Study on the relationship between interface morphology and mechanical properties of explosive welded titanium/duplex stainless steel

This study investigated the interface morphology and mechanical properties of titanium (TP 270C)/duplex stainless steel (SUS 821L1) near the lower limit of the explosive welding window. Seven samples with different welding parameters near the lower limit of the welding window were evaluated; the interface morphology was analyzed by optical microscopy (OM), scanning electron microscopy (SEM), computed tomography (CT), and smoothed particle hydrodynamics (SPH) simulation. The jet, interface shape, and temperature at the interface were obtained by simulation, demonstrating consistent interface shapes in the experimental results and simulation results. The energy produced at the interface was proportional to the element diffusion area. To assess the differences in mechanical properties between each sample, tensile shear tests and 90 bending tests were conducted. The results revealed that the sample with an average wavelength of 270 µm and an average amplitude of 62 µm had the best tensile properties. Furthermore, the maximum tensile strength was about 503 MP. In the bending test, samples with an average wavelength of 118–270 µm and an average amplitude of 20–62 µm showed no cracks at the welding interface after bending; however, cracks appeared at both large and no-wave interfaces.