Production of aluminium based composites reinforced with embedded NiTi by friction stir welding

Mendes, Luís Gonçalves

http://hdl.handle.net/10362/8764

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Autores

Mendes, Luís Gonçalves

Orientador(es)

Miranda, Rosa

Santos, Telmo

Resumo(s)

Aluminium alloys have been widely used in composite materials in order to promote an enhancement in its properties while reducing weight. As in the production of new composites with a significant difference in mechanical and thermo-physical properties fusion welding processes enhances the formation of undesired intermetallics. Those limitations have driven research on solid state technologies, such as Friction Stir Welding (FSW), for joining dissimilar materials. This study aimed to develop composites in AA 1XXX series aluminium alloys with NiTi by FSW. Different reinforcing material shapes were investigated, analyzed the interfaces and the resulting material flow. The final product was mechanically characterized. It was observed an increase of 70 % of ultimate tensile strength, compared to Al base material and yielding between the two dissimilar materials was greater than the Al lap joint yield stress. The final composite depicted a good electrical conductivity, reducing less than 3 % IACS of the Al base material. Thus, a composite with a strong mechanical bonding was produced, maintaining the original functional properties of the reinforcement NiTi alloy, and the electrical properties of the Aluminium.