Microstructures and Mechanical Properties of Binary Al-Zn Alloys Fabricated by Casting and Heat Treatment

Binary Al-Zn alloys with different Zn contents were fabricated by casting and heat treatment. Analysis of mechanical properties showed that the hardness and tensile strength of Al-Zn alloys increased with increased Zn content, with the post-heat treatment hardness and ultimate tensile strength of Al-49Zn alloy reaching as high as 152 HV and 330 MPa, respectively. Meanwhile, the plasticity and toughness of Al-Zn alloys decreased with increased Zn content. Solid-solution strengthening was the main strengthening mechanism for Al-Zn alloys, and Orowan strengthening was also observed in Al-49Zn alloy. The fracture mode of Al-20Zn and Al-35Zn alloys was ductile, whereas Al-20Zn alloy showed good impact toughness. This work provided a basis for further improving the cast component design of the Al-Zn-X system.