Crystal Research and Technology · 1983 · 13 citations · 13 references
Natural SciencesMaterials EngineeringMaterials ScienceMechanical Behavior Of MaterialsMetallic MaterialsSolid State PhysicsDeformation MechanismsDislocation MechanicsFracture MechanicsPlastic DeformationStrain EngineeringStress-strain BehaviorDefect StatesDeformationDislocation BehaviorDislocation DensityDislocation Density EvolutionDislocation EvolutionDislocation MechanismsElectrical Resistivity
Abstract The development of the dislocation structure in nickel single crystals push‐pull fatigued at room temperature is investigated for different deformation types using electrical resistivity measurements and results of TEM observations. The dislocation density in the bundles of the matrix is higher after changing the strain amplitude from region A to region B (CD AB ‐type) of the cyclic stress‐strain curve ( N dB ≈︁ 1.6 ≈︁ 10 15 m −2 ) than after virginal deformation in region B (VD B ‐type) especially at higher strain amplitudes ( N dB ≈︁ 0.75 ≈︁ 10 15 m −2 ). Increasing the strain amplitude within region B (CD BB ‐type) does not change N dB . The farther development of the matrix structure after reaching the v H ‐minimum during the VD B ‐type of deformation suggests the action of the „formation and dissolution”︁ – mechanism, whereas the CD BB ‐type causes the „cord”︁‐mechanism of the PSB nucleation.
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