Synthesis of hyper eutectic rapid solidified Al Si alloys and evaluation of their mechanical metallurgical and tribological properties under dry lubricated and coated conditions

Abstract

Over the last decade, there has been rapid development in the application of aluminum-silicon alloys, especially in the automotive industry. This is attributed to their high wear resistance, low coefficient of thermal expansion, reduced weight, high strength-to-weight ratio, and low density. The advancements in their application make the research of their tribological and mechanical properties crucial. In this current study, Aluminum (Al)-based alloys with 16%, 17%, and 18% silicon (Si) were processed using rheo stir casting and new rheo stir-squeeze casting techniques. Compositional studies and tensile investigations of various samples with similar compositions have shown a near-uniform distribution of Si in the processed Al-Si alloys. Hardness and tensile tests were conducted using a Brinell hardness tester and a Tensometer. The hardness, yield strength, and ultimate tensile strength values for the 17wt% Si alloy are superior to those for other percentages (16wt% and 18wt%). In contrast, the tribological behavior of the H-Al-17Si alloy was studied using a High-Frequency Linear Reciprocating Tribometer under different loading conditions (10-50N) with dry, lubricated (SAE15W40), and (DLC-Star) coated dry conditions. Resistance to friction and wear increased with lubricated and coated sliding conditions. The worn surfaces were analyzed using SEM, an advanced metallurgical microscope, and an AFM profilometer. newline newline