Effect of the individual layer thickness and relative blanking clearance on micro-blanking for Cu/Nb multilayer composite sheets

Abstract

In this study, two types of Cu/Nb multilayer composite sheets with individual layer thicknesses of 11.11 μm and 0.35 μm, respectively, were first prepared and then tested by micro-blanking. The results show that the sheets of 0.35 μm exhibit higher ultimate tensile and shear strengths, and greater elongation, compared to those with an individual layer thickness of 11.11 μm. The sheet with an individual layer thickness of 11.11 μm achieves optimal blanking accuracy at a relative blanking clearance of 7%. Additionally, when the relative blanking clearance is 3%, it exhibits a significant proportion of smooth areas on the shear surface. Investigation of the shear surface at different ratios of punch stroke to sheet thickness (h/t) reveals that the Cu/Nb multilayer composite sheet experiences significant extrusion and bending during the micro-blanking process. Furthermore, the laminated structure exhibits remarkable continuity and deformation mobility, delaying crack formation. This study provides theoretical support for the plastic micro-blanking technology of multilayer composite.