R. Keshavamurthy

Studies on Parametric Optimization for Plasma Sprayed Fly Ash - Al2O3 Composite Coatings

Present investigation deals with the effect of varying process parameters on the characterization of plasma sprayed fly ash - Al2O3 composite coatings using Taguchi’s experimental design method to conduct experiments and optimization of process parameters. Parameters such as standoff distance, powder feed rate and current density were considered for the optimization of bond strength, porosity and hardness. The significance of the parameters and their optimum level is determined by using ANOVA. Experiments were carried out to validate the effect of optimum process parameters on response characteristics and found that selected optimal combination of process parameters is able to achieve the best results.

Effect of Thermo-Mechanical Processing and Heat Treatment on the Tribological Characteristics of Al Based MMC's

This paper reports on effect of forging and Heat Treatment on Tribological characteristics of aluminium alloy-silicon nitride. Cast aluminium alloy and composite were subjected to open die hot forging process. Alloy and its composites were examined to characteristics hardness and wear test under both primary and secondary processing conditions. Effect of heat treatment on hardness and tribological behaviour were also studied. Microstructure shows even spreading of particles in cast & forged conditions. hot forged alloy and composite shows a noticeable improvement in wear resistance and COF compare to their primary counter parts. Heat treatment has a considerable effect on hardness, friction and wear characteristics of composites.

Mechanical Characteristics of Hot Forged Al6061-Al2O3 Composite

Commercially available Al6061 alloy added with 5wt% of alumina particles was developed by liquid metallurgy route. Cast aluminum alloy and composite were hot forged. Microstructure, hardness and strength behavior of forged alloy and composite were investigated. Optical micrograph examination confirms the homogeneity in the dispersion of alumina particles. Addition of alumina particles increased the hardness and tensile strength by 21% and 18% respectively.

Tribological Characteristics of Al6061-TiC Composite Synthesized by In Situ Technique

Al6061-TiC in-situ composite was developed using hexafluorotitanate salt and graphite powder. Microstructure studies, hardness and dry sliding friction and wear behavior were investigated for both base alloy and in-situ composite. Friction and wear tests were performed at the normal load and sliding speeds in the range 20-100N and 0.314-1.57m/s respectively. For a given TiC content, coefficient of friction was lower than base alloy for all the loads and sliding speeds. A tremendous improvement in the wear resistance of the composite was found when compared with base alloy.

Optimization and Analysis of Laser Beam Machining Parameters for Al7075-TiB2 In-situ Composite

The paper focuses on laser beam machining (LBM) of In-situ synthesized Al7075-TiB2 metal matrix composite. Optimization and influence of laser machining process parameters on surface roughness, volumetric material removal rate (VMRR) and dimensional accuracy of composites were studied. Al7075-TiB2 metal matrix composite was synthesized by in-situ reaction technique using stir casting process. Taguchis L9 orthogonal array was used to design experimental trials. Standoff distance (SOD) (0.3 - 0.5mm), Cutting Speed (1000 - 1200 m/hr) and Gas pressure (0.5 - 0.7 bar) were considered as variable input parameters at three different levels, while power and nozzle diameter were maintained constant with air as assisting gas. Optimized process parameters for surface roughness, volumetric material removal rate (VMRR) and dimensional accuracy were calculated by generating the main effects plot for signal noise ratio (S/N ratio) for surface roughness, VMRR and dimensional error using Minitab software (version 16). The Significant of standoff distance (SOD), cutting speed and gas pressure on surface roughness, volumetric material removal rate (VMRR) and dimensional error were calculated using analysis of variance (ANOVA) method. Results indicate that, for surface roughness, cutting speed (56.38%) is most significant parameter followed by standoff distance (41.03%) and gas pressure (2.6%). For volumetric material removal (VMRR), gas pressure (42.32%) is most significant parameter followed by cutting speed (33.60%) and standoff distance (24.06%). For dimensional error, Standoff distance (53.34%) is most significant parameter followed by cutting speed (34.12%) and gas pressure (12.53%). Further, verification experiments were carried out to confirm performance of optimized process parameters.

Influence of Hot forging on Tribological behavior of Al6061-TiB2 In-situ composites

Al6061-TiB2 metal matrix composite was fabricated by stir casting technique via in-situ reaction, using mixture of Al6061 alloy, Potassium tetraflouroborate salt (KBF4) and tetraflourotitanate (K2TiF6). The cast composites were processed to hot forging, SEM studies; X- ray Diffraction studies (XRD), Microhardness and Dry friction and wear tests. Pin on disc type machine was used to perform tribological tests over a load range of 20-100N and sliding velocities of 0.314-1.57m/s. SEM and XRD studies confirms formation of fine in-situ TiB2 particles. Composites exhibit higher Microhardness, improved wear resistance and Lower COF with formation of TiB2 particles when compared with the unreinforced alloy. Compared to cast alloy and its Composites, forged alloy and its composites show superior Tribological behavior under similar test conditions.

Estimation of Tribological Behavior of Al2024-TiB2 In Situ Composite Using GMDH and ANN

This paper reports on prediction and comparison of tribological behavior of Al2024-TiB2 in-situ metal matrix composites using Group Method Data Handling Technique (GMDH) and Artificial Neural Network (ANN). Experiments were carried out using Pin-On-Disc type testing machine as per ASTM standards by varying the loads and sliding velocities. Two responses namely coefficient of friction and wear rates have been considered for each experiment. It was found that, ANN is the most reliable and accurate technique for prediction compared to GMDH.

Experimental Investigations on Wire EDM of Al7075-TiB2 In Situ Metal Matrix Composite

This paper focuses on optimization of process parameters for wire electric discharge machining (WEDM) of In-situ Al7075-TiB2 metal matrix composites processed by stir casting technique using Taguchi method of experimental design. The effect of pulse-on, pulse-off, current, and bed speed on dimensional accuracy, surface roughness and volumetric material removal rate (VMRR) have been investigated keeping voltage and flush rate constant. L27 orthogonal array of Taguchi technique was used for experimental trials. The optimum process parameters have been identified. Significant process parameters were identified from the analysis of variance (ANOVA). Further, verification experiment has been carried out to confirm the performance of optimum process parameters.

Mechanical Properties of Al7075-SiC-TiO 2 Hybrid Metal Matrix Composite

Appropriate combination of matrix and reinforcement leads to a new material that can be made to exactly meet the requirements for a specific application. The scope of this research includes developing Aluminium based hybrid composite material using Al7075 as matrix and SiC and TiO2 as reinforcement by stir casting method. Silicon carbide possesses high density, high hardness, high fracture toughness and excellent strength over a wide range of temperature and titanium dioxide posses’ good thermal shock and chemical resistance. Developed composites were subjected for microstructure and SEM/EDAX studies and hardness and tensile characterization. Microstructure shows, SiC & TiO2 particles are uniformly distributed throughout the matrix. Mechanical studies of Al7075 alloy and Al7075 + SiC + TiO2 have exhibited higher hardness and tensile strength with excellent bond between aluminium alloy and hybrid reinforcements.

Studies on parametric optimization for abrasive water jet machining of Al7075-TiB2 in-situ composite

The study focuses on optimization and determination of significant process parameter for Abrasive Water Jet Machining of Al7075-TiB2metal matrix composite. Al-TiB2 metal matrix composite is synthesized by stir casting using in-situ technique. Optimization of machining parameters is done using Taguchis L25orthogonal array for the experimental trials, with cutting speed, stand-off distance and Abrasive Flow rate as input parameters at five different levels. Analysis Of Variance (ANOVA) method is used for identifying the effect of machining parameters on volumetric material removal rate, surface roughness and dimensional accuracy. Then the results are validated by conducting verification experiments.