Computational investigations of the formation of intermetallic compounds in Al/Cu joints

Intermetallic compounds (IMCs) play a critical role in determining the performance of materials, particularly influencing mechanical properties and electrical conductivity. The present work elucidates the formation of IMCs in aluminum/copper (Al/Cu) joints using CALPHAD-based predictions of thermodynamic driving force and time-temperature-transformation (TTT) diagrams, benchmarked against experimental data from the literature. The analysis incorporates 90 experimental data points, encompassing various welding methods, peak temperatures, cooling rates, and chemical compositions. With collected from the literature, a good corroboration with the present simulations of thermodynamic driving forces and TTT diagrams is observed in terms of the types of IMCs formed and their formation sequence. However, the inability to predict metastable phases, attributed to incomplete thermodynamic and kinetic data, underscores the need for further research. Overall, the present work offers valuable insights into the formation of IMCs in Al/Cu joints across different welding processes and provides a systematic approach for understanding IMC formation mechanisms more broadly.