Effect of Sn on Interface Bonding Properties of Copper-steel Bimetallic Composites

Copper-steel bimetallic composites with different Sn content were prepared by melt-casting composite method. The effect of Sn element in copper alloy on interface bonding properties of copper-steel bimetallic composites was studied. The results showed that as the Sn content increased, the copper side hardness and shear strength of the bimetallic composites were higher, along with a greater tendency to brittle fracture. The addition of Sn in copper alloy could reduce the diffusion energy barrier of Cu to Fe, the diffusion of Cu to Fe was mainly the first nearest neighbor vacancy diffusion, Cu atoms could diffuse into the grain interior or along the grain boundaries of the steel matrix. The interface of bimetallic composites included copper layer, transition zone (including copper-rich area) and steel layer, the copper-rich area was an important part of the transition zone, the copper-rich area was mainly formed by the large diffusion of Cu atoms at the interface to the side of the steel matrix, the diffusion degree of Cu and the thickness of the copper-rich area increased with the increase of Sn content in the copper alloy.