In recent years, the size and weight of products dealt with in industry have been getting smaller and smaller and micro-bonding and micro-processing technology has become important. Underwater explosive welding can be an alternative bonding method for very thin materials, with a low formability, and which are difficult to bond together by traditional explosive welding methods. In this study, NiTi shape memory alloy and copper foil were welded in this new method. The welding process was simulated using the commercially available package LS-DYNA. The numerical simulation gave the deformations of the flyer and the base plate, and the pressure distribution during the welding process. Microstructure and fracture mechanism of the welded metals were evaluated. The bond interface of the welded metals showed a wavy morphology and the fracture mechanism of the composite laminate showed a predominantly quasi-cleavage with cleavage modes. (C) Koninklijke Brill NV, Leiden, 2012