TIG welding of in-situproduced syntactic metal foam-filled tubes

Aluminium matrix double composites were produced via an in-situpressure infiltration method. AlSi12 alloy matrix with densely packed lightweight expanded clay aggregate particle-filled foam was produced in-situwithin AlMgSi0.5 alloy tubes. The attainable size of such double composites is limited; therefore, joining them is required to create larger parts. For the joining of these double composites, the applicability of tungsten inert gas (TIG) welding was tested. TIG welding was found to be applicable to join such composites. Metallurgically sound welded joints were produced. Nevertheless, the TIG welding of metal foam-filled tubes is very challenging and needs experienced welding personnel, and the weld bead was a bulk material, not a foam anymore.