Developing high performance mechanical properties at elevated temperature in squeeze cast Al-Cu-Mn-Fe-Ni alloys

Microstructures and mechanical properties of T7 heat-treated Al-5.0Cu-0.6Mn-1.0Fe alloys with different Ni content prepared via squeeze casting were studied using tensile testing, image analysis, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results show that the mechanical properties of squeeze cast Al-5.0Cu-0.6Mn-1.0Fe alloys were improved obviously when the Ni content was increased from 0.5 wt% to 1.5 wt%. This improvement can be attributed to the increase in heat resistance of the Al9FeNi and Al3CuNi phases, the decrease in copper-rich Al7Cu2Fe phases and porosities, and the increase of T (Al20Cu2Mn3) particles in the alpha(Al) matrix. Ultimate tensile strength (UTS), yield strength (YS), and elongation (EL) values of the squeeze cast Al-6.0Cu-0.6Mn-1.0Fe-1.5Ni alloy were as high as 152 MPa, 142 MPa, and 23.7%, respectively, at an elevated temperature of 300 degrees C. These values are higher than those of the majority of commercially available heat resistant aluminum alloys, and this indicates the high potential for developing recycled squeeze cast Al-Cu alloys.