V. Kavimani

Investigations on the effect of friction stir processing on Cu-BN surface composites

ABSTRACT The main aim of this investigation focuses on fabrication of copper surface composites through friction stir processing (FSP) reinforced with boron nitride (BN) particles of varying volume fractions (5%, 10%, and 15%). Surface composites developed through single pass FSP were characterized for its microstructural, mechanical and tribological properties. Microstructural characterization indicated that developed surface composites were of good quality with reduced grain size and the SEM characterization confirmed good bonding between copper matrix and BN with uniform dispersion. Micro hardness survey of the developed surface composites showcased minimal deviation in the stir zone with increased trend in respect to the volume fraction of BN. The ultimate tensile strength, yield strength and percent elongation of FSPed composites was found to have reduced when compared with that of pure copper. BN dispersion in surface composite was effective in reducing the ductility and so maximum volume percent (15%) of BN dispersed composite prompt to have higher strength. The wear rate and friction coefficient of the developed surface composite was found decreasing with respect to increase in the dispersion of BN. Amongst the FSPed copper surface composite, specimen with 15 vol% of BN has shown the least wear rate with low coefficient of friction.

Doping Effect of SiC over Graphene on Dry Sliding Wear Behaviour of Mg/SiC@r-GO MMCs and its Surface Characterization

In this research, solvent based powder metallurgy is used to develop Silicon Carbide (SiC) doped reduced Graphene Oxide(r-GO) reinforced magnesium composite. SiC was doped with r-GO with varying wt.% (10 & 20) by adopting hydrothermal method. Influence of SiC doping over r-GO in wear resistance of developed composite was investigated by pin on disc method. Taguchi based Artificial neural network (ANN) was used to attain optimal wear parameter and to study the influence of wear parameter by developing a mathematical model. From ANOVA results it has been observed that wt.% of reinforcement play an important role in governing the wear loss of fabricated MMC. The developed ANN model exhibits accuracy of about 99.9% when subjected to predict the wear loss. Formation of tribolayer and plastic deformation were notified from worn surface morphology, thus evidencing for the occurrence of delamination and oxidation wear.

Effect of friction stir processing and hybrid reinforcements on copper

ABSTRACT In this research, a copper based surface composite was fabricated through dispersing hybrid composite particles onto its surface through friction stir processing (FSP) technique. Optical micrographs and scanning electron microscopy images indicates finer refinement of grains and particles dispersion into matrix along with its bonding and particle separation. As per the outcomes of microhardness analysis, hardness of the developed surface composite shows increment with increase in dispersion of volume fraction of hybrid particles. Strength of the developed copper surface composite exhibited a positive trend with introduction of hybrid reinforcement particle onto the surface of the composite but yet again ductility reduced. Wear resistance of the composite increased with reinforcement addition and the same was supported through worn out surface morphology. Fluctuations in friction coefficient value reduced with increase in particles, as for the presence in BN particles while the average frictional coefficient value was observed increasing. A reduction in corrosion rate was observed with increase in reinforcement particle dispersion onto copper matrix through FSP.