Effects of Copper Content on Microstructure and Mechanical Properties of Al–Mn Eutectic Alloys

Alloying elements in aluminium have further been improving the strength and stiffness properties that provide superior compared to other metals. Especially the alloying of copper, silicon and manganese in aluminium alloys improves the casting ability, as well asincrease strength and stiffness properties. In the literature, it is the attention that the especially studies on eutectic composition are abundant. Because the eutectic composition has a lower melting point than the melting point of the other elements, both obtains two separate solid phases from a single liquid phase and aluminium alloys increasing of fluidity. In this work, in order to investigate the effect of copper content on the microstructure and mechanical properties of the Al-Mn eutectic alloy, 5 percentby weight of copper was added to the base alloy. Al–2Mn–5Cu (wt.%) alloys were prepared in a graphite crucible under vacuum atmosphere. The samples were directionally solidified upward at a constant temperature gradient (7.1 K/mm) and different growth rates (from 8.3 μm/s to 978 μm/s) by using a Bridgman type directional solidification furnace. The primary dendrite arm spacing, microhardness and tensile strength of alloys were measured from directionally solidified samples. The effects of copper content on the microstructure and mechanical properties of Al–Mn eutectic alloys were investigated and the relationships between them were experimentally obtained. The results obtained in the present work were compared with the previous experimental results.