy

The effects of SiC-Al2O3 particle in the Al alloy on the mechanical and wear characteristics of stir-casted Composites have been reported. The Al7075 is reinforced with 2, 4, 6 and 8 wt. % of (SiC + Al2O3) to manufacture the hybrid composite. Ceramic particulates were added into Al alloy to achieve the low wear rate and improving mechanical properties. Hardening of casted specimens at 480ºC for the duration of 2 hrs and the specimens were quenched into two different quenching media (water and ice cubes). Finally, age-hardening were carried out at the temperature of 160ºC for the duration of 4 hrs and cooled at room temperature. The tensile strength, hardness and wear behaviour of MMCs are evaluated on the un-treated and heat treated composite. The tensile strength and hardness of MMCs increases by incorporating SiC-Al2O3 particulates. The wear behaviour of the MMCs containing SiC-Al2O3 particulates revealed the high wear-resistance. The heat-treatment had considerably improved the properties when compared to the un-heat treated composites. The composites with the highest tensile strength, hardness and enhanced wear resistance were found in the composites quenched in ice cubes. Worned surfaces of the composite specimens were studied by using SEM and XRD analysis

Author(s):  
Theerkka tharaisanan Rajamanickam ◽  
Kathiresan Marimuthu

Aluminium metal matrix composites (AMMC’s) have been widely used because of their superior properties like high strength to wear ratio, high wear resistance, and higher heat conduction rate. The additions of reinforcements in the form of discontinuous particles lead to an increase in the properties of Metal Matrix Composites (MMC). In this present work, the ALMMC composite was fabricated with the addition of discontinuous reinforcement particles of Zirconium Carbide (ZrC) and Boron Carbide (B4C). The mechanical properties such as tensile strength, hardness, and impact strength were tested as per the ASTM standards. The tribological properties were tested using a pin-on-disc setup under different loading conditions (10, 20, 30, 40 N). Moreover, the morphological characterization of ALMMC was carried out by using the Scanning Electron Microscope (SEM) analysis. Furthermore, the Differential Thermal Analysis (DTA) and Thermogravimetric Analysis (TGA) was accomplished to find the thermal stability of ALMMC. The findings show that the variations of reinforcement of ZrC added had given improved properties like hardness, tensile strength, impact strength and wear resistance.


2019 ◽  
Vol 13 (1) ◽  
pp. 4380-4389
Author(s):  
Gowrishankar M. C. ◽  
Sathyashankara Sharma ◽  
B. K. Pavan ◽  
Kamath Kiran ◽  
Kumar Rajendra ◽  
...  

Aluminium alloy matrix composites with Al2O3 reinforcements exhibit superior mechanical properties and utilize in several demanding fields’ viz., automobile, aerospace, defense, sports equipment, electronics and bio-medical. The present work emphasizes on improvement of microstructure and mechanical properties of age hardened graphite and alumina reinforced Al alloy matrix hybrid composites. Different composites with a constant carbon content of 1 weight % and 0, 2, 4 and 6 weight % Al2O3 as reinforcements are fabricated by using stir casting technic and tested for hardness, tensile and impact strength. Scanning electron microscopy (SEM) is performed to analyse the failure mode under tensile load. All the composites are subjected to age hardening treatment with solutionising temperature of 530oC and aging temperatures of 100 and 200oC. The peak hardness of the composites at two aging temperatures are noted. Tensile and impact tests are conducted for the peak aged specimens.  Results show substantial increase in the hardness of the age hardened specimens in the range of 34-44% in comparison with the as cast specimens. Result analysis shows increase in tensile strength (upto 40%) and decrease in impact resistance (upto 33%) with the increase in weight % of reinforcements. As the aging temperature increases a reduction in tensile strength and impact resistance is observed in each composites.


2015 ◽  
Vol 830-831 ◽  
pp. 358-361 ◽  
Author(s):  
D.G. Sondur ◽  
D.M. Goudar ◽  
D.G. Mallapur ◽  
G.B. Rudrakshi

In the present investigation, microstructural characteristics and dry sliding wear behaviour of T6 heat treated conventionally cast Al-25Mg2Si-2Cu alloy have been discussed. The as cast alloy was subjected to solutionizing at 500°C for 5h and isothermal aging treatment at 190°C for different aging times. The micro structural characterization was studied using Scanning Electron Microscope with EDS analysis. The microstructure of as cast alloy consists of intermetallics of coarse block like sharp edged β-(Mg2Si), θ-(Al2Cu) and Q-(Al-Mg-Cu-Si) in the form of Chinese scripts and needles distributed randomly in the Al-matrix. The microstructure of heat treated alloy shows spheroidization of β phase and fine precipitation of θ-(Al2Cu) and Q phases. The dry sliding wear test was carried out using pin-on-disc machine. Age hardened alloy exhibits high wear resistance and minimum coefficient of friction over the entire range of applied loads and sliding velocities. Furthermore, high wear resistance was observed in the under aged condition compared to over ageing conditions.


2014 ◽  
Vol 66 (4) ◽  
pp. 520-524 ◽  
Author(s):  
Serkan Büyükdoğan ◽  
Süleyman Gündüz ◽  
Mustafa Türkmen

Purpose – The paper aims to provide new observations about static strain ageing in aluminium (Al) alloys which are widely used in structural applications. Design/methodology/approach – The present work aims to provide theoretical and practical information to industries or researchers who may be interested in the effect of static strain ageing on mechanical properties of Al alloys. The data are sorted into the following sections: introduction, materials and experimental procedure, results and discussion and conclusions. Findings – Tensile strength, proof strength (0.2 per cent) and percentage elongation measurement were used to investigate the effect of strain ageing on the mechanical properties. Wear tests were performed by sliding the pin specimens, which were prepared from as-received, solution heat-treated, deformed and undeformed specimens after ageing, on high-speed tool steel (64 HRC). It is concluded that the variations in ageing time improved the strength and wear resistance of the 6063 Al alloy; however, a plastically deformed solution-treated alloy has higher strength and wear resistance than undeformed specimens for different ageing times at 180°C. Practical implications – A very useful source of information for industries using or planning to produce Al alloys. Originality/value – This paper fulfils an identified resource need and offers practical help to the industries.


Author(s):  
S C Sharma

A well-consolidated composite of Al alloy 6061 reinforced with 4, 8 and 12 wt% garnet was prepared by a liquid metallurgy technique, the composite was heat treated for different ageing durations (T6 treatment), and its mechanical properties were determined by destructive testing. The results of the study indicated that, as the garnet particle content in the composites increased, there were marked increases in the ultimate tensile strength, compressive strength and hardness but there was a decrease in the ductility. There was an improvement in the tensile strength, compressive strength, and hardness with ageing due to precipitation. Precipitation in Al alloy 6061, with and without garnet particulate reinforcement, was studied using transmission electron microscopy. The fracture behaviour of the composites was altered significantly by the presence of garnet particles and the crack propagation through the matrix, and the reinforcing particle clusters resulted in final fracture.


2006 ◽  
Vol 128 (4) ◽  
pp. 891-894 ◽  
Author(s):  
M. Abdel Aziz ◽  
T. S. Mahmoud ◽  
Z. I. Zaki ◽  
A. M. Gaafer

In this article, the heat treatment and dry sliding wear behavior of Al-based AA6063 alloy reinforced with both TiC and Al2O3 ceramic particles were studied. The particles were synthesized by self-propagating high temperature synthesis (SHS) technique. The prepared composite alloy contains 5vol.%Al2O3 and 5vol.% TiC particles. The composite alloy was prepared by vortex method. To attain the peak hardness values of the alloys, age hardening behavior of the monolithic alloy and also the composite alloy was investigated. The wear tests were performed at room temperature using a pin-on-disk type apparatus. The results showed that the addition of TiC and Al2O3 particles increases the hardness of the AA6063 Al alloy and at the same time accelerates the aging kinetics. The sliding wear properties of AA6063 Al alloy were significantly improved by the addition of TiC and Al2O3 particles.


2017 ◽  
Vol 740 ◽  
pp. 9-16
Author(s):  
Ahmed Sahib Mahdi ◽  
Mohammad Sukri Mustapa ◽  
Mahmod Abd Hakim Mohamad ◽  
Abdul Latif M. Tobi ◽  
Muhammad Irfan Ab Kadir ◽  
...  

The micro-hardness and compression of recycling aluminum alloy AA6061 were investigated as a function of the different microstructure and constituent powder metallurgy method. Five specimens were selected to investigate the compression strength and microhardness. The first, as fabricated specimen (as compacted), the second was as heat treated by quenching and aging process. Three specimens were mixed with Graphite particles as a reinforcement material. Compression strength values were tested for the specimens as fabricated and heat treated which were 195 and 300 MPa, respectively. The improvement ratio was 52% for the specimen as heat treated. On the other hand, high wear resistance was given by the specimen as heat treated, whereas, the lower wear strength was at the specimen mixed with 4.5% Graphite. These results were attributed to that the wear resistance related to the microhardness value.


2020 ◽  
Vol 854 ◽  
pp. 30-36
Author(s):  
Yuri V. Gulkov ◽  
Anna V. Turysheva ◽  
Irina V. Vinogradova

The prospects of production of special properties steels in the Russian and global metal market are estimated. The necessity of using new types of steels is substantiated. The prospects of introducing steels with special properties developed by PJSC “Magnitogorsk Iron and Steel Company” to the market are determined. Evaluation of measures for the production of large volumes of products showed that there is a problem of a significant increase in the time of manufacturing and delivery of output products to the consumer. As measures to ensure the modernization of the technological complex of the steel enterprise and reduce the time for steel production, the system of jet heat treatment of metal is proposed. According to the results of comparative analysis of the MAGSTRONG H500 and HARDOX 500 alloys used in mining equipment under conditions of increased wear, it was revealed that the proposed method of heat treatment allows one to achieve high wear resistance properties, with high coefficients of tensile strength and toughness.


2013 ◽  
Vol 22 (4) ◽  
pp. 096369351302200 ◽  
Author(s):  
Necat Altinkök

In this study, initially Al2O3/SiC powder mix was prepared by reacting of aqueous solution of aluminium sulphate, ammonium sulphate and water containing SiC particles at 1200°C. 10 wt% of this hybrid ceramic powder with different sized SiC particles was added to a liquid Al matrix alloy during mechanical stirring between solidus and liqudus under inert conditions. Then hybrid Metal Matrix Composites (MMCs) was produced. The effect of reinforced particle size on tensile strength, bending strength, hardness resistance and wear resistance properties of hybrid reinforced MMCs were investigated. The mechanical test results revealed that bending, tensile strength and hardness resistance of the composites increased with decrease in ductility, with decrease size of the reinforcing SiC particulates in the aluminium alloy metal matrix. The wear behaviour of the hybrid ceramic reinforced aluminium matrix composites was investigated using pin-on-disc test at room temperature under dry conditions. Wear tests showed that the wear resistance of MMCs increased with increasing reinforced Al2O3/SiC particle size. Comparing the fine particle size MMCs with the coarse particle size MMCs were easily pulled out whole from the matrix. Microstructural examination showed that as well as coarse SiC particle reinforcement, a fine alumina particle reinforcement phase was observed within the aluminium matrix (A332).


Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1082
Author(s):  
Li-Shan Hsu ◽  
Pao-Chang Huang ◽  
Chih-Cheng Chou ◽  
Kung-Hsu Hou ◽  
Ming-Der Ger ◽  
...  

The electromagnetic rail catapult is a device that converts electrical energy into kinetic energy, which means that the strength of electrical energy directly affects the muzzle speed of armature. In addition, the electrical conductivity, electromagnetic rails and armature surface roughness, and the holding force of the rail are influencing factors that cannot be ignored. However, the electric ablation on the surface of the electromagnetic rails caused by high temperatures seriously affects the service life performance of the electromagnetic catapult system. In this study, electrochemically deposited nickel-phosphorus and nickel-molybdenum alloy coatings are plated on the surface of electromagnetic iron rails and their effects on the reduction of ablation are investigated. SEM (scanning electron microscopy) with EDS (energy dispersive spectroscopy) detector, XRD (X-ray diffraction), 3D optical profiler, and Vickers microhardness tester are used. Our results show that the sliding velocity of the armature decreases slightly with the increased roughness of the rail coating surface. On the other hand, the area of electric ablation on the rail surface is inversely related to the hardness of the rail material. The electrically ablated surface areas of the rails are in: annealed nickel–molybdenum < nickel–molybdenum < annealed nickel–phosphorus < nickel–phosphorus < iron material. Heat treatment at 400 and 500 °C, respectively for Ni–P and Ni–Mo alloys, significantly increases hardness due to the precipitation of intermetallic compounds such as Ni3P and Ni4Mo phases. Comprehensive data analysis shows that the annealed nickel–molybdenum coating has the best electrical ablation wear resistance. The possible reason for that might be attributed to the high hardness of the heat-treated nickel–molybdenum coating. In addition, the thermal resistance capability of molybdenum is better than that of phosphorus, which might also contribute to the high wear resistance to electric ablation.


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