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Temperature dependence on tensile properties in metallic materials is closely related with the crystal structure: bcc materials exhibit strong dependence and then their strength is increased as lowering temperature while the elongation is dramatically decreased: fcc materials are not sensitive on the temperature and show a good ductility even at cryogenic temperature. The binary system of iron and copper shows a less mutual solubility and Fe-Cu cast forms the ferrite (bcc) and copper (fcc) dual phase structure at room temperature. In this study, tensile properties, deformation and fracture behavior of the rolled Cu-40mass%Fe alloy have been evaluated. The material which showed a good strength and elongation balance at cryogenic temperature formed a layer structure with ultra-fine grains of 1 μm in diameter. In both ferrite and copper grains, furthermore, a lot of precipitates of copper or iron was revealed. Strain was homogeneously distributed at room temperature while it tends rather to concentrate on Cu phase at low temperature. Voids formed in ferrite grains were interrupted to grow around Cu precipitates. Following reasons are considerable: (i) layer structure leads to a good strength elongation balance, (ii) ductility of soft copper grains is enhanced by Fe precipitates at low temperature, and (iii) brittle fracture of ferrite grains is suppressed by dispersed Cu precipitates.