Microstructure and Properties of 7050-T74 Aluminum Alloys with Different Zn/Mg Ratios

Aluminum alloy 7050-T74 with varying zinc-to-magnesium (Zn/Mg) mass fractions was synthesized using melt casting and hot extrusion techniques. This study investigated the influence of different Zn/Mg ratios on the microstructure, mechanical properties, and corrosion resistance of the alloy. Light microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), tensile testing, and corrosion testing were employed as analytical methods. The findings indicate that as the Zn/Mg ratio increases from 2.36 to 3.84, the proportion of low-angle boundaries (LABs) within the alloys initially rises and then decreases, achieving a balance between high strength and favorable elongation. Specifically, at a Zn/Mg ratio of 2.72, the alloy exhibits a tensile strength of 641 MPa, a yield strength of 609 MPa, and an elongation of 10.1%. Additionally, increasing the Zn/Mg ratio to 2.90 slightly reduces intergranular corrosion resistance while enhancing exfoliation corrosion resistance.