Effect of pre-rolling aging treatment on evolutions of the microstructure and the texture of aluminium alloy 7005 subjected to heavy cold rolling.

Abstract

Aluminium alloy 7005 is widely used for structural purposes because of its attractive properties such as good weldability and age-hardening capability. However, since the workability of this alloy falls after a short period of natural aging, the application of cold rolling for the production of strain-hardened sheets of this alloy is a challenge. Two solutions proposed to overcome this challenge are as follows: (a) immediate rolling of the alloy after solution treatment and (b) rolling of the alloy after artificial aging. However, there is no comprehensive study comparing the effect of pre-rolling aging treatments on the evolutions of microstructure and texture of the alloy through heavy cold rolling. This subject is the aim of the present study. For this purpose, different pieces of the alloy are subjected to three different heat treatments before rolling, and afterward, they are rolled to obtain a thickness reduction of 80%. Scanning electron microscopy with electron backscattered diffraction observations are applied to study the evolutions of the microstructure and the texture of the alloy. Results show that the progression of pre-rolling aging decreases the incidence of micro-scaled shear bands by rolling. In addition, the rolling texture intensity decreases with the advancement of pre-rolling aging. Mechanisms responsible for this effect are discussed.