On the transition from a waveless to a wavy interface in explosive welding

An analysis and critique are presented of the hydrodynamic theory for wave formation in explosive welding, as proposed by Cowan et al. Based on the recent advances in the understanding of this domain, the above-mentioned study is seen to support a different mechanism, dynamic plasticity, to explain wave generation at the interface of explosively welded couples. The transition from a waveless to a wavy interface was studied by means of impact welding for three different systems (CuCu, FeFe and AlAl). It was found that this transition is dependent on the collision angle and can be expressed by means of an elastic-plastic constant, based on the static properties of the materials. The criterion developed here can be extended to determine the waveless to wavy transition velocity for any system. The necessity for the development of a mathematical model that includes shock wave physics of the phenomena to explain the pulsating pressure instability and wave generation is also emphasized.