Rolling Texture Development in Aluminum-Zinc Solid Solutions

Abstract

Rolling textures in face-centered cubic polycrystalline metals tend to transform from so-called pure metal to alloy textures with increasing stacking fault energy, so deformation texture correlates directly to stacking fault energy. As a 30th anniversary tribute to the classic copper-brass study by Hirsch and Lücke [1988], we recast the problem for binary aluminium alloys with 1, 10, 34 and 62wt.%Zn. Zinc (Zn) has a very high solid solubility in Al of up to 65at.% at 381°C, but at lower temperatures the Zn solid solution is unstable and can precipitate out or decompose spinodally. Current understanding is that Zn has no effect on the stacking fault energy of aluminum, so a priori, rolling of different Al-xZn alloys should result in no variation in deformation texture. Cast ingots were solutionized and promptly rolled 75 and 90% by multiple passes. X-ray texture pole figures were measured at the mid-plane of the rolled sheet, and the texture components calculated from the crystallographic orientation distribution function. Results show a decrease in {112}<11-1> and increase in {011}<21-1> with Zn content but uncorrelated changes in {123}<63-4> components. Bird’s eye - like microstructural features observed in the high Zn containing alloys at 90% reduction were {011}<21-1> and resemble those observed by other researchers in severely rolled brass, Al-4.5Mg and 316L.