The influence of cold deformation on electrochemical and mechanical properties of EN AW 8006 alloy

Complex requirements for quality and competition on the market place are forcing manufactures to improve existing the aluminium alloys properties and develop new ones. Such streaming has been recently expressed in the food industry where are the numerous studies dedicated to down-gauging the aluminium foil required for flexible packaging laminates, while maintaining the same barrier and rigidity properties, by optimising package design. Final performances of packaging films do not depend only on mechanical but also on corrosion properties [1]. According to the European norm EN 573-3 the Fe content in Al-Fe-Mn (EN AW 8006) alloy may vary from 1.20 to 2.00 wt. %. The article gives the results of an investigation both of mechanical and corrosion properties of the cold rolled sheets of EN AW 8006 alloy with four different levels of Fe content. The alloys cold rolling process is performed under industrial conditions. The corrosion properties of Al-Fe-Mn (EN AW 8006) were studied in a 0.5 M NaCl solution at 25oC. The methods chosen for investigation of corrosion behaviour of Al-Fe-Mn (EN AW 8006) were: (a) potentiodynamic polarization (b) cyclic voltammetry and (c) electrochemical impedance spectroscopy. By tensile tests, elastic and plastic behaviour of investigated alloys under conditions of static uniaxial tensile stress, were determined. All tests were performed on cold rolled samples in the longitudinal direction of rolling (RD) and transverse to the direction of rolling (TD). The cold rolling of aluminium alloys generates the deformed layers on surface [2]. These deformed layers have a high electrochemical reactivity which affects on corrosion resistance. Tensile strength of cold rolled samples increases and elongation decreases with increasing degree of cold deformation. Results obtained from these investigations could be useful for industrial application.