Round bar ingots of hypoeutectic Cu-4 and -5 at% Zr alloys cast into copper mold were wire-drawn (WD) with drawing ratio η=5.9 and more, and the relationship between the mechanical and electrical properties and microstructures of those wires was investigated. As a result, it became obvious that the WD Cu-5 at% Zr alloy with η=8.6, which was 40 μm in diameter, reached 2234 MPa of ultimate tensile strength (UTS), 1873 MPa of 0.2% proof stress, 4.2% of total strain to failure, 126 GPa of Young's modulus and 16%IACS of electrical conductivity (
EC). As for the WD Cu-4 at% Zr alloy, it was able to be wire-drawn down to 27 μm in diameter with η=9.4.
Both UTS and Young's modulus increase linearly with the drawing ratio η. One of the reasons to indicate the high strength will be the development of nano-sized lamellar structure of α-Cu and Cu
9Zr
2 inter-metallic compound phase. Furthermore it was observed that nano-sized amorphous phase was formed within the nano-sized layer of Cu
9Zr
2 inter-metallic compound phase. Increase of the strength for heavily WD of Cu-4 and -5 at% Zr alloy wires will be due to the synergistic effect of deformation twins developed in the α-Cu phase and the formation of the nano-sized lamellar structure consisting of α-Cu and Cu
9Zr
2 inter-metallic compound phases.
The highly
EC of 16%IACS obtained for the WD Cu-5 at% Zr alloy wire can be explained by few dislocations in the high conductive α-Cu phase.
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