Numerical analysis of surface flaking in finish rolled lead frame copper alloy

Based on the characterization of microstructure at surface flaking in Cu-Fe-P lead frame copper alloy of finish rolling, the stress and strain distributions of the interface between Cu matrix and Fe particle were analyzed using plane strain model by elastoplastic finite element method. It was shown that the stress and strain distributions in the Cu matrix and Fe particle are of significant non-homogeneity. Intense stress concentration at the interface will bring about the crack between the two phases. At the same time the micro-crack around the Fe particle before finish rolling makes it easy to develop the crack on finish rolling. So the surface flaking of lead frame copper alloy brings about. The larger Fe particles at the hot rolled plate should be avoided.