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Rosendo T.,Max Planck Institute for Solid State Research | Parra B.,Max Planck Institute for Solid State Research | Parra B.,Federal University of Sao Carlos | Tier M.A.D.,Max Planck Institute for Solid State Research | And 4 more authors.
Materials and Design | Year: 2011

Friction spot welding (FSpW) is a solid state welding process suitable for spot joining lightweight low melting point materials like aluminium and magnesium alloys. The process is performed by plunging a rotating three-piece tool (clamping ring, sleeve and pin) that creates a connection between sheets in overlap configuration by means of frictional heat and mechanical work. The result is a spot welded lap connection with minimal material loss and a flat surface with no keyhole. FSpW has been performed in a 1.7 mm-thick AA6181-T4 aluminium alloy using different welding parameters (rotation speed and joining time) aiming to produce high quality connections in terms of microstructure and mechanical performance. Microstructural features of the FSpW connections were analysed by optical microscopy; while mechanical performance was investigated in terms of hardness and tensile testing. Connections with shear strength close to 7 kN were obtained with high reproducibility. The results also showed that geometric features of the connection play an important role on the fracture mechanism and hence on the mechanical performance of the connections. © 2010 Elsevier Ltd. Source


Da Silva A.A.M.,Research Center En Tecnologias Of Union Lortek | Aldanondo E.,Research Center En Tecnologias Of Union Lortek | Alvarez P.,Research Center En Tecnologias Of Union Lortek | Lizarralde A.,Research Center En Tecnologias Of Union Lortek | Echeverria A.,Research Center En Tecnologias Of Union Lortek
Materials Science Forum | Year: 2010

Friction Stir Welding (FSW) is a solid-state joining process whereby no bulk melting of the base material occurs during joining. FSW avoids severe distortion and formation of as-cast coarse microstructure as well as defects arising from melting and solidification during traditional fusion welding processes. The objective of this investigation is to evaluate the effect of joining parameters on the mechanical and microstructural properties of dissimilar aluminium alloys (3 mm thick AA2024-T3 and AA7075-T6 sheets) joints produced by FSW. Microstructural features have been analysed; while mechanical performance has been investigated in terms of hardness and tensile testing. In both welding configurations the boundary between the base materials at the stir zone is clearly delineated, i.e., no material mixing is observed. © (2010) Trans Tech Publications. Source


Alvarez P.,Research Center En Tecnologias Of Union Lortek | Janeiro G.,Research Center En Tecnologias Of Union Lortek | Da Silva A.A.M.,Research Center En Tecnologias Of Union Lortek | Aldanondo E.,Research Center En Tecnologias Of Union Lortek | Echeverria A.,Research Center En Tecnologias Of Union Lortek
Science and Technology of Welding and Joining | Year: 2010

The main goal of this investigation is to study the flow pattern and mixing which take place during dissimilar friction stir welding (FSW). Aspects such as the origin of onion rings and development of welding defects are considered. An evaluation of the impact of welding parameters (rotational speed) on material mixing of AA 7075-T6 and AA 2024-T3 (3 mm thickness) dissimilar butt welds was performed. The 'stop action' technique has been employed in order to acquire a close snap shot of the flow and mixing in one of the samples which showed limited mixing but optimal mechanical performance and surface condition. A non-stable rotational flow inside the threads has been identified in this sample due to the formation of a cavity on the rear of the pin. This fact gave rise to characteristic bands in the longitudinal section but it was not enough for developing an onion ring-like mixing pattern. © 2010 Maney Publishing. Source


Da Silva A.A.M.,Research Center En Tecnologias Of Union Lortek | Aldanondo E.,Research Center En Tecnologias Of Union Lortek | Alvarez P.,Research Center En Tecnologias Of Union Lortek | Arruti E.,Research Center En Tecnologias Of Union Lortek | Echeverria A.,Research Center En Tecnologias Of Union Lortek
Science and Technology of Welding and Joining | Year: 2010

The present study investigates the effect of joining parameters on the microstructural and mechanical characteristics of dissimilar friction stir spot welding (FSSW) between AA 1050 Al and 22MnB5 hot stamped boron steel. Mechanical performance has been evaluated by shear and microhardness testing. Optical microscopy has been used to investigate the microstructure generated in the different FSSW regions. A macrostructural examination has revealed the creation of mechanical interlocking in the Al steel connections. No volumetric defects or any other imperfection has been found in all FSSW connections. Shear failure load has increased with increasing both tool rotational speed and plunge depth for all FSSW connections. Higher plunge depth has improved the mechanical interlocking between lower and upper sheet due to the formation of a larger secondary flash. Encouraging results have been obtained using coated WC-Co tools in terms of durability and joint performance. © 2010 Maney Publishing. Source

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