876 ISSN 2070-2051, Protection of Metals and Physical Chemistry of Surfaces, 2018, Vol. 54, No. 5, pp. 876–883. © Pleiades Publishing, Ltd., 2018. Relation Between Mechanical Instabilities and Corrosion Sensitivity of Aluminum Body Cans Surfaces 1 Cherif Illoul a , Nacer Zazi a, *, Ferroudja Debiane a , and Jean-Paul Chopart b a Laboratoire de Mécanique Structure et Energétique (LMSE), Département de Génie Mécanique, Université Mouloud Mammeri, B.P.17 RP, Tizi-Ouzou, 15000 Algérie b LISM EA 4695 UFR SEN, BP1039, Université de Reims Champagne Ardenne, Moulin de la Housse, Reims, Cedex, 51687 France *e-mail: zazinacer@yahoo.fr Received February 21, 2017 Abstract—In this work we investigated the mechanical and corrosion behavior of aluminum can bodies. The results obtained show homogeneous distribution of intermetallic particles. The magnesium presence, in the surface of the can bodies, causes instabilities in the tensile curves and provokes localized corrosion surround- ing the split up, fissured, sheared and non sheared intermetallic particles by dissolution of magnesium, in the Keller reactant and chloride solution, in the discontinuities of varnish in the inside of can bodies. It is also seen that the localized corrosion observed is caused by a lateral propagation mode. The heterogeneity of thickness of the can body surface, due to the deep drawing, causes an increase corrosion sensitivity of the can body surface and cancel the sheet anisotropy. The Lankford coefficient is very low in the three directions and the planar coefficient in some area takes negative values. It is also seen that all the observations showed an increase on the global strain inducing a premature beginning of diffuse necking. The zones where the diffuse necking appears are sensitive to localized corrosion. Keywords: corrosion, anisotropy, mechanical instabilities, body cans, rolling, deep drawing DOI: 10.1134/S2070205118050106 1. INTRODUCTION It is known that several parameters influence the mechanical and chemical behavior of aluminum sheets; among these parameters we can quote tem- perature, deformation and deformation rate, etc. [1]. During deformation at both high and low tempera- tures, the restoration, dynamic recovery, dynamic recrystallization, and grains lengthening can occur. Aluminum sheets have limited formability compara- tively to steel sheets; it depends on the work hardening coefficient, strain-rate sensitivity and normal anisot- ropy [2]. The latter two parameters control well the plastic instability and ductility, which can be modified by adding alloying elements and appropriate heat treatment. In addition it is demonstrated that the nor- mal anisotropy is strongly related to the texture [3]. Usually, the sheets obtained after cold-rolling are used in various industries such as manufacturing of cans. During rolling, complex microstructures develop, such as rolling texture formation and anisotropy of mechanical properties [3–5]. The formability of thin sheets of metals and alloys, and the foils used to make can bodies can be limited either by instability or by fracture depending on the heat and mechanical oper- ation prior to their use [6]. The forming limit is gener- ally defined as a locus in the homogeneous strain space necessary for the start of localized necking, however the fracture limit is defined as that required for material disjointing. In the uniaxial tension strain path, the tensile instability or diffuse necking, as char- acterized by the Considère Law, is one of the factors governing the formability of metallic sheets [6]. The effects of cold rolling consist of a work harden- ing and fragmentation of intermetallic particles during plastic processing. This leads to the orientation of the intermetallic particles, particularly, a lengthening of grains in the rolling direction, and then variable distri- bution of dislocation densities in different orientation compared to rolling direction. After cold rolling of a metal and alloy, some of the energy involved in the deformation is stored as dislocations and point defects. In the production of the cans, highly cold rolled strip is used to meet the strength requirements, thus the sheets must be anisotropic. Generally, the coeffi- cient used to characterize mechanical anisotropy of materials is the Lankford one (r). The latter is defined in uniaxial tensile tests on rectangular sheet specimens 1 The article is published in the original. PHYSICOCHEMICAL PROBLEMS OF MATERIALS PROTECTION