Influence of cyclic frequency on strain localization and cyclic deformation in fatigue

Abstract To explore the stability of typical, fatigue, dislocation structures when subjected to cycling with different frequencies, polycrystalline copper has been subjected to single- and multiblock tests under constant loading, but different frequencies of 0.5, 2 and 8 Hz. The stresses employed ranged from 68 to 110 MPa, sufficient to cover the regimes of loop patches, persistent slip bands and cells. Interesting frequency effects have been revealed for both saturation behavior and cyclic plasticity following saturation. Frequency affects the degree of strain localization and influences the resistance of certain dislocation structures to plastic deformation, for which interpretations are offered in terms of secondary dislocation behavior.

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