Factor Influencing Deformation Behavior of Pure Copper Castings for Electrical Parts

Factors influencing the tensile deformation behavior of pure copper castings for electrical parts were investigated. Two main types of tensile deformation behaviors were distinguished on the basis of the difference in the rupture elongation. These did not depend on the melting conditions and/or the casting design. For the deformation type with higher rupture elongation, approximately the same tensile strengths were obtained with dimpled ductile fracture surfaces. On the other hand, lower rupture elongation was always obtained for the castings fabricated without deoxidation treatment. For deformations of the lower rupture elongation type, brittle fracture surfaces with the solidification structure containing Cu-Cu2O eutectic phase were observed. Therefore, the presence or absence of the Cu-Cu2O eutectic phase was considered to be the dominant factor influencing the tensile deformation behaviors. These findings indicate that adequate deoxidation treatment is particularly important for the prevention of crack generation during deformation.