Parameter-determined interface morphologies and properties of explosively-welded Cu–Ni–Si–Cr alloy composites

Six Cu–Ni–Si–Cr alloy composites are prepared by explosive welding with the designed parameters. Wavy interface containing the melted pockets and shrinkage cracks is always observed, refining the grains to just several micrometers with the localized deformation. Resultantly, the interface regions show higher hardness and yield strength than elsewhere, reaching HV 190 and over 400 MPa, respectively, but their plasticity is less than half that of the base-plate parts. Theoretical analysis successfully relates the area of the total disrupted regions including the interfacial molten and wavy zones in the composites linearly to the flyer-plate thickness (hf) and collision angle (β) as (hfsin2β2)2. For the composite fabricated at an impact velocity and angle of 310 m/s and 8.0°, respectively, strengthening mechanism calculation for its interface part reveals that grain boundary, dislocation and solid solution hardening are most effective and contribute 68 MPa, 370 MPa and 39 MPa individually, making the dislocation hardening dominant for the enhanced strength.