Investigation of the Microstructure and Mechanical Characterization of an Aluminum-12 wt% Silicon Alloy Processed using Die and Centrifugal Casting Processes

The study examined eutectic Al–Si alloys containing 12% silicon, produced by die casting and centrifugal casting methods. Specimens were fabricated from cast billets in accordance with ASTM standards for the purpose of evaluating mechanical and tribological characteristics. The surface analysis showed an even distribution of the secondary phase in the aluminum matrix, with both spherical and needle-like features. The sample density was measured using the water displacement method, resulting in densities of 2.6345 ± 0.0055 gr/cm³ for the as-cast specimens and 2.6428 ± 0.0008 gr/cm³ for centrifugally cast specimens. The bulk hardness of the samples was measured using Brinell hardness instrument, while quasi-static tensile equipment was utilized to assess the ultimate tensile strength (UTS) of both as-cast and centrifugally cast eutectic alloys. The as-cast eutectic alloy’s ultimate tensile strength (UTS) was determined to be 152.528 ± 4.657 MPa, whereas the UTS of the centrifugally cast eutectic alloy was recorded as 156.005 ± 7.373 MPa. In addition, the tribological performance was evaluated using pin-on-disk wear tests, which showed that the as-cast eutectic alloys had better wear resistance than those formed via centrifugal casting. The differences in the characteristics of the eutectic alloys between the two casting procedures are caused by unique mechanisms that enhance the strength of each casting process.