Dislocation wall and cell structures and long-range internal stresses in deformed metal crystals

Mughrabi, H.

doi:10.1016/0001-6160(83)90007-x

Cited by 1,032 publications

(487 citation statements)

References 45 publications

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“…4b below). This confirms the relative insensitivity of the flow stress on the arrangement of the microstructure, which has been noted by many authors [20,21]. Fig.…”

Section: Junctions and Dislocations Storagesupporting

confidence: 89%

Simulation of dislocation patterns in multislip

2002

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“…4b below). This confirms the relative insensitivity of the flow stress on the arrangement of the microstructure, which has been noted by many authors [20,21]. Fig.…”

Section: Junctions and Dislocations Storagesupporting

confidence: 89%

Simulation of dislocation patterns in multislip

2002

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“…SSDs may be closely bonded dipoles or multipoles and from earlier TEM studies on fatigued oxygen free high conductivity copper samples, it can be seen that reversible cyclic deformation generated high proportions of closely bonded ladders of dislocation dipoles in persistent slip bands (PSBs) which are potentially associated with crack formation sites [33][34][35][36].…”

Section: Introductionmentioning

confidence: 99%

On the mechanistic basis of fatigue crack nucleation in Ni superalloy containing inclusions using high resolution electron backscatter diffraction

et al. 2015

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This is an authors' copy of a manuscript published in Acta Materialia Volume 97, 15 September 2015, Pages 367-379. http://dx.doi.org/10.1016/j.actamat.2015.06.035 AbstractA series of interrupted three-point bend low-cycle fatigue tests were carried out on a powder metallurgy FHG96 nickel superalloy sample containing non-metallic inclusions. High resolution electron backscatter diffraction (HR-EBSD) was used to characterize the distribution and evolution of geometrically necessary dislocation (GND) density, residual stress and total dislocation density near a non-metallic inclusion. A systematic study of room temperature cyclic deformation is presented in which slip localisation, cyclic hardening, ratcheting and stabilisation occur, through to crack formation and microstructurally-sensitive propagation. Particular focus is brought to bear at the inclusion-matrix interface. Complex inhomogeneous deformation structures were directly observed from the first few loading cycles, and these structures were found not to vary significantly with increasing number of cycles. A clear link was observed between crack nucleation site and microstructurally-sensitive growth path and the spatially-resolved sites of extreme values of residual stress and GND density.

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“…Lastly, it should be stated that a universal physical description of hardening during cyclic loading (or kinematic hardening in general) should also take into account the influence of deformationinduced dislocation microstructures on the intragranular back stress (for example, the composite scheme suggested in [24,25] when evaluating material response at large strains, or more complex strain path changes, or for numerous cycles. However, the present experiment along with the modified EPSC model strictly deals with uniaxial load reversal at small strains; where the Bauschinger effect is mostly related to the reversal of dislocation motion [21].…”

Section: Introductionmentioning

confidence: 99%

On the evolution and modelling of lattice strains during the cyclic loading of TWIP steel

et al. 2013

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The evolution of lattice strains in fully annealed Fe-24Mn-3Al-2Si-1Ni-0.06C twinning-induced plasticity (TWIP) steel is investigated via in situ neutron diffraction during cyclic (tension-compression) loading between strain limits of ±1%. The pronounced Bauschinger effect observed upon load reversal is accounted for by a combination of the intergranular residual stresses and the intragranular sources of back stress, such as dislocation pile-ups at the intersection of stacking faults. The recently modified elasto-plastic self-consistent (EPSC) model which empirically accounts for both intergranular and intragranular back stresses has been successfully used to simulate the macroscopic stress-strain response and the evolution of the lattice strains. The EPSC model captures the experimentally observed tension-compression asymmetry as it accounts for the directionality of twinning as well as Schmid factor considerations. For the strain limits used in this study, the EPSC model also predicts that the lower flow stress on reverse shear loading reported in earlier Bauschinger-type experiments on TWIP steel is a geometrical or loading path effect. AbstractThe evolution of lattice strains in fully annealed Fe-24Mn-3Al-2Si-1Ni-0.06C TWinning Induced Plasticity (TWIP) steel is investigated via in-situ neutron diffraction during cyclic (tensioncompression) loading between strain limits of ±1%. The pronounced Bauschinger effect observed upon load reversal is accounted for by a combination of the intergranular residual stresses and the intragranular sources of back stress such as dislocation pile-ups at the intersection of stacking faults.The recently modified Elasto-Plastic Self-Consistent (EPSC) model which empirically accounts for both intergranular and intragranular back stresses has been successfully used to simulate the macroscopic stress-strain response and the evolution of the lattice strains. The EPSC model captures the experimentally observed tension-compression asymmetry as it accounts for the directionality of twinning as well as Schmid factor considerations. For the strain limits used in this study, the EPSC model also predicts that the lower flow stress on reverse shear loading reported in earlier Bauschinger-type experiments on TWIP steel is a geometrical or loading path effect.

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Dislocation wall and cell structures and long-range internal stresses in deformed metal crystals

Cited by 1,032 publications

References 45 publications

Simulation of dislocation patterns in multislip

Simulation of dislocation patterns in multislip

On the mechanistic basis of fatigue crack nucleation in Ni superalloy containing inclusions using high resolution electron backscatter diffraction

On the evolution and modelling of lattice strains during the cyclic loading of TWIP steel

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