Fatigue of Cu-1 Pct Cd

The fatigue properties of high conductivity Cu-1 pct Cd are reported. In contrast to Cu, the fatigue strength of Cu-Cd is grain-size dependent in high cycle fatigue. Strain aging is responsible for the superior fatigue properties of Cu-Cd, and the effect of dislocation pinning is carried over to the cold work state, giving a work hardened structure which is stable in fatigue loading. A notable feature of the results is that fatigue fracture in Cu-Cd is almost entirely intergranular at long fatigue lives, in contrast to the fracture in tensile loading and in contrast to the transgranular fracture which was observed in Cu. The effect is due to segregation of Cd at the grain boundaries and to the effect of Cd on the cohesive strength of the boundary. Moderate cold work suppresses intergranular fracture. Formerly Department of Metallurgy and Engineering Materials, The University of Newcastle upon Tyne