Public thesis defense Sanjay KRISHNAMURTHY - IMMC
sst |
Processing and characterization of dissimilar titanium - aluminum welds joined by Friction Melt Bonding
Friday August 21st, 2026 - 4:15pm - Auditorium BARB94 - Place Sainte-Barbe, 2 - 1348 Louvain-la-Neuve
The increasing demand for lightweight structures in the aerospace industry, driven by fuel-efficiency and sustainability requirements, has intensified interest in dissimilar material systems such as titanium - aluminum alloys. These combinations offer high specific strength and corrosion resistance but remain difficult to join using conventional fusion welding because of their dissimilar physical properties and the formation of brittle intermetallic compounds (IMCs), residual stresses, and heat-affected zone softening. Solid-state welding processes provide a promising alternative, although their effects on joint integrity and long-term performance are not yet fully understood.
This thesis advances the understanding of dissimilar Ti/Al joints produced by a modified semi-solid-state Friction Melt Bonding (FMB) process through microstructural, mechanical, residual stress, and corrosion investigations. The evolution of weld microstructure and mechanical behavior was characterized, while residual stresses were quantified using large-scale diffraction techniques and compared with Refill Friction Stir Spot Welding (RFSSW). The influence of IMC thickness was examined through post-weld heat treatment, establishing its relationship with local mechanical properties, residual stress, and joint strength. Finally, localized electrochemical techniques were employed to evaluate the galvanic corrosion behavior of FMB Ti/Al joints and the role of IMC evolution. The findings provide new insights into the relationships between processing, interfacial microstructure, residual stress, and the resulting mechanical and corrosion performance of dissimilar Ti/Al joints.
Jury members
Prof. Aude Simar (UCLouvain), Supervisor
Prof. Renaud Ronsse (UCLouvain), Chairperson
Prof. Pascal Jacques (UCLouvain), Secretary
Prof. Sylvain Dancette (INSA Lyon)
Prof. Eric Charkaluk (Ecole Polytechnique Paris)
Dr. Thaneshan Sapanathan (Curtin University, Perth)