Modeling analysis of interface waves in titanium-aluminum explosive welding using a thermoplastic coupled SPH-FEM method

The interfacial microstructure and local elemental redistribution directly affect the bonding strength and impact resistance of lightweight TC4/Al6061 clad armor plates fabricated by explosive welding. To reveal the formation mechanism of the interface waves and evaluate the potential reaction region in TC4/Al6061 explosive welding, a thermoplastic coupled SPH-FEM model was implemented in the OpenRadioss through secondary development and was employed to simulate the interface-wave formation and thermal response during TC4/Al6061 explosive welding. Subsequently, corresponding explosive welding experiments were conducted, and the bonded interface was characterized by microstructural observation and energy-dispersive spectroscopy. The temperature field of the bonded interface and the formation process of the interface waves were reproduced by the thermoplastic coupled SPH-FEM method. The results indicate that the simulated potential reaction region is localized within a narrow high-temperature zone of the bonded interface and is spatially consistent with the measured elemental transition zone. Furthermore, the interface-wave dimensions obtained from the simulations are consistent with the metallographically measured dimensions, with a relative error of 5%. As a robust numerical algorithm, the thermoplastic-coupled SPH-FEM method can accurately simulate the formation process of interface waves in TC4/Al6061explosive welding and estimate the potential formation region of the Ti-Al intermetallic compounds layer at the bonded interface.