Effects of Yttrium Contents on the Structure, Physical, and Mechanical Properties of Al-12wt%Si Eutectic Alloy System
Keywords:
yttrium, Al-Si alloy, structure, physical and mechanical properties.Abstract
This research investigated the effects of yttrium contents on the structure, physical and mechanical properties of Al-12wt%Si eutectic alloy system. Yttrium was added in concentrations of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.25 and 1.50wt% respectively. The samples were developed using permanent die casting method and machined to the required dimensions for the structural analysis, mechanical and physical properties tests. The mechanical properties test results confirm that the mechanical properties of Al-12wt%Si eutectic alloy system are increased with yttrium addition, with ultimate tensile strength (UTS) of 232MPa and percentage elongation of 36.7% at yttrium content of 0.7wt%. Also, impact strength of 4J and hardness of 56HBW were achieved at yttrium content of 0.8wt% and 1.0wt% respectively. Yttrium addition to Al-12wt%Si eutectic alloy system increased the electrical resistivity with maximum increase observed at 0.3wt%Y (321.6 x10-6Ωm). The improved mechanical properties are attributed to the structural modification of the silicon platelets.
