Fly Ash Composites Research Articles

Study on conventional and microwave assisted sintering of Cu-FA composites

Abstract In this study we have diligently made efforts to reinforce Copper (Cu) with Fly Ash (FA) via Powder metallurgical path to form Cu- FA composite. We have critically investigated the effects of sintering mode on Cu-FA composite properties and variation of mechanical properties with change in weight percentage of FA in the composite. The sintering effect of Cu-FA pellets of 3, 6 and 9 wt% of FA in a microwave furnace of 2.5 GHz was compared with that processed in a conventional furnace. The elemental analysis and morphology of the prepared samples were characterized using Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) and optical images. Results indicated a rise in hardness values with the increase of fly ash in composite up to 6 wt% and then a drop down in value to that of pure Cu due to exposure of Cu matrix during sintering. Wear rate decreases with increase of fly ash in composite. Our results imperatively showed microwave sintered samples were observed to be superior in mechanical properties like hardness, wear resistance as well as densification response compared to their conventional counterparts.

Investigations on microstructural and microhardness developments in sintered iron–coal fly ash composites

The present work is aimed to explore the microstructural and mechanical characteristics of coal-fly ash reinforced iron metal-matrix composites (IMMCs), synthesized through powder metallurgy technique. Coal-fly ash wt%, compacting load and sintering temperature were considered as the input variables, whereas sintered density and microhardness of the composites were taken as the output responses. Flowability and compressibility of the starting materials were demonstrated using Hausner ratio and Carr’s index. Decorous morphological, crystallographic and elemental characteristics of the starting materials and IMMCs were deliberated using Scanning electron microscopy, X-ray diffraction and Energy-dispersive X-ray spectroscopy investigations respectively. A significant improvement in the microhardness of IMMCs by 50% and drop in density by 35% were found at 15 wt% as compared to 0 wt% reinforcement. The substantial increase in the microhardness eventually resulted in an increase in their specific microhardness by a factor of two. Significant improvements in the microhardness of IMMCs at 15 wt % of reinforcement, compacted at 10 ton and sintered at 1150°C were found to be prompted by the strengthening mechanisms like load transfer, Hall–Petch effect and Taylor strengthening. The analytically calculated microhardness in the light of strengthening mechanisms was found smaller than the corresponding experimental values as a function of wt % of reinforcement. Further, statistical analysis of the obtained results was carried out using response surface methodology.

Investigation of process parameters by abrasive assisted electrochemical micro drilling process on Al - 6061with SiC and Fly ash composites

This attempt investigates on upgrading the required parameters of micro hole machining process like frequency, voltage, electrolyte concentration of abrasive assisted Electrochemical machining process. This work focuses on optimizing the methodology of abrasive assisted ECM process parameters and comparing it with straight ECM process. The experimentation is done on AL6061 with hybrid reinforced SiC and Fly ash particles at constant percentage weight. Upgrading process parameter is a statistical technique, where the independent input process parameters such as frequency, voltage, electrolyte concentration were imported to initiate the AECM process. The process performance is measured in terms of material removal rate (MRR) and precision of micro hole dimension (OC) and the results obtained were compared for both process(abrasive and without abrasive ECM for AL6061-10 wt% of SiC -10 wt% of Fly ash). The hybrid composites of Al6061 containing 10 wt% of (SiC& Fly ash) particles were prepared by using liquid metallurgy route. The microstructure, wear and mechanical properties of the fabricated AMCs were analyzed.

Comparative study of fly ash/sugarcane fiber reinforced polymer composites properties

This paper discusses mechanical, morphological, infrared spectral, and thermal properties of fly ash/sugarcane fiber reinforced epoxy polymer composites. Samples were prepared with and without the addition of 2 wt% of fly ash. Sugarcane fiber additions were varied from 0 wt% to 10 wt% (with an increment of 2 wt% for each sample), while the epoxy was used as a binder. A comparative study of these properties was completed on samples with and without the addition of fly ash in the composites. Based on the results obtained, the addition of 2 wt% of fly ash improved the tensile strength and hardness properties but reduced the flexural strength of the composites. Additions of fly ash reduced bubble or void formation in the composites, while toughening the composites and improving adhesion between the fiber and matrix. Samples with 4 w% of fiber and 2 wt% of fly ash composites showed high tensile strength and hardness properties, while 2 wt% of fiber composites showed high flexural strength.

Multi-response optimization of AA 8011 and 12 wt.-% fly ash composites

Abstract The present research work is focused on the production of aluminum alloy 8011 with 12 wt.-% fly ash composite by using the stir casting method. A three-level central composite design experiment is developed using response surface methodology (RSM) with various parameters. Load, time and sliding velocity are varied in the range of (5-15 N), (5-15 min) and (1.5-4.5 m × s-1), respectively. Dry sliding wear tests are performed as per the experimental design using a pin-on-disc at room temperature. This paper describes how optimization studies were carried out on a dry sliding wear process with multi-response characteristics based on MCDM using the TOPSIS approach. The process parameters, load, time and sliding velocity are optimized with multi-response characteristics, including the wear rate (WR), and the coefficient of friction (COF). A sensitivity analysis is also carried out and compared with the relative impact of input parameters on wear behavior in order to verify the measurement errors on the values of the uncertainty in estimated parameters. The experimental results indicate that the multi-response characteristics of aluminum alloy 8011 with 12 wt.-% fly ash composite used during the wear behavior process can be enhanced through the TOPSIS method.

Impact Resistance and Fracture Surface of Al6061 Hybrid Composites Reinforced by Fly Ash and Calcium Oxide

Phase formation, impact resistance, and fracture surface were investigated in unreinforced Al6061, Al6061-5wt% fly ash and Al6061 hybrid composites containing 5wt% fly ash and 1,3 wt% CaO. The Al6061 composites were fabricated the stir casting process. The XRD patterns reveal the formation of second phases (MgAl2O4, CaAl4O7 and MgSiO3), which were found in the Al6061 hybrid composites. The average grain size of Al6061 hybrid composite are much smaller than that of unreinforced Al6061.The impact resistance was enhanced by approximately 67% in Al6061 hybrid composite as compared to unreinforced Al6061 alloy. Brittle fracture indicting brittle fracture was observed in unreinforced Al6061 alloy while evidence of a mixture of brittle and ductile fracture was found in the Al6061 hybrid composites.

Preference selection of brake friction composite using entropy-VIKOR technique

Raw and milled fly ash, varying from 20 wt% to 35 wt%, were utilized exclusively for the fabrication of brake friction composites. The fabricated friction composites were tested for the friction and wear response under two sliding conditions i.e. 200 N, 3.3 m/s and 200 N, 5 m/s using wear and friction monitoring test setup. The optimal friction composite from the developed raw fly ash composite (RFC) and milled fly ash composite (MFC) specimens was obtained using Entropy-VIšekriterijumsko KOmpromisno Rangiranje (VIKOR) technique based on their performance evaluation criteria (PEC) such as coefficient of friction, stability coefficient, variability coefficient, friction fluctuation, specific wear rate and the interface disc-pin temperature. The weight of each PEC was determined by Entropy method which were used in the VIKOR technique to calculate the ranking of the friction composites at both the sliding conditions. The ranking results showed that the MFC-30 specimen satisfied all the PEC and ranked 1 at both the rigorous sliding conditions. Based on the optimization results, the composition of MFC-30 may be recommended for the development of brake pads.

A Brief Review of Fly Ash as Reinforcement for Composites with Improved Mechanical and Tribological Properties

Fly ash (FA) is one of the particulate wastes generated during combustion of coal in thermal power plants. Around 110 million tons of FA is generated in the USA every year, and 60% of it is deposited in landfills. Utilization of FA can create value for this waste material and also help the environment. FA is essentially a mixture of metal oxides that can be used as a filler reinforcement in metal and polymer composites. FA as a filler material reduces the amount of metals and polymer, reducing embodied energy. Hollow FA particles, called cenospheres, can provide the advantage of low density in composites as well as higher hardness and strength. FA also reduces the coefficient of thermal expansion. This article provides a brief review to capture the state of the art on the mechanical and tribological behavior of composites reinforced with FA to identify the possible benefits of using this waste material. The corrosion performance of metal matrix FA composites is also explored. Future perspectives in this field are discussed based on the potential applications of FA-filled composites.

Study on thermal, mechanical and morphological properties of recycled poly(vinyl chloride)/fly ash composites

AbstractThe present study deals with the development of composite materials utilizing recycled poly(vinyl chloride) (r‐PVC) recovered from waste electrical and electronic materials and waste fly ash obtained from thermal power plants. The effect of the incorporation of fly ash on the mechanical, thermal and morphological properties of the r‐PVC matrix was studied. The primary characterization of r‐PVC and fly ash was done employing FTIR, EDX, particle size analysis and XRD analysis. Subsequently, fly ash with a particle size of approximately 9.29 μm was incorporated within the r‐PVC matrix. Composite sheets were prepared using a melt blending process followed by compression moulding. The mechanical test revealed an increase in the tensile strength and elongation at break of the r‐PVC/fly ash composite up to 30 wt% loading of fly ash beyond which there was a decrease in the tensile strength. The impact strength, however, decreased with increasing fly ash content in the r‐PVC matrix. The morphological properties of the composites showed a good distribution of the filler within the recycled matrix. The thermal properties of r‐PVC also improved with the incorporation of fly ash which was revealed from DSC and TGA studies. The water absorption test showed an increase in water uptake with the addition of fly ash in the r‐PVC matrix. © 2020 Society of Chemical Industry

Effect of Reinforcement on Compacting Characteristics of Aluminum/10-Al2O3/Fly Ash Metal Matrix Composite

Abstract Aluminum metal matrix composites are attractive and effective materials because of their unique properties. These properties include high specific strength, light weight, high specific stiffness, excellent wear resistance, good corrosion resistance, and greater elastic modulus compared with the base alloy. They are used in aerospace, automotive, marine, mining, and mechanical structures. Fly ash, an inexpensive waste by-product obtained after the combustion of coal in thermal power plants, is considered as a reinforcement particle in the present study. The aim is to investigate the effect of fly ash in Al-10 weight percentage (wt%) aluminum oxide (Al2O3) metal matrix composites using statistical optimization techniques. One factor and Taguchi approaches are used in planning and designing the experiments. Al/10 wt% Al2O3 with 0, 5, 10, and 15 wt% fly ash composites are prepared with the powder metallurgy technique at 300, 400, and 500 MPa compaction pressure with 90, 120, and 150-μm fly ash particle sizes. The wt% of fly ash, compaction pressure, and particle size are the process parameters. Performance parameters such as ejection force and green density, hardness, and compressive strength are considered. The ejection force and green density decreased with the increase in the weight percent of fly ash. Hardness increased with the increase in fly ash content. Compressive strength increased with the increase in fly ash up to 5 wt% and subsequently decreased.

Potentiodynamic Corrosion Characterization of Hybrid Aluminium Composites for Advanced Engineering Applications

Corrosion characterization of Aluminium composites is a significant study planned for assessing the capability of utilizing the materials for aviation and automobile parts. Aluminium 5083 is a particular class of alloys which is known for its corrosion resistance in extraordinary conditions and is utilized in aerospace components. However, the experimentations on impact of reinforcements, for example, the effect of Silicon carbide and Flyash on corrosion properties of Aluminium 5083 alloys is still in its incipient stage and not much literature is available outlining the corrosion attributes. The present work includes the fabrication of Aluminium 5083 – Silicon carbide – Flyash composites and investigation of the corrosion conduct of these composites. The composites are fabricated by stir casting procedure, considering silicon carbide particulates varied in the scope of 3 wt.% to 9 wt.% at an intermittent intervals of 2 wt.%. The composition of fly ash in the present work is limited to 5 wt. % for restricting the porosity after conducting preliminary trials. The composite materials considered in this research are assessed for corrosion by Potentio-dynamic test, which is accomplished utilizing a test arrangement comprising of five mouth jar with calomel electrode and a working cathode (comprising of the specimen held rigidly with a copper wire and secured with Teflon tape notwithstanding a region of one square centimeter exposed to the electrolyte). The anodic and cathodic potentio-dynamic polarization estimations are acquired as tafel plots in the PC that is interfaced with the test arrangement. The outcomes reveal that the corrosion current (Icorr) increases with the increase in the weight percentage of Silicon carbide in the metal matrix. The electrolyte considered for the potentio-dynamic test is and 1 M HCl (acidic) medium.

Evaluation of alumina reinforced oil fly ash composites prepared by spark plasma sintering

AbstractThe thermomechanical behavior of micro/nano‐alumina (Al2O3) ceramics reinforced with 1‐5 wt.% of acid‐treated oil fly ash (OFA) was investigated. Composites were sintered using spark plasma sintering (SPS) technique at a temperature of 1400°C by applying a constant uniaxial pressure of 50 MPa. It was evaluated that the fracture toughness of micro‐ and nanosized composites improved in contrast with the monolithic alumina. Highest fracture toughness value of 4.85 MPam1/2 was measured for the nanosized composite reinforced with 5 wt.% OFA. The thermal conductivity of the composites (nano‐/microsized) decreased with the increase in temperature. However, the addition of OFA (1‐5 wt.%) in nanosized alumina enhanced the thermal conductivity at an evaluated temperature. Furthermore, a minimum thermal expansion value of 6.17 ppm*K−1 was measured for nanosized Al2O3/5 wt.% OFA composite. Microstructural characterization of Al2O3‐OFA composites was done by x‐ray diffraction and Raman spectroscopy. Oil fly ash particles were seen to be well dispersed within the alumina matrix. Moreover, the comparative analysis of the nano‐/microsized Al2O3/OFA composites shows that the mechanical and thermal properties were improved in nanosized alumina composites.

Investigations on Tensile and Flexural Characteristics of Fly Ash and Banana Fiber-Reinforced Epoxy Matrix Composites

Polymer matrix composites (PMCs) generally use the inorganic and non-biodegradable materials as reinforcements. This paper presents a PMC with reinforcement of fly ash and banana fiber. The epoxy resin is used as a matrix. This paper investigates the influences of the percentage of fly ash, the percentage of banana fiber and the size of banana fiber on tensile and flexural behaviors of fly ash and banana fiber reinforced epoxy matrix composite. Taguchi’s orthogonal array is used in the design of the experiments in the sample preparations. Analysis of variance (ANOVA) is employed to find the significance of input parameters on tensile and flexural behaviors.

Processing, micro structures and mechanical properties of AZ91E, Sic and fly ash composites: A review

The Mg alloy based composites have a lower density, highest strength, stiffness, best damping capacity, and highest ability which are used in industries. These materials were reinforced with other ceramic particles to create the Metal Matrix Compounds (MMCs). The lightweight materials like Aluminium (Al) and Magnesium (Mg) through hard particles creates metal matrix composites. Moreover, hybrid MMCs are manufactured using a stir casting approach, friction stir processing and examined by Scanning Electron Microscopy (SEM), Optical Microscopy (OM), and Electron Backscattered Drawing (EBSD). These composites are called hybrid metal composites that are reinforced with materials such as nitrides, carbides, and oxides. In this paper, enhancing the consequence of heat treatment and mechanical, microstructure properties of hybrid composites like AZ91E, Silicon Carbide (Sic), and Fly ash are reviewed. Finally, it concludes that hybrid composites parameters are high strength, hardness, low weight, and greatest wear resistance and fatigue than the conventional composites.

An Investigation of Wear Behavior on AA7075 MMC reinforced with CNT and Fly ash Composites

Abstract Hybrid Metal matrix composites are mostly used in various automobile and aerospace application domain due to very high enhanced properties when compared with base alloy. However, this enhancing of base alloy properties is through with the help of addition of dispersoids in various weight percentage with respect to base alloy. This work gives detailed study about wear behavior of AA 7075-T6 grade reinforced with MWCNT and Fly ash having a weight percentage of 1, 2, 3 and 4 by dry sliding test with help of pin on a disc. The specimens were made by stir casting method at optimum conditions. Microstructural and hardness examination also was done to get an overall idea about reinforcement's affirmation. The input parameters such as load (N), speed (rpm), sliding time (min) was predetermined with help of Taguchi L25 orthogonal array and by the main effect of means, S/N ratio plot to identify influence different process parameters in obtaining less weight loss (g), wear rate (mm3/m).

Mechanical properties and wear behavior of fly ash particle reinforced Al matrix composites

In this study, aluminum-based metal matrix composites containing 5, 10, 15, 20, and 25% fly ash particles by weight have been fabricated using a stir casting route. Microstructural observations under an optical microscope suggest that fly ash particles in the cast composites are uniformly distributed throughout the matrix. The mechanical properties such as tensile strength and hardness of the aluminum alloy have enhanced significantly with the addition of fly ash. Wear behavior of base metal and its composite have been studied in dry sliding conditions using a pin-on-disc tribometer. Wear tests have been conducted at three different loads of 9.81, 19.62, and 29.43 N at a constant sliding velocity of 1.3 m s−1. Microstructural observations of worn surfaces and wear debris suggest that wear mechanism in base metal is controlled by adhesion, whereas that for composites is abrasive. The least wear rate has been obtained in Al-10% Fly ash composite. The Al-10% Fly ash is observed to possess an optimum level of mechanical properties and wear behavior.

Experimental investigation of AA2014 alloy with reinforcement of fly ash and SiC hybrid composites by stir casting method

The acceptance of aluminium alloy-based composites in industries in a wide range is because of its high efficiencies and superior properties. To enhance the properties of base alloy hybrid metal matrix composites will have superior performance and better adaptability when comparing with single reinforced composites. In this study, HMMCs will be fabricated by a stir casting process. The effects of reinforcement on the mechanical properties of the composites were investigated by 2, 4 and 6 vol% of ceramic powder along with fly ash. The significant improvement of the composites on the mechanical properties is mainly due to the refinement. Tensile, Impact, and Hardness properties have been studied at room temperature along with the microstructure. The study will increase the probability of Al matrix composites usage for structural applications as lightweight materials.

Effect of production temperature on thermal and mechanical properties of polystyrene–fly ash composites

This study was conducted to produce a novel construction material by using two different types of waste material consisting of fly ash and fragmented polypropylene (PP). These two materials were mixed on various ratios, and samples with smooth surface were obtained by compressing with 50 kg of weight after each mixture is heated on temperatures of 225°C, 250°C, and 275°C and poured into the molds. Thermal and mechanical tests were performed on the prepared samples. As a result, with the evaluation of two waste materials such as fly ash and PP, (i) the contamination caused by the waste materials will be prevented; (ii) as the fly ash rate increases, the thermal properties of samples produced under 225°C of temperature will be enhanced; (iii) as the fly ash rate increases, the thermal properties of samples produced under 225°C of temperature will be enhanced, and PP ratio and production temperature must be high in order to improve mechanical properties; (iv) the produced composite materials bear the low-cost heat, acoustics, and water insulation, while it will also be possible for the same to be used as coating materials on the walls and tiling in the buildings.

An Improved Composite Fly Ash Gel to Extinguish Underground Coal Fire in Close Distance Coal Seams: A Case Study

Fire extinguishing with the superior performance of fly ash composite colloid material is a cost‐effective colloid fire prevention technology. In this paper, a new powder additive (suspending agent (XK‐XJ) and gelling agent) was developed for the existing fire extinguishing technology of fly ash compound colloid. Tests show that the best additions to the fly ash slurry were 0.3% and 0.1∼0.3%, respectively. The grouting technical scheme of adding a suspending agent on the ground and gelling agent downhole was proposed to solve the problems of solid material settlement and blockage in the long‐distance pipeline transportation process. Finally, the optimized fly ash colloid fire prevention and extinguishing technology was successfully applied to the fire control engineering examples of close‐range coal seam groups, and the rationality of the developed powder and its proportion was tested, and the feasibility in coal fire control was tested.

Erosion Analysis on Copper Fly-Ash Composite

In the present study, solid particle erosion behaviour on copper – fly ash composite is studied. Composite with addition of 2.5 (wt.%) fly ash as reinforcement is prepared through powder metallurgy(P/M) technique. Solid particle erosion studies were carried out by varying the input parameters such as erodent velocity and erosion time. The results revealed that addition of fly ash reduced the resistance to erosion.