AC-GTAW with rectangular wave unbalanced: effects on microstructure and mechanical properties of aluminum alloy

• Grant number: 10/50622-0
• Support Opportunities: Regular Research Grants
• Start date: July 01, 2010
• End date: June 30, 2012
• Field of knowledge: Engineering - Mechanical Engineering - Manufacturing Processes
• Principal Investigator: Gilberto de Magalhaes Bento Goncalves
• Grantee: Gilberto de Magalhaes Bento Goncalves
• Host Institution: Faculdade de Engenharia (FE). Universidade Estadual Paulista (UNESP). Campus de Bauru. Bauru , SP, Brazil

Abstract

The purpose this research is investigates the microstructural and mechanical effects in the reduced endurance area of the alloy AA6063, naturally aged (T5 temper) and welded by the TIG-AC process with advanced control of rectangular wave. The experimental planning includes the use of metal deposition (alloy AA4043) and variations in the fitting parameters of the wave such as: amplitude of negative current and the time of the negative polarity of the electrode, as well as in the welding speed. The microstructural characterization will be done by optical microscopy and scanning electron microscopy (SEM), including the analysis resource by dispersive energy (EDS), besides the usage of x-rays diffraction and thermal analysis (DTA/TGA). The mechanical verifications will involve the Vickers microhardness measures and the calculation of mechanical efficiency of the joints. The determination of shape coefficient of the beads, base metal dilution and estimate of the thermal efficiency of the process complete the weld evaluations. Considering direct influency of the welding procedure in the microstructural/mechanical properties of the welded joint, the expectation is that the results to be achieved allow a better application of this technique in terms of the quality requirements and weld properties, specially in the manufacturing of light structures. (AU)