José Antônio Esmerio Mazzaferro
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Tonilson de Souza Rosendo
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Cíntia Cristiane Petry Mazzaferro
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Fabiano Dornelles Ramos
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Marco Antônio Durlo Tier
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The Friction Spot Welding - FSpW is a solid-state process that allows joining two or more metal sheets in lap configuration with no residual keyhole as occurs in the Friction Stir Welding - FSW process. The present work reports part of the efforts made at GKSS Research Centre to better understand the complex phenomena that take place during FSpW of aluminum alloys and establish the mechanical response of the resulting joints. Over the recent years the research on modeling friction based welding processes has increased considerably. Most of the works related to this subject deal with the process mechanics. On the other hand, some investigations have shown how the process variables affect the mechanical properties of the joints, but it is very difficult to find quantitative results that can be readily used for mechanical design purposes. The aim of this work is to develop an analysis procedure based on the process characteristics that allows evaluating how the resulting geometry and microstructure affect the joint mechanical behavior. For this, the results of the mechanical tests obtained on AA2024-T3 aluminum alloy were used to calibrate and validate a numerical model that was used to predict the joint failure mode. The model reproduced the specimen geometry and load conditions adopted in the lap-shear and cross-tensile tests. The joint was considered as formed by three main regions (SZ - stir zone, TMAZ - thermo mechanically affected zone and HAZ - heat affected zone) whose properties and dimensions were based in microhardness evaluation and macrographic analysis of welded specimens. It was observed a good agreement between the simulation results and experimental data. The numerical modeling of the joints allows the prediction of the joint mechanical properties, as well as to understand how a change in geometry and property of each region affects the final mechanical behavior. Based in the obtained results, the analysis procedure can be easily extended to the related friction based spot processes as Friction Stir Spot Welding - FSSW.
Preliminary study on the mechanical behavior of friction spot welds
