Influence of Casting Die Diameter Size on Microstructure and Mechanical Fractrography of Al-7Si Alloy with Flyash and Graphite Composites

Abstract

MMCs exhibit increased modulus, strength, and fatigue strength. In MMCs, reinforcements can either be discontinuous or continuous or a combination of both. Owing to lower aspect ratio, and random orientation of the reinforcements, discontinuously reinforced composites exhibit comparatively higher isotropic properties than composites that are continuously reinforced. In the current research an attempt has been made to carry out experiments on Al-7Si and Fly ash and Graphite hybrid composites which were fabricated in steps of 3 wt.% of Flyash with 3 wt.% of Graphite and 3 wt.% of Flyash with 5 wt.% of Graphite for 25mm and 75mm diameter dies. Microstructural characterization of the specimens prepared following SEM, XRD, and EDS. Mechanical properties like hardness, yield strength, and ultimate tensile strength were evaluated as per ASTM standards. The composites prepared in 25 mm cast iron die were exhibited superior mechanical properties as compared to the composites prepared in the 75 mm diameter cast iron die. Further, with the addition of fly ash and graphite particles mechanical properties of Al-7Si alloy were improved.