Microstructural characterization and localized corrosion resistance study of the AA7050 aluminium alloy

• Grant number: 16/09682-5
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): September 01, 2016
• Effective date (End): August 31, 2017
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal researcher: Isolda Costa
• Grantee: Lucas Felisberto dos Reis
• Home Institution: Instituto de Pesquisas Energéticas e Nucleares (IPEN). Secretaria de Desenvolvimento Econômico (São Paulo - Estado). São Paulo , 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

Friction stir welding (FSW) was developed in the early 90s, and constituted a major breakthrough for joining Al alloys with high mechanical resistance. The procedure involves the use of a non-consumable rotating tool applied in the regions that must be joined, which are held together by applying a forging pressure. The heating caused by the tool rotation and by the plastic deformation, combined with the force applied to align the plates, causes the junction of the parts in the solid state, resulting in resistant and virtually free of defects welds. Despite of the fact that the FSW process causes neither the fusion of the material nor introduces a new material in the structure, the heating of the surface caused by the friction of the tool and by the plastic deformation results in microstructural changes, modifying the corrosion resistance of the welded area with the possible formation of galvanic couples. The aim of this project is to investigate the corrosion resistance of high strength Al alloys joined by FSW by means of electrochemical techniques with high spatial resolution and standard fatigue tests.