Microstructure and Mechanical Properties of Hypo and Hypereutectic Al-Si Alloy Processed through Die and Centrifugal Casting

Abstract

The hypo and hypereutectic alloys of Al-Si for the silicon percentage of 6 and 18 % Si respectively produced through die casting and centrifugal casting for the research work. The samples of ascast and centrifugal casting from the casted billets prepared as per the ASTM standards for the microstructure analysis, to determine mechanical and tribological properties. The surface topography of the samples revealed spherical and needle morphology and uniform distribution of the secondary phase within the Al matrix material. The density of the samples are measured using water displacement method and density of the ascast and reciprocating samples of hypoeutectic alloy were found to be reported as2.6793± 0.0075and 2.6392 ± 0.0016 g/cc respectively, whereas the density of hypereutectic ascast alloy is reported as 2.6265 ± 0.002and centrifugal hypereutectic alloy is 2.6226 ± 0.0086 g/cc. The micro hardness of the ascast and centrifugal casting hypo and hypereutectic Al-Si alloys are measured using Vickers hardness testing machine. The ultimate tensile strength of the ascast and centrifugal casting of both hypo and hyper eutectic alloys were carried out using quasistatic tensile test. The UTS of ascast hypoeutectic alloys is 148.552 ± 4.774 MPa and centrifugal casting hypoeutectic alloy is 154.512 ± 7.949 MPa.The UTS of hypereutectic ascast and centrifugal casting alloys are reported as 140.40 ± 32.23 and 159.807 ± 21.145 MPa respectively. The variations in the properties of hypo and hypereutectic alloy of ascast and centrifugal Al-Si alloy could be attributed to different strengthening mechanisms of the alloys.