Advanced Materials Letters

Abstract

In a quest for developing new lightweight metal alloys that can perform excellently at elevated-temperatures (from 300°C to 400 °C), a ternary eutectic Al-Cu-Si alloy was exploited to gain a deeper understanding of the alloy system and its suitability for high temperature applications. The studied alloys, with chemical composition of Al-27%Cu-5%Si (by weight percent) with Ni addition in the range of 0 to 1.5%wt, were cast in a rapid solidification casting technique. The solidification characteristics of the alloy was studied using the Thermo-Calc software. Microstructures were characterized in a scanning electron microscope coupled with energy dispersive spectrometry (SEM-EDS). Finally, the elevated-temperature tensile properties of the alloys were investigated. Comparing the microstructures and mechanical properties of the Al-Cu-Si(-Ni) alloys with conventional A319 Al- alloy, the refined microstructure with dispersed Ni intermetallic particles formed in the as-cast Al-Cu-Si(-Ni) alloys delivers improved elevated temperature properties. In particular, the yield strength and ultimate tensile strength of the new alloy with 1.5% Ni at 400˚C were observed to be 220% and 309% higher, respectively, than for conventional A319 reference alloy.