TIG and MIG welding of 6061 and 7020 aluminium alloys. Microstructural studies and mechanical properties

Summary

Series 6XXX and 7XXX aluminium alloys are considered to be of medium and high strength and are widely used in different industries, such as the aeronautical and automotive. However, their application as structural materials depends on the proper development of their joining processes. The present article describes the results obtained from evaluating the microstructure, using both optical microscopy (OM) and scanning electron microscopy (SEM), as well as the mechanical properties (hardness variations) of welds performed on the alloys with two different arc welding techniques: GTAW (TIG) and GMAW (MIG). For the latter, filler metal with Al-5Mg composition and A5.10-92 AWS denomination (AA5356) was used.