Properties of nanocrystalline copper prepared by vacuum-warm-compaction method

Nanocrystalline Cu with average grain size of 22.8–25.3 nm was prepared by vacuum-warm-compaction method. Scanning electronic microscope, HMV-2 type microhardness tester, X-ray diffractometer, and 6157 type electrometer were used to determine the microstructure, microhardness and electrical resistivity of as-prepared nanocrystalline Cu, respectively. The results show that the microhardness of nanocrystalline Cu increases with larger pressure, longer duration of pressure or higher temperature. The highest microhardness of nanocrystalline Cu is 3.8 GPa, which is 7 times higher than that of coarse-grained copper. The electrical resistivity of as-prepared specimens is (1.2–1.4)×10−7 Ω·m at temperature 233–293 K, which is 5–6 times higher than that of the coarse-grained copper.