Squeeze-cast Al-xZn-3Cu alloys exhibiting high strength, ductility, and wear resistance

In this work, we determined the feasibility of fabricating Al-xZn-3Cu cast alloys with a balanced combination of strength, ductility, and wear resistance. We found that when >30 wt% Zn is added to Al, cast alloys with properties exceeding those of conventional Al-xSi-based cast alloy counterparts are formed. For example, the Al-40Zn-3Cu alloy, when cast under a pressure of 100 MPa, exhibits a high tensile strength (~470 MPa) and ductility (~9%) even without melt modification and optimized heat treatment. We attribute these improved properties to solution-hardened fine α-Al grains and a networked skeleton of grain boundary phases formed during rapid solidification. The Al-40Zn-3Cu alloy also exhibits a low melting temperature (~564 °C), better fluidity, and better wear resistance than currently used Al-xSi-based alloys; hence, the alloy developed herein would be suitable for producing high-integrity structural parts via squeeze casting.