Microstructure development and tensile properties of ADC12 Al-Si alloy with different content of Praseodymium (Pr)

Abstract

Vehicle weight reduction is very important due to economic and environmental needs. To this end, the automotive and aerospace industries use aluminum cast alloys extensively. The needle-like/flake-like eutectic silicon in the cast structure decreases percentage of elongation, fracture toughness, and fatigue resistance. Therefore, casting units use eutectic silicon modification extensively on molten aluminum-silicon alloys to transform flake-like silicon to fibrous silicon, improving its properties. Hence, the current research aims to investigate the effect of praseodymium (Pr) addition on the microstructure changes and the tensile properties of the ADC12 Al-Si alloys. The ADC12 Al-Si alloy with different percentages of Pr (0.1, 0.3, 0.5, and 1.0 wt. %) were prepared by gravity casting technique. The microstructural analysis and tensile properties were conducted using an optical microscope (OM), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) analysis and tensile test. The results showed that ADC12 Al-Si alloy treated with 0.5 wt. % of Pr demonstrates the lowest grain size and aspect ratio composition as well as highest tensile results compared to other fabricated alloys. The eutectic Si grain size decreases at 0.5 wt. % Pr where the value of aspect ratio is the lowest. There is an increment in ultimate tensile strength (UTS) and elongation by 20.05 % and 40.35 %, respectively, with the addition of 0.5 wt. % Pr.