EFFECT OF WEIGHT PERCENTAGE OF SILICON CARBIDE ON THE MECHANICAL PROPERTIES AND MICROSTUCTURE OF ALUMINIUM COMPOSITES

Abstract

 The effects of silicon carbide (SiC) addition on the mechanical properties and microstructure of aluminum metal matrix composites are investigated. Aluminum alloy samples with 2%, 4%, 6%, 8%, and 10% SiC composition by weight were fabricated by casting along with a control sample consisting only the Aluminum matrix. The samples were machined to standard specimen for the purpose of Mechanical testing which includes tensile test, hardness test, impact toughness as well as micro- structural examination. The results of the investigations illustrate that the tensile property of the composite is enhanced when the SiC additions are augmented. The 10wt% SiC specimen showed a maximum ultimate tensile strength of 171.85 MPa and fracture stress of 170.59 MPa. Hardness also improved proportionally with increased SiC reinforcement, 135.4 Vickers Pyramid Number (HV) was observed for 10wt%compared to 100.2 HV for the control the specimen. However, the impact energy absorbed before fracture by specimens decreased as the SiC reinforcement increased across the specimens. The result shows sufficient Silicon Carbide reinforcement can be applied in Aluminium composites for applications requiring improved strength and lower Impact toughness. Micrographs detected refined grains and finely dispersed strengthening precipitates for higher SiC compositions which accounts for the superior strength. Spectrometry analysis for control specimen verified that silicon was the key alloying element. The 10% SiC composite displayed an optimal balance of enhanced strength and hardness coupled with substantial ductility.