• Ryelandt, Sophie
• Krishnamurthy, Sanjay Channappa
• Simar, Aude

Abstract

Dissimilar metal joining has relevant applications for the reduction in mass of aerospace vehicles in particular by the replacement of screws and rivets by welds. Titanium and aluminium alloys are commonly used aerospace materials. Joining these two materials by solid state welding process greatly contributes to weight reduction along with high integrity functional joints. Joining titanium and aluminium alloys by FSW in lap configuration has been a great challenge mainly due to high tool wear, thick intermetallic compound (IMC) formation, voids and defects at weld interface. These challenges can be overcome by Friction Melt Bonding (FMB), a process inspired from FSW. FMB is an innovative process patented at UCLouvain to join dissimilar metals having large difference in melting point. This process has been widely studied for Al-Fe dissimilar welds and has been recently extended to Al-Ti dissimilar welds. This semisolid state process provides good control over the heat input, thus limiting the thick IMC formation at the Ti-Al weld interface. The spot FMB process applies uniform pressure during and after welding allowing to reduce welding defects by reducing the post weld thermal stresses. The current study evidences the process parameter influence at weld interface on the IMC formation. The strength of the FMB welds have been investigated and showed the high quality of these spot welds which is most likely due to a thin uniform nano scale Ti-Al IMC. The influence of a uniform IMC thickness on the weld strength was evaluated by subjecting the welds to subsequent heat treatments.

Topics

• impedance spectroscopy
• compound
• melt
• aluminium
• strength
• aluminium alloy
• titanium
• void
• intermetallic
• joining