Investigation on the microstructure evolution and strengthening behavior of rolled bonding Cu strip

The relationship and influencing mechanism among the reduction rate, the strengthening behavior and the microstructure evolution of rolled Cu strips were studied. It was found that with the increase of reduction rate, the uneven deformation behavior of the Cu strip was divided into three zones. The grain size in Zone I was refined accompanied by large-scale entangled dislocations, and a nanosheet layered texture was formed. The primary reason for the increase in the strength of the Cu strip is the combined strengthening effect of dislocation, grain boundary and texture, as well as the strengthening effect provided by some lattice friction. The grain orientation exhibited periodic transitions between <110> and <111>, <001>, which provides assistance for grain refinement and dislocation accumulation. The grains in the fracture zone of the Cu strip are elongated and refined during stretching, and flow towards the central axis of the cross-section. The fracture mechanism has shifted from cutting to a chip edge/point to a combined action of multiple mechanisms, which is also accompanied by a gradual increase in the "tearing angle". In this paper, the bonding copper strip is prepared by rolling method, which provides a new research idea and method for the preparation of bonding copper strip. The relationship and influence mechanism among microstructure, grain orientation, strength, fracture morphology and reduction rate are investigated. It was found that as the increase of reduction rate, the uneven deformation behavior of the Cu strip is divided into three zones; The grain size in Zone I has been refined into a nanosheet layered texture accompanied by large-scale entangled dislocations. The improvement of copper strip strength is caused by the combined strengthening effect of dislocations, grain boundaries, texture, and a small amount of lattice friction. The mechanism of copper strip fracture is caused by the combined or sequential action of necking to a chip edge or a point and other mechanisms.