Fatigue of nanocrystalline copper

摘要: Nanocrystalline copper samples have been subjected to pull-pull fatigue, with an upper stress that ranged from 50 80% of the yield stress. The minimum was 10 MPa. survived several hundred thousand cycles. A moderate increase in grain size observed after cycling, on order 30%. elongated slightly course a prolonged fatigue test. amount strain is similar room temperature creep previously nanocrystalline under constant comparable maximum cyclic deformation appeared be elastic. However elastic modulus measured factor 2 (after correction for experimental errors) smaller than ordinary copper. Parallel micrometer-size extrusions were surfaces fatigued specimens. These features extended over {micro}m and are reminiscent associated PSBs seen single crystal coarse-grained metals.