Showing papers in "Journal of Minerals and Materials Characterization and Engineering in 2010"
TL;DR: In this article, the experimental results of the studies conducted regarding hardness, tensile strength and wear resistance properties of Al6061-SiC and Al7075-Al2O3 composites are presented.
Abstract: The aluminum based composites are increasingly being used in the transport, aerospace, marine, automobile and mineral processing industries, owing to their improved strength, stiffness and wear resistance properties. The widely used reinforcing materials for these composites are silicon carbide, aluminum oxide and graphite in the form of particles or whiskers. The ceramic particles reinforced aluminum composites are termed as new generation material and these can be tailored and engineered with specific required properties for specific application requirements. Particle reinforced composites have a better plastic forming capability than that of the whisker or fiber reinforced ones, and thus they have emerged as most sought after material with cost advantage and they are also known for excellent heat and wear resistance applications. In this paper it is aimed to present the experimental results of the studies conducted regarding hardness, tensile strength and wear resistance properties of Al6061-SiC and Al7075-Al2O3 composites. The composites are prepared using the liquid metallurgy technique, in which 2-6 wt. %’age of particulates were dispersed in the base matrix in steps of 2. The obtained cast composites of Al6061-SiC and Al7075-Al2O3 and the castings of the base alloys were carefully machined to prepare the test specimens for density, hardness, mechanical, tribological tests and as well as for microstructural studies as per ASTM standards. The SiC and Al2O3 resulted in improving the hardness and density of their respective composites. Further, the increased %’age of these reinforcements contributed in increased hardness and density of the composites. The microphotographs of the composites studied revealed the uniform distribution of the particles in the matrix system. The experimental density values were agreed with that of the theoretical density values of the composites obtained using the rule of mixture for composites. The dispersed SiC in Al6061 alloy and Al2O3 in Al7075 alloy contributed in enhancing the tensile strength of the composites. The wear factor K obtained using computerized pin on disc wear tester with counter surface as EN31 steel disc (HRC60) and the composite pin as specimens, demonstrated the superior wear resistance property of the composites.
215 citations
TL;DR: In this paper, a critical review of the current work of experiment, theory of micro-nanomechanics, and numerical analysis on characterizing mechanical properties of nanocomposites is presented.
Abstract: This paper presents a critical review of the current work of experiment, theory of micro-nanomechanics, and numerical analysis on characterizing mechanical properties of nanocomposites. First, the classifications of nanomaterials are presented. Then nanoindentation testing and the corresponding finite element modeling are discussed, followed by analytical modeling stiffness of nanocomposites. The analytical models discussed include Voigt and Reuss bounds, Hashin and Shtrikman bounds, Halpin–Tsai model, Cox model, and various Mori and Tanaka models. These micromechanics models predict stiffness of nanocomposites with both aligned and randomly oriented fibers. The emphasis is on numerical modeling includes molecular dynamics modeling and finite element modeling. Three different approaches are discussed in finite element modeling, i.e. multiscale representative volume element (RVE) modeling, unit cell modeling, and object-oriented modeling. Finally, the mechanism of nanocomposite mechanical property enhancement and the ways to improve stiffness and fracture toughness for nanocomposites are discussed.
160 citations
TL;DR: In this paper, a model of the response of a ship structure to this loading was determined experimentally by taking different weight percentage of glass fibers (E-300, mat form) with epoxy resin and comparison with fly ash reinforced composite.
Abstract: There has been significant increase in use of glass fibre reinforced composites as structural materials in naval mine countermeasure surface ships. Sea mines when detonated emit underwater shock waves, which could impart severe loading to naval ship structure; there are attempts to model the response of a ship structure to this loading. For the model to be accurate & useful material property data determined experimentally by taking different weight percentage of glass fibers (E-300, mat form) with epoxy resin & comparison with fly ash reinforced composite. Specimens in the form of cube of size 10X10X10 (mm’s) are used & results are presented. Fracture behaviour of composite can also be studied using SEM. SEM analysis is done to observe distribution of fly ash particles in matrix, resin fly ash interface, glass fibre matrix interface, glass fibre distribution etc,.
128 citations
TL;DR: A comparison of the mechanical properties and the microstructure of Al 6061 alloy with Al-TiB2 metal matrix composite containing 12% by weight TiB2p manufactured through the in-situ process was presented in this article.
Abstract: Al 6061 alloy is widely used for commercial applications in the transportation, construction and similar engineering industries. It possesses excellent mechanical properties in addition to good corrosion resistance due to which the alloy finds extensive application in naval vessels manufacturing. Al-TiB2 composite is a metal matrix composite (MMC) that can be manufactured using the in-situ salt-metal reaction. With TiB2 as the particulate addition the properties of Al 6061 alloy can be greatly improved. A comparison of the mechanical properties and the microstructure of Al 6061 alloy with Al–TiB2 metal matrix composite containing 12% by weight TiB2p manufactured through the in-situ process was presented.
125 citations
TL;DR: In this paper, a bio-ceramic powder was synthesized using waste eggshells as calcium source by a straight forward thermal method, which was carried out at high temperature.
Abstract: Hydroxyapatite bio-ceramic powder was synthesized using waste eggshells as calcium source by a straight forward thermal method. The process is carried out at high temperature. Different calcium phosphate phases were obtained just by changing the thermal treatment. HAp is the only apatite present in the reaction products, along with minute fractions of other calcium compounds. The final product was characterized by X-ray diffraction, Scanning electron microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FT-IR). Thermal analysis (TG–DTA) was carried out to investigate the thermal stability of HAp.
83 citations
TL;DR: In this article, the authors have explored a number of ways to improve and optimize the MRR including some unique experimental concepts that depart from the traditional EDM sparking phenomenon, which shares the same objectives of achieving more efficient material removal coupled with a reduction in tool wear and improved surface quality.
Abstract: Electrical discharge machining (EDM) is one of the earliest non-traditional machining processes. EDM process is based on thermoelectric energy between the workpiece and an electrode. Material removal rate (MRR) is an important performance measure in EDM process. Since long, EDM researchers have explored a number of ways to improve and optimize the MRR including some unique experimental concepts that depart from the traditional EDM sparking phenomenon. Despite a range of different approaches, all the research work in this area shares the same objectives of achieving more efficient material removal coupled with a reduction in tool wear and improved surface quality. The paper reports research on EDM relating to improvement in MRR along with some insight into mechanism of material removal. In the end of the paper scope for future research work has been outlined.
83 citations
TL;DR: In this article, X-ray diffractometry determination of composition and presence of crystalline material, scanning electron microscopy/EDAX examination of morphology of particles, as well as physical properties and refractoriness of bagasse ash has been studied.
Abstract: Utilization of industrial and agricultural waste products in the industry has been the focus of research for economical, environmental, and technical reasons. Sugar-cane bagasse is a fibrous waste-product of the sugar refining industry, along with ethanol vapor. This waste-product is already causing serious environmental pollution which calls for urgent ways of handling the waste. In this paper, Bagasse ash has been chemically and physically characterized, in order to evaluate the possibility of their use in the industry. X-ray diffractometry determination of composition and presence of crystalline material, scanning electron microscopy/EDAX examination of morphology of particles, as well as physical properties and refractoriness of bagasse ash has been studied.
77 citations
TL;DR: The emerging field of nanotechnology has created risk for environment and human health as there are no sufficient methods to test nanoparticles for health, safety and environmental impacts, especially in the size range lower than 50nm.
Abstract: The emerging field of nanotechnology has created risk for environment and human health. Nanoparticles are not a recent discovery. It has existed for many years. Today synthesis of nanoparticles takes place for many applications in various field of science, technology, medicine, colloid technologies, diagnostics, drug delivery, health impacts, food, personal care applications etc. In spite of this, toxicology of nanoparticles is poorly understood as there are no sufficient methods to test nanoparticles for health, safety and environmental impacts, especially in the size range lower than 50nm.
74 citations
TL;DR: In this article, the effect of chemical treatment on the constituents and tensile properties of sisal fiber (Agave Sisalana) was investigated and the results showed that the chemical treatments enhance the removal of lignin and hemicelluloses which are detrimental to the bonding strength of composite produced from natural fibres except that of sample treated with alkaline peroxide.
Abstract: This work was carried out to investigate the effect of chemical treatment on the constituents and tensile properties of sisal fibre (Agave Sisalana). Sisal leaves were cut and buried underground close to the stream and were wetted with water regularly in order to ensure proper fermentation for about 15 days. The fermented leaves were washed and sun dried. The dried sisal fibre obtained was treated mechanically with chemicals after which the percentages of their constituents were characterized and, their tensile properties determined with Instron universal tensile testing machine. The results show that the chemical treatments enhance the removal of lignin and hemicelluloses which are detrimental to the bonding strength of composite produced from natural fibres except that of sample treated with alkaline peroxide. The results of the tensile test revealed that sample treated sequentially with KOH, acetic acid, NaCl and HCl has the best tensile properties followed by the sample treated with alkaline peroxide.
66 citations
TL;DR: In this paper, the effect of fly ash as filler in mechanical properties of HDPE is described, and three different particle size of fly-ash was used. And the microstructure was investigated through scanning electron microscopy (SEM).
Abstract: Effect of fly ash as filler in mechanical properties of HDPE is described in this study. Three different particle size of fly ash was used. Concentration of fly ash was varied up to 40 % by weight. The composites were prepared using twin screw extruder and then test specimens were prepared by injection molding. Tensile, flexural and impact properties were tested. The microstructure was investigated through scanning electron microscopy (SEM) of the fractured samples. Both tensile and flexural strengths and moduli were found to increase with fly ash addition. Tensile elongation drastically reduced at fly ash concentration greater than 10%. With increasing fly ash concentration impact resistance decreased up to about 15% fly ash concentration and then did not reduce significantly on further addition. Composites with smallest size fly ash particles proved to be better in enhancing strength and relative elongation. Modulus and impact resistance did not seem to depend much on particle size.
59 citations
TL;DR: In this article, an experimental investigation was conducted to study the effect of hybrid composite specimen subjected to in-plane tensile and compressive loading, and it was revealed that the specimens with higher percentage of steel sustain greater loads and also the strengths are superior in case of 0/900 oriented specimens.
Abstract: An experimental investigation was conducted to study the effect of hybrid composite specimen subjected to in-plane tensile and compressive loading. The laminated specimens in accordance with ASTM standards were fabricated using steel and nylon bi-directional mesh as reinforcements and polyester as the binder. The various volume fractions and fiber orientations were used in which the percentage of polyester (40%) was maintained constant. From the investigations it is revealed that, the specimens with higher percentage of steel sustain greater loads & also the strengths are superior in case of 0/900 oriented specimens. A relationship between the tensile/compressive strength, fiber content and orientation has been established.
TL;DR: In this article, the influence of friction and wear parameters on the friction and sliding wear rate of glass fiber reinforced vinylester composites filled with fly ash particulates was investigated using a pin-on-disc wear apparatus under dry sliding conditions.
Abstract: The tribological behavior of glass fiber reinforced vinylester composites filled with fly ash particulates were studied using a pin-on-disc wear apparatus under dry sliding conditions. The influence of friction and wear parameters like (pv) factor, sliding distance and percentage of filler content, on the friction and sliding wear rate were investigated. A plan of experiments, based on the Taguchi technique, was performed to acquire data in a controlled way. An orthogonal array and analysis of variance (ANOVA) were applied to investigate the influence of process parameters on the coefficient of friction and sliding wear behaviour of these composites. The Taguchi design of experiment approach eliminates the need for repeated experiments and thus saves time, material and cost. Taguchi approach identifies not only the significant control factors but also their interactions influencing the coefficient of friction and specific wear rate predominantly. The results showed that the inclusion of fly ash as filler materials in glass vinylester composites decreases the coefficient of friction and increases the wear resistance of the glass vinylester composites significantly.
TL;DR: In this article, nonlinear wave resonance concepts have been proposed to contain explanations for the dramatic increase in dispersion performance, and more specifically, the effect of intermittency chaos, which is made because of the similarity between the pressure wave pattern in the double sonication system and sliding charge density wave with an A.C. electric field, which was cited to exhibit intermittency behavior.
Abstract: A double ultrasonic source has been shown to dramatically increase dispersion efficiency of carbon nanotubes. Thermal measurements of dispersing fluid only show temperature rises commensurate with the power levels of the two ultrasonic sources; which is validated by predictions of statistical energy analysis (SEA) based on wave superposition principles. In this paper, nonlinear wave resonance concepts have been proposed to contain explanations for the dramatic increase in dispersion performance, and more specifically, the effect of intermittency chaos. Such a hypothesis was made because of the similarity between the pressure wave pattern in the double sonication system and sliding charge density wave with an A.C. electric field, which was cited to exhibit intermittency behavior.
TL;DR: In this article, a new combination of vortex method and pressure die casting technique was used for aluminum alloy-silicon carbide composite work piece using a copper electrode in an Electrical Discharge Machine.
Abstract: Aluminum based metal matrix composites (MMCs) offer potential for advanced structural applications when high specific strength and modulus, as well as good elevated temperature resistance, are important. In the present work, aluminum alloy-silicon carbide composites were developed using a new combination of vortex method and pressure die casting technique. Electrical Discharge Machining (EDM) studies were conducted on the aluminum alloy-silicon carbide composite work piece using a copper electrode in an Electrical Discharge Machine. The Material Removal Rate (MRR) and surface roughness of the work piece increases with an increase in the current. The MRR decreases with increase in the percent weight of silicon carbide. The surface finish of the machined work piece improves with percent weight of silicon carbide.
TL;DR: In this article, the role of silver- Titania nanoparticles synthesized and deposited on different types of fabrics using ultrasound irradiation under an atmosphere of argon gas and decreasing both the cavitational threshold and intensity of ultrasound power has been reviewed.
Abstract: Surface modification is an important element of textile manufacturing. The final properties of a textile material are critical in determining how they perform for their given end use. More recently, botany and nanotechnology have united to explore not only the beauty and cleanliness of the leaf, but also its lack of contamination and bacteria, despite its dwelling in dirty ponds. On the basis of lotus leaf concept scientist developed a new concept “Self cleaning textile” the textile surface which can be cleaned itself without using any laundering action. In this paper, the role of silver- Titania nanoparticles synthesized and deposited on different types of fabrics using ultrasound irradiation under an atmosphere of argon gas and decreasing both the cavitational threshold and intensity of ultrasound power has been reviewed. The excellent antibacterial activity of the Ag–Titania fabric composite against Escherichia coli (gram-negative) and Staphylococcus aureus (gram-positive) cultures also reviewed with reference to Indian scenario.
TL;DR: In this article, the effects of heat treatment on the mechanical properties of rolled medium carbon steel were investigated and the result showed that the steel developed has excellent combination of tensile strength, impact strength and ductility which is very attractive for structural use.
Abstract: Investigations were carried out to study the effects of heat treatment on the mechanical
properties of rolled medium carbon steel. The steel was heated to the austenizing temperature of
830℃ and water quenched; It was reheated to the ferrite – austenite two phase region at a
temperature of 745℃ below the effective Ac3 point. The steel was then rapidly quenched in water and tempered at 480℃ to provide an alloy containing strong, tough, lath martensite (fibres) in a ductile soft ferrite matrix. The result shows that the steel developed has excellent combination of tensile strength, impact strength and ductility which is very attractive for
structural use.
TL;DR: In this paper, the effect of fly ash and mica on the percentage crystallinity of PEEK composites was studied by using modulated differential scanning calorimeter (MDSC).
Abstract: Polyetheretherketone (PEEK) composites were developed using fly ash and mica as fillers. PEEK composites of 5-30 wt% loading were compounded using twin screw extruder. Tensile strength, tensile modulus and flexural modulus increased with the incorporation of both the fillers in PEEK matrix. Tensile modulus of PEEK fly ash composites was found to be higher than PEEK mica composites. Charpy impact strength of PEEK mica composites improved drastically up to 15 wt% of filler but in PEEK fly ash composites charpy impact strength was decreased. The effect of fly ash and mica on the percentage crystallinity of PEEK composites was studied by using modulated differential scanning calorimeter (MDSC). Limiting oxygen index (LOI) of PEEK fly ash and mica composites also improved by 11% and 24% respectively than pure PEEK at 30 wt% loading respectively. The dynamic modulus of PEEK composites shows over 133% increment at 100-250 °C, indicating improvement of elevated temperature mechanical properties. Effects of filler on the morphology of PEEK composites have also been discussed.
TL;DR: In this article, the behavior displayed by a thermoluminescence (TL) glow peak as radiation dose increases in the Limestone of Patharia mines of Chhattisgarh in India is reported.
Abstract: Behavior displayed by a thermoluminescence (TL) glow peak as radiation dose increases in
limestone of Patharia mines of Chhattisgarh in India { Location : Durg (dist.) Elevation 274
meters, E 81o 22’ 48” N – 21o 23’ 40.5’’ way point 196} have been reported. The glow curve of Limestone peak is observed at 306.1℃ & slightly shifting of peak is observed at low temperature side. The value of activation energy and order of kinetics for 306.1℃ peak suggest low fading & high stability.
TL;DR: In this article, high energy ball mill was used to disperse multi-walled carbon nanotubes in AA 4032 alloy and the phase evolution and changes in crystallite size and lattice strain were analyzed using X-ray diffractometer (XRD).
Abstract: Powder metallurgy has emerged as a promising technique to develop carbon nanotubes reinforced metal matrix composites. In this work, high energy ball mill was used to disperse multi-walled carbon nanotubes in AA 4032 alloy. The nanocrystalline nature of AA 4032 was obtained by milling the elemental powders for 30 hours. Different mass fractions of carbon nanotubes were added in the matrix at end of 29th hour. The phase evolution and changes in crystallite size and lattice strain were analyzed using X- ray diffractometer (XRD). SEM analysis reveals the morphological changes during the milling process. Transmission electron microscopy (TEM) studies reveal the presence of CNTs in the matrix and evidenced the uniform distribution of CNTs inside the matrix.
TL;DR: In this paper, the study of the sensitization and desensitization of 316L stainless steel at the normalizing temperatures of 750- 950 0 C and soaking times of 0.5, 1, 2 and 8 hrs was conducted.
Abstract: Austenitic stainless steels with excellent corrosion resistance and good weldability have wide applications in industry. These iron-based alloys contain a high level of chromium which form protective oxide film on the surface hence resisting corrosion. The oxide film regenerates when damaged, making the steel 'stainless'. However, carbide precipitation due to a welding process or heat treatment can cause the occurrence of chromium-depleted zones at the boundaries, leading to a phenomenon known as sensitisation, in which the depleted zones become the focus of the intense corrosion. The present work was concerned with the study of the sensitization and desensitisation of 316L steel at the normalizing temperatures of 750- 950 0 C and soaking times of 0.5, 1, 2 and 8 hrs. 316L stainless steel was observed to be sensitized when heated to 750- 850 0 C and held for short soaking times of 0.5 – 2hrs before normalizing. Increasing soaking times at these temperatures to 8 hrs triggered the desensitization process which was fully accomplished at 750 0 C but ongoing at 800 and 850 0 C. At 900 0 C, sensitization did not occur at 30 mins soaking time but observed at soaking times of 1 and 2hrs. At a longer soaking time of 8 hrs, there was full desensitization. At 950 0 C, sensitization was already observed at 30 mins. Soaking time and desensitization was observed to be in progress at 1 and 2 hrs soaking time. By 8 hrs there was full desensitization. Thus it was observed that at 950 0 C, diffusion of Cr was thermally aided making desensitization fast. The hardness of normalized 316L stainless steel was also observed to decrease with soaking time and normalization temperature.
TL;DR: In this article, an experimental investigation concerning the low-velocity impact response of woven glass fiber epoxy matrix composite laminates was performed according to ASTM standards using an instrumented falling weight impact testing machine.
Abstract: This work presents the results of an experimental investigation concerning the low-velocity impact response of woven glass fiber epoxy matrix composite laminates. Experimental tests were performed according to ASTM standards using an instrumented falling weight impact testing machine. Impact tests were conducted to characterize the type and extent of the damages observed in laminate subjected to different impact velocities: 2 to 4.5 m/sec. The response of these laminates to drop-weight low velocity impact at energy levels ranging from 3 to 15 J was investigated. At impact velocity of 4.429 m/sec, there is clearly a catastrophic failure of laminates. It was found that the laminates exhibited two types of failure modes viz., crack initiation and perforation of the laminate.
TL;DR: Mucuna Seed Coagulant is an effective coagULant obeying the theory of fast coagulation at the conditions of the experiment, and the minimum value of coag-flocculation efficiency E (%) recorded is greater than 88.00 %.
Abstract: The coag-flocculation performance of Mucuna Seed Coagulant as affected by pH variation in
coal washery effluent has been investigated at room temperature using various dosages of
unblended Mucuna Seed Coagulant. In addition, coag-flocculation parameters such as Coagflocculation reaction order α, αth order coag-flocculation constant K, Collision factor for Brownian Transport βBr, Smoluchowski constant KR,, Collision Efficiency ep, and Coagulation Period τ1/2 were determined. Turbidity measurement was employed using the nephelometric (turbidimetric) standard method while Mucuna Seed Coagulant preparation was adopted from the works of Adebowale and Adebowale (2007). The maximum Mucuna Seed Coagulant parameter performance is recorded at α of 2, K of 8.3334 x 10-3 m3/kg.s, dosages of (0.15 kg/m3; 0.2 kg/m3 ; 0.25 kg/m3); pH of 6 and τ1/2 of 1.7339 sec while the minimum parametric performance is recorded at α of 1; K of 6.3001 x 10-4 s-1; dosage of 0.2kg/m3; pH of 8 and τ1/2 of 1100.2161seconds. The minimum value of coag-flocculation efficiency E (%) recorded is greater than 88.00 %. Conclusively; Mucuna Seed Coagulant is an effective coagulant obeying the theory of fast coagulation at the conditions of the experiment.
TL;DR: In this article, the thermal ageing behavior model of Al-Cu-Mg/Bagasse ash particulate composites with 2-10wt% bagasse ash particles produced by double stir-casting method was developed in terms of weight fraction of Bagasse ash, ageing temperature and time.
Abstract: The thermal ageing behaviour model of Al-Cu-Mg/Bagasse ash particulate composites with 2- 10wt% bagasse ash particles produced by double stir-casting method was developed in terms of weight fraction of bagasse ash, ageing temperature and time. Hardness values measurement was used in determining the ageing behaviour, after solution and age-hardened heat-treatment. The experimental results demonstrate that the bagasse ash was the major parameter in the ageing behaviour, followed by ageing temperature. The hardness values decreased as the ageing time increases, interaction of weight of bagasse ash, ageing time and ageing temperature. Moreover, the optimal combination of the testing parameters could be predicted. The predicted hardness values were found to lie close to that of the experimentally observed ones. The developed mathematical model can be employed for optimization of the process parameters of the ageing behaviour of Al-Cu-Mg/Bagasse ash particulate composites with respect to hardness values.
TL;DR: In this paper, the effect of montmorillonite (MMT) on the morphology and mechanical properties of polypropylene (PP) PP/MMT nanocomposites have been prepared by melt mixing using maleic anhydride grafted polypropylon (MAH-g-PP) as compatibilizing agents Melt mixing was achieved using twin screw extruder.
Abstract: This article addresses the effect of montmorillonite (MMT) on the morphology, and mechanical properties of polypropylene (PP) PP/MMT nanocomposites have been prepared by melt mixing using maleic anhydride grafted polypropylene (MAH-g-PP) as compatibilizing agents Melt mixing was achieved using twin screw extruder The MAH-g-PP used as compatibilizer helped the dispersion of the MMT in PP matrix The influence of MMT on the impact fracture morphology of the nanocomposites was studied by scanning electron microscopy (SEM) The polymer composites were characterized by using different techniques such as X-ray diffraction (XRD), tranmission electron microscopy (TEM) and mechanical characterization as per ASTM standards The mechanical properties of strength and modulus of the nanocomposites increases with addition of 5 wt% of nanoclay and impact strength and hardness of the nanocomposites increses with addition of 3 wt% of nanoclay
TL;DR: In this paper, the effect of silicon carbide (SiC) particulate fillers incorporation on two-body abrasive wear behavior of Glass Fabric - Epoxy (GE) composites was investigated and findings are analyzed.
Abstract: The effect of silicon carbide (SiC) particulate fillers incorporation on two-body abrasive wear behaviour of Glass Fabric - Epoxy (GE) composites was investigated and findings are analysed. The mechanical properties such as impact strength and surface hardness of the composites have also been reported. The wear behaviour of the composites were performed using pin-on-disc tester at varying abrasive distances viz., 25, 50, 75 and 100 m at a constant load of 10 N. The experiment was conducted using two different water proof silicon carbide (SiC) abrasive papers of 600 and 1000 grit size at a constant speed of 200 rpm under multi-pass condition. The wear loss of the composites was found increasing with the increase in abrading distances. A significant reduction in wear loss and specific wear rates were noticed after incorporation of SiC filler into GE composite. This result indicates that the significant influence of SiC filler allowing less wear of matrix during abrasion which in turn facilitates lower fiber damage, due to the presence of SiC particles on the counter surface, which act as a transfer layer and effective barriers to prevent large-scale fragmentation. The worn surface features, were examined through scanning electron microscopy (SEM), in order to probe the wear mechanism.
TL;DR: In this article, the effects of Al-6%Si alloy particles on the ascast microstructure and properties of Tin Tailings ceramics matrix composites produced by powder metallurgy method have been studied.
Abstract: Ceramic matrix composites reinforced with metals have been developed to overcome the intensive brittleness and lack of reliability of monolithic ceramics, with a view to introduce ceramics in structural parts used in severe environments such as rocket and jet engines, gas turbines for power plants, heat shields for space vehicles, fusion reactor first wall, aircraft brakes, heat treatment furnaces. In view of these the effects of Al-6%Si alloy particles on the ascast microstructure and properties of Tin Tailings ceramics matrix composites produced by powder metallurgy method have been studied. 5-30 weight percent Al-6%Si alloy particles were added. The results revealed that, addition of Al-6%Si alloy reinforcement increased the linear shrinkage, strength and impact energy with a decreased in density, porosity and hardness value. These increases in strength and impact energy are attributed to the uniform distribution and strong bonding of the soft metal phase in the hard ceramic matrix. These results show that better properties are achievable by addition of Al-6%Si alloy to Tin Tailings.
TL;DR: In this paper, the annealing heat treatment effects on steel welds were investigated and the properties of the weld investigated were hardness value and toughness, and micro-structural analysis of the steel rods were carried out.
Abstract: This paper reports investigations made on the annealing heat treatment effects on steel welds. The properties of the weld investigated were hardness value and toughness. Micro examination of the samples was also done with optical microscopy. Four (4) different grades of steel rods (10mm) in diameter were obtained. The range of the carbon contents of the steel rods was from 0.16 wt pct C to 0.33 wt pct C. From each grade of the steel materials, grooved specimen of about 150mm were prepared. The groves were then filled to create welds using arc welding. The resulting welds were then subjected to annealing heat treatment. The hardness values and toughness of the welds were determined. The microstructural analyses of the welds were carried out as well. The results show that hardness and toughness were dependent on the carbon content. There was also significant microstructural modification due to heat treatment.
TL;DR: In this paper, a mathematical model for sound weld deposit area of a mild steel specimen was developed to optimize various Gas Metal Arc welding parameters including welding voltage, welding current, welding speed and nozzle to plate distance (NPD).
Abstract: Gas Metal Arc Welding is a process in which the source of heat is an arc format between consumable metal electrode and the work piece with an externally supplied gaseous shield of gas either inert such as argon, helium. This experimental study aims at optimizing various Gas Metal Arc welding parameters including welding voltage, welding current, welding speed and nozzle to plate distance (NPD) by developing a mathematical model for sound weld deposit area of a mild steel specimen. Factorial design approach has been applied for finding the relationship between the various process parameters and weld deposit area. The study revealed that the welding voltage and NPD varies directly with weld deposit area and inverse relationship is found between welding current and speed with weld deposit area.
TL;DR: In this paper, the applicability of selective flocculation to Indian iron ores using corn starch as flocculant was studied and a detailed mineralogical and chemical characterization of iron ore and kaolinite were performed.
Abstract: High demand of steel necessitates the use of low and lean grade iron ores by beneficiating them. However the fines, slimes and tailings generated in the process of beneficiating these low grade iron ores contains good amount of iron values. These iron values can be recovered by further beneficiating the fines, slimes and tailing by selective flocculation, which is defined as the selective agglomeration of iron ore particles using flocculant. In the present study an attempt has been taken to study the applicability of selective flocculation to Indian iron ore using corn starch as flocculant. A detail mineralogical and chemical characterization of iron ore and kaolinite were performed; in addition to this the flocculant was characterized by FTIR which gives an idea about the functional groups present in the flocculant. Different experiments were performed to optimize the operating parameters of the selective flocculation process. It was observed that product grade and recovery was strongly affected by pH of slurry and solid concentration compared to the flocculant dose. It was also found that the iron value can be upgraded to 63-66.9 % from the feed iron value of 37.65-55.33 % with the recovery of 63-90 %.
TL;DR: In this paper, the effect of the mica with different particle size and different filler concentration (10 to 50 weight percent) on the mechanical and electrical properties of the polyvinyl chloride (PVC) was investigated.
Abstract: The performance of the composites is determined on the basis of the interface bonding of the filler and the polymer matrix. Particulate filled polymer composites are used extensively for their wide range of applications at low cost. In this study, the effect of the mica with different particle size and different filler concentration (10 to 50 weight percent) on the mechanical and electrical properties of the polyvinyl chloride (PVC) was investigated. The PVC composites of water ground mica were prepared by Haake Rheocord 9000 machine, with Rheomix 600 using rotor type roller blades. Mechanical properties such as stiffness, and Young’s modulus of the PVC mica composites were found increasing with increase in mica loading, whereas elongation at break and tensile strength was found to be decreasing with the mica loading. Dielectric strength and surface resistance were found increasing with increasing mica loading whereas there was no significant increase of arc resistance of the composites. Morphological studies revealed that there is good dispersion and wetting of the mica with PVC matrix. SEM micrographs of the composites were studied for finding the filler dispersion and fracture analysis of the test samples.