Bending Deformation and Shear Band Formation Behavior of Rolled Sheets of Cu–Ni–Co–Si Alloy

Abstract

With the miniaturization of electronic parts, the bending ability of copper alloys requires improvement. The bendability of rolled copper alloys is affected by crystallographic orientation, and it was reported that the bendability is related to the Taylor factor. When the Taylor factor of shear strain mode (M_sh) is lower than that of plane strain compression mode (M_p), shear bands might form during bending deformation. In this study, therefore, an index for the possibility of shear band formation, M_p/M_sh, was proposed, and a prediction map for shear band formation was also generated based on the crystallographic orientation analysis. Furthermore, the usefulness of the prediction map was verified by investigating the shear band formation behavior in the 90° W–shape–bent Cu–Ni–Co–Si alloy rolled sheet. The shear bands tended to form near the region with a high M_p/M_sh value. The proposed prediction map for shear band formation can potentially aid the crystallographic orientation control to enhance the bendability of copper alloys.