Structural and electrochemical characterization of aluminium alloys welded by friction stir welding (FSW)

• Grant number: 18/13545-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2018
• End date: December 11, 2018
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Cecilio Sadao Fugivara
• Grantee: Rafael de Camargo Bertinotti
• Host Institution: Instituto de Química (IQ). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil
• Associated research grant: 13/13235-6 - Investigation on the localized corrosion and the fatigue corrosion resistance of high strength aluminum alloys joined by friction stir welding (FSW), AP.TEM

Abstract

In this project, the different zones of the weld of the dissimilar alloys, AA2024/AA7475, obtained by Friction Stir Welding (FSW) will be characterized by local electrochemical techniques. The different zones of the weld obtained by non-consumable tool rotation (Friction Stir Welding, FSW) will be investigated. The electrochemical technique of microcell with glass capillaries of diameter between 50 and 200 micrometers will be used. This capillary delimits a very specific area in the weld region and allows a better understanding of the influence of microstructure on the corrosion processes in the weld joint: the heat-affected zone (ZTA), the thermomechanically affected zone (ZTMA) and the zone of mixture (ZM), also known as the nugget, besides the base metal (zone not affected by FSW). The surface morphology of the samples of the welded alloys will be studied by optical microscopy (OM), scanning electron with field emission cannon (FEG-SEM) and analyzed by X-ray energy dispersion spectroscopy (EDXS) and atomic force microscopy (AFM), before and after the electrochemical tests. The surface of the welded sample will be characterized by electrochemical measurements in micro regions by means of: open circuit potential as a function of time (EOC-t), polarization curves (CP) and cyclic polarization (CPC). Electrochemical noise analysis (ENA) using a cell of two similar electrodes whose sealing rings allow to expose a diameter of ~ 1mm.