In situ Measurements of Irradiation-Induced Creep of Nanocrystalline Copper at Elevated Temperatures
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We have measured irradiation-induced creep on nanocrystalline copper micropillars at elevated temperatures. The micropillars, which were ≈1 µm in diameter and ≈2 µm in height, were fabricated from magnetron-sputtered nanocrystalline copper films. The micropillars were compressed during 2.0 MeV Ar+ bombardment and the deformation measured in situ by laser interferometry. The creep rate was measured over the stress range 10–120 MPa at ≈200°C. The results show linear relationships of creep rate with both applied stress and displacement rate, yielding a creep compliance of 0.07 dpa−1 GPa−1 (dpa:displacement per atom). The findings are in good agreement with the previous results obtained using a bulge test on free-standing thin film specimens.
KeywordsCreep Rate Creep Compliance Thermal Drift Bulge Test Nanocrystalline Copper
This research was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award DEFG02-05ER46217. The work was carried out, in part, in the Frederick Seitz Materials Research Laboratory Central Facilities, University of Illinois.