Interfacial Microstructure Characteristics and Mechanical Properties of Thick TU0/316L Explosively Welded Clad Plates for Nuclear Fusion Devices

Abstract:

To meet the high-performance requirements of copper/stainless steel composite materials for the “double-box lap joint structure” in nuclear fusion devices, explosive welding was employed to fabricate thick TU0/316L clad plates. The interface characteristics and their correlation with performance were investigated through microstructural characterization and mechanical testing. Results show that jet interference and wave impedance differences under explosive impact induce a periodic wavy interface (with wavelength of 789 μm). Molten mixing dominates in wave crest regions while solid-state diffusion prevails in trough regions, with deeper diffusion observed in troughs. Dynamic recrystallization occurs in TU0-side grains, whereas 316L-side grains refine to submicron scale. The interface achieves remarkable shear strength (210 MPa) and pull-off strength (230 MPa), both exceeding the ultimate strength of copper matrix. Bend testing shows no interfacial delamination, confirming superior peeling resistance. This research provides critical insights for interface design and process optimization of composite components under extreme nuclear fusion conditions.