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Open Journal of Composite Materials 2017年第2期7卷 105-116页

作者： joel hemanth Department of Mechanical Engineering H.M.S. Institute of Technology Tumkur India

In the present research, commercially pure Ti (grade-2) has been diffusion bonded with Ti and Cu plate under static force without any interlayers. The diffusion bonded samples were tested for micro hardness and micro structural analysis through optical microscopy and SEM. It is found from the present investigation that the bonded zone is affected by the processing variables such as bonding time (1 - 2 h), bonding force (250 N), bonding temperature (973 - 1073 K) and surface roughness. Results of the investigation revealed that temperature range of ?973 - 1073 K along with time duration of 1 - 2 hours in vacuum has resulted in a joint having high hardness with minimum pores. Hardness of the bond depends on the grain boundary diffusion at the interface and maximum hardness was achieved in the case of Ti-Cu joints. When Ti-Cu plates were used for bonding at 973 K for 2 hours, Cu-Ti solid solution along with a zone of different intermetallics was formed in the bonded zone. However, at higher temperatures, no continuous zone of intermetallics was found in the bonded region but instead Ti-Cu solid solution appeared.

关键词： Diffusion Bonding Titanium Micro Hardness Surface Roughness Microstructure

Finite Element Wear Behavior Modeling of Al/Al<sub>2</sub>SiO<sub>5</sub>/C Chilled Hybrid Metal Matrix Composites (CHMMCs)

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Materials Sciences and Applications 2011年第7期2卷 878-890页

作者： joel hemanth 不详

This paper describes research on aluminum based metal matrix hybrid composites reinforced with kaolinite (Al2SiO5) and carbon (C) particulates cast using high rate heat transfer technique during solidification by employing metallic, non-metallic and cryogenic end chills. The effect of reinforcement and chilling on strength, hardness and wear behavior are discussed in this paper. It is discovered that cryogenic chilled MMCs with Al2SiO5-9 vol.%/C-3 vol.% dispersoid content proved to be the best in enhancing the mechanical and wear properties. A physically based Finite element (FE) model for the abrasive wear of the hybrid composite developed is based on the mechanisms associated with sliding wear of ductile aluminum matrix of the composite containing hard Al2SiO5 and soft carbon (dry lubricant) reinforcement particles. Finally the results reveal that there is a good agreement that exists between the simulated (FE) values and those of the experimental values, proving the suitability of the boundary conditions.

关键词： Aluminum Composites Casting Hybrid and Wear

Experimental, Mathematical and Finite Element Analysis (FEA) of Temperature Distribution through Rectangular Fin with Circular Perforations

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Modeling and Numerical Simulation of Material Science 2017年第2期7卷 19-32页

作者： joel hemanth H. M. S. Institute of Technology Tumkur India

Fins are the extended surfaces through which heat transfer takes place to keep the surface cool. Fins of various configurations are presently used ranging from automobile engine cooling to cooling of computer parts. Note that in a fin majority of the heat transfer to atmosphere is by convection and therefore in the present research, and importance is given to variation of temperature along the length of the fin which in turn gives rate of heat transfer. In the present research a solid rectangular aluminum fin and the same rectangular fin with different perforations (2, 4, 8 and 10) were compared analytically, experimentally and its validity through finite element analysis for its temperature distribution along the length. From the present research it is observed that the mathematical and FEA for a solid rectangular fin without perforations are converging within ±1°C and rectangular fin with 10 perforations are converging within ±2°C and hence the validity.

关键词： Fin Mathematical Temperature FEA and Perforations

Development of Nickel Alloy Reinforced with Fused SiO2 Chilled Composites and Evaluation of Thermal Properties (Thermal Conductivity &Coefficient of Thermal Expansion) and Temperature Distribution by Finite Element Analysis (FEA)

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Open Journal of Composite Materials 2017年第5期7卷 251-264页

作者： joel hemanth Department of Mechanical Engineering H.M.S.Institute of TechnologyTumkurKarnatakaIndia

This paper presents the results obtained and the discussions made from a series of thermal experiments involving Nickel alloy (ASTM A 494 M) reinforced with fused SiO2, and size of the particles dispersed varies from 80 - 120 μm and amount of addition varies from 3 to 12 wt.% in steps of 3 wt.%. The resulting chilled MMCs are solidified under the influence of copper chill of 25 mm thickness to study the effect of chilling on thermal behaviour. Microstructural studies indicated that the reinforcement distribution is uniform with very good bonding due to chilling effect. Thermal properties were found to decrease significantly with increase in SiO2 content in chilled MMCs. It is concluded from the research that reinforcement content and the temperature has an effect on coefficient of thermal expansion and thermal conductivity of the chilled composite developed. Finite element analysis of the exhaust valve of the IC indicates that chilled Ni alloy composite developed in the present research can be used as alternate material for the existing valve material (Ni-Cr alloy steel). All the tests conducted in this research are in conformance with ASTM standards.

关键词： Nickel Thermal Chill Composite and Conductivity

Heat Transfer Analysis during External Chilling of Composite Material Castings through Experimental and Finite Element (FE) Modelling

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Modeling and Numerical Simulation of Material Science 2014年第1期4卷 1-7页

作者： joel hemanth Mechanical Engineering H.M.S. Institute of Technology Tumkur India

In controlled solidification, one of the important factors that affects heat transfer from the solidifying casting is the resistance offered at the casting/chill interface. In the present investigation, heat transfer analysis during solidification of Al-12%Si (LM 13) alloy is carried out by collecting temperature history of the solidifying casting. The temperature distribution during solidification in the present investigation is obtained using ANSYS multiphysics software and further for comparison. The temperature profiles are also obtained by FE (Finite Element) modelling using the same software. By using a temperature data logger and lab view based software, the temperature data is acquired and processed at every second. The cooling curves obtained are analysed to know the effect of chilling on solidification behaviour of Al-12%Si alloy castings. Finally, it is concluded from the above research that the cooling curves and temperature distribution obtained by FE analysis do not so closely converge with the experimental data due to modelling limitations.

关键词： Solidification Heat Chill Casting Temperature

Tribological Behavior of Copper Chilled Aluminum Alloy (LM-13) Reinforced with Beryl Metal Matrix Composites

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Modeling and Numerical Simulation of Material Science 2019年第3期9卷 41-69页

作者： joel hemanth School of Engineering Presidency University Bangalore India

The present investigation aims at developing copper chilled aluminum alloy (LM-13) reinforced with beryl using stir casting method. Matrix alloy was melted in a composite making furnace to a temperature of about 700°C to which preheated reinforcement particles was added (3 wt.% to 12 wt.% in steps of 3 wt.%), stirred well and finally poured in to an AFS standard mold containing copper end chills of different thickness (10, 15, 20 and 25 mm) placed judiciously for directional solidification. The resulting chilled composites were subjected to microstructural, XRD, mechanical properties (strength and hardness) and tribological *** of the microstructural and XRD analysis indicate that the chilled castings were sound with good distribution and presence of all the particles. The bonding between beryl reinforcement and Al alloy matrix (LM-13) leads to excellent isotropic properties without?any shrinkage or microporosity. Mechanical characterization indicates that both strength and hardness were maximum in the case of copper chilled MMC containing 9 wt.% and 12 wt.% reinforcement respectively. Strength and hardness of chilled MMC are found to increase by 9.88% and 16.66% as compared against the matrix alloy. It is observed that because of the ceramic (beryl) reinforcement in aluminum alloy, the wear resistance of the chilled composite developed has increased with increase in reinforcement content. At lower load, chilled MMCs exhibited mild wear regime with high coefficient of friction and at higher loads they exhibited severe wear with better wear resistance compared to un-chilled composite. It is observed that the increase in mechanical properties and wear resistance are due to incorporation of beryl reinforcement, the effect of chilling that has resulted in grain refined microstructure with good bonding of the matrix and the reinforcement.

关键词： Aluminum Beryl Composite Tribology

Effect of Metallic, Nonmetallic, Water Cooled and Cryogenic Chills on Pearlite Content (PC), Eutectic Cell Count (ECC) and Grain Size (GS) of Hypo Eutectic Nickel Alloyed Cast Iron

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Modeling and Numerical Simulation of Material Science 2017年第1期7卷 1-18页

作者： joel hemanth Mechanical Engineering H.M.S. Institute of Technology Tumkur India

This paper presents the results obtained, deductions made from solidification behaviour and a series of micro structural studies such as pearlite content, eu-tectic cell count and grain size of hypoeutectic gray cast iron which was sand cast (CO2 moulding) using metallic, nonmetallic, water cooled and subzero (cryogenic) end chills. Hypo-eutectic cast irons containing C 3.42, Si 2.4 and Ni 1.5 with impurity contents (S, P, Mn etc.) were solidified unidirectionally in an American Foundrymen Society (AFS) standard mould, the end of which was provided with different end chills to study the effect of chilling during solidifi-cation. The melts were inoculated with 0.3% Fe-Si to promote graphitization. It was observed that the transition from one structure to another is more gradual than normally obtained in the structure of cast irons solidified mul-ti-directionally in a sand mould at room temperature. Austenite dendrite interactions were shown to be a major factor in determining the microstructure, in which the higher dendrite reaction leads to changes in DAS, ECC and GS. It is observed that, the number of eutectic cells is an index of graphite nucleation and the effect of these on structure, since the eutectic cells are developed on the graphite nuclei during solidification.

关键词： Cast Iron Chill Solidification Pearlite Eutectic and Grain Size

Microstructure, Mechanical Properties (Strength and Hardness) and Wear Behavior of Chilled Aluminum Alloy (LM-13) Reinforced with Titanium Carbide (TiC) Metal Matrix Composites

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Journal of Materials Science and Chemical Engineering 2019年第7期7卷 55-66页

作者： joel hemanth K. Arasukumar School of Engineering Presidency University Bangalore India Department of Mechanical Engineering Gopalan College of Engineering and Management Bangalore India

This paper deals with the production of aluminum alloy (LM-13) reinforced with titanium carbide (TiC) chilled composites subject to different chilling rates to study the effect of chilling on microstructure, mechanical and tribological behavior. Metallic and non-metallic chills (25 mm thick) were used in this investigation. The specimens taken from casting blocks were tested for their microstructure, strength, hardness and wear behavior. It was found in the present investigation that chilling rate and addition of TiC reinforcement (3 to 12 wt% in steps of 3 wt%) have improved both mechanical properties (strength and hardness) and wear resistance of the composite developed. Out of the chills used, copper chill was found to be good in improving mechanical properties because of its high Volumetric Heat Capacity (VHC). It is concluded from the above investigation that type of chill and hence chilling rate, reinforcement content have an effect on mechanical properties wear behavior.

关键词： Wear Strength Hardness Chill Solidification

Corrosion and Wear Behavior of Nano-Zirconium (Zr) Coated Commercial Grade Cast Iron by Sol-Gel and Plasma Spray Process

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Open Journal of Composite Materials 2019年第2期9卷 57-71页

作者： joel hemanth Sara Sowjanya Steevenson School of Engineering Presidency University Bangalore India Visveswaraya Technological University (VTU) Belgaum India

Hard facing with Nickel/cobalt based alloys for steel substrates are widely used for high temperature and pressure applications in chemically reactive environments due to their good corrosion and wear resistance properties. In the present research, the ceramic material, i.e., zirconium, is coated on a hypoeutectic cast iron substrate to improve its corrosion and wear resistance. The substrate was coated with zirconium by sol-gel process as well as by the plasma spray process for comparison purpose. Results of the research indicated that the successful deposition of zirconium on the cast iron substrate by sol-gel deposition technique had improved both corrosion and wear resistance of cast iron. SEM analysis revealed that the coating was denser without any internal cracks indicating the soundness of deposition. Also, sol-gel process of coating indicated better wear resistance as compared with plasma spray coated cast iron. Thus, zirconium coating on the substrate has made cast iron sound (without any surface defects) along with excellent corrosion and wear resistance properties. This has made cast iron suitable for structural and automotive applications.

关键词： Sol-Gel Coating Wear Corrosion Zirconium Cast Iron

Finite Element Analysis (FEA) and Thermal Gradient of a Solid Rectangular Fin with Embossing’s for Aerospace Applications

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Advances in Aerospace Science and Technology 2018年第3期3卷 49-60页

作者： joel hemanth K. B. Yogesh Presidency University Bangalore India JSS Academy of Technical Education Bangalore India

Fins are the extended surfaces through which heat transfer takes place by conduction and convection to keep the base surface cool. Fins of various configurations are presently used ranging from automobile engines to cooling of chip in a computer. Fins used presently are solid with different shapes but in the present research such solid fins are compared with solid fins having maximum of 10 numbers of embossing’s that further increases the surface area for maximum heat transfer. Importance in this research is given to variation of temperature along the length of the fins which in turn gives rate of heat transfer. Thus this research is under taken to increase the efficiency of fins (by extracting heat from the base surface) which is highly demanded today for air cooled engines, compressors, refrigerators etc. In the present research, SOLID70 element and SURF152 elements are used for FE analysis. Methodology involves 3D rectangular fin modelling and meshing, creation of surf elements for the modeling, applying the boundary conditions and source temperature, applying the material property (aluminum) to obtain the steady state thermal contours. FEA results are finally compared with analytic and experimental values for validity. In the present research, a solid rectangular aluminum fin and the same rectangular fin with 2, 4, 8 and 10 embossing’s were compared through finite element analysis for its temperature distribution along the length. FEA analysis of the present research showed that fins having embossing’s were more efficient compared to that a simple solid fin. Hence it is concluded from the present research that embossing’s at preferred locations further increases the rate of heat transfer. From the present analysis it is concluded that the mathematical and FEA for a solid rectangular fin without embossing’s are converging within ±1.2°C and rectangular fin with 10 embossing’s is converging within ±1.4°C and hence the validity.

关键词： Fin FEA Temperature Embossing and Surface