A Review on Dissimilar Friction Stir Welding of Aluminum Alloys to Titanium Alloys

Abstract

The joining of titanium alloy with aluminum alloy is the current area of interest owing to the increasing demand to reduce weight and simultaneously achieve high strength for the aviation, automotive, and ground transportation industries in order to reduce fuel consumption. However, the dissimilar metal joining of Al–Ti poses several challenges due to the difference in metallurgical and mechanical properties. It is difficult to achieve commercially acceptable sound joints with appropriate strength using fusion welding technique due to the problem of segregation, porosity, cracks, slag inclusion, aluminum-rich Ti_xAl_y intermetallic phases, and inferior mechanical properties of the weld. To overcome all these defects of fusion welding, solid-state welding is employed, which is the coalescence of metals under the application of pressure and at a temperature lower than the melting point of the parent metals. This leads to lower heat input and the formation of less intermetallic compounds. This technique is opening doors for new research possibilities for joining dissimilar metals like titanium and aluminum. This paper focuses on presenting the progress in the field of joining Al–Ti using friction stir welding along with a detailed analysis regarding the effect of different parameters on the quality of the weld.