COMPARATIVE STUDIES ON THE EFFECTS OF VARIOUS PARTICULATES REINFORCEMENTS ON THE MECHANICAL AND WEAR PROPERTIES OF ALUMINUM ALLOY (AA2618) MATRIX COMPOSITE

Abstract

Studies on the effects of various particulate reinforcements on the mechanical and wear properties of aluminum alloy (AA2618) matrix composites have been carried out. Compo-casting method was used in which 0vol%, 5vol%, 10vol%, 15vol%, 20vol%, 25vol% and 30vol% each of AA2618/SiC, AA2618/TiC and AA2618/fly ash composites were made.  The cast specimens were machined to different dimensions for various mechanical and wear resistance tests. The mechanical tests done were ductility, hardness, yield strength, ultimate tensile strength, Young’s modulus and density. Pin on disc computerized sliding wear resistance tests on the composite samples were also done. The results of mechanical characterization revealed that increase in vol% addition of these particles in the matrix of the alloy resulted in corresponding increase in all the mechanical property tests except the ductility that decreased with increase in vol% addition of the particles. AA2618/SiC composite recorded the highest value while the least value was shown by AA2618/fly ash composite. It was also discovered that addition of fly ash particles in the matrix of AA2618 recorded significant increase in strength without unduly compromising the ductility. The obvious facts of these developments are that these particles enhanced the mechanical properties of this alloy through dispersion strengthening by infringement on dislocation movements within the internal structure of the composite with corresponding increase in dislocation density. Sliding wear tests of these samples showed that there were improvements in wear resistance of the composites as a result of the presence of these particles within the matrix of the alloy. 20vol% addition of SiC and TiC and 25vol% addition of fly ash gave the best results of mechanical tests.  Beyond this, segregation started and mechanical strength was reduced. Finally these particulate reinforcement’s enhanced mechanical and wear properties of the composites with SiC particles recording the best result. Therefore, they are recommended for use in industrial applications as a result of their enhanced mechanical and wear properties.