Studies on thermal stability, mechanical and electrical properties of nano crystalline Cu99.5Zr0.5 alloy

Cryogenic high energy ball milling was used to synthesize nanocrystalline Cu and Cu99.5Zr0.5 alloys by mechanical alloying and consolidation by hot pressing at 550 °C temperature. The grain size stability of nanocrystalline Cu is improved by the Zr addition. Microstructural characterization using X-ray diffraction and transmission electron microscopy provided evidence for the formation of a Cu–Zr alloy solid solution with nanocrystalline size after hot pressing. The alloy exhibited a higher hardness (3.31 GPa), and shear strength (550 MPa) than nano-crystalline pure Cu however, the electrical resistivity is increased in the alloy.

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► 0.5 at.% of Zr addition is an excellent candidate for stabilizing nanocrystalline Cu.
► The Cu99.5Zr0.5 alloy shows better mechanical properties than nanocrystalline Cu after hot-pressing at 550 °C.
► However, electrical resistivity is higher than nanocrystalline Cu.