Influence of directional strength-to-stiffness on the elastic–plastic transition of fcc polycrystals under uniaxial tensile loading

Wong, Su Leen; Dawson, Paul R.

doi:10.1016/j.actamat.2009.11.009

Cited by 78 publications

(31 citation statements)

References 35 publications

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“…Here grains with a high directional strength-to-stiffness ratio will yield later than grains with a low directional strength-to-stiffness ratio leading to higher lattice strains in the former grains [37]. Defining (i) the directional strength of a particular crystallographic orientations or fibre as the Taylor factor calculated in the fully developed plasticity regime, and (ii) the directional stiffness as the elastic modulus of that fibre in the elastic regime, Wong and Dawson [37] 15 demonstrated that for fcc polycrystals with high elastic anisotropy (A ≥ 2), the {200} and {111} grains have the highest and lowest directional strength-to-stiffness ratio, respectively. It follows that the {111} grains are the first to yield whereas the {200} grains yield last.…”

Section: Diffraction Elastic Constant Lattice Strains and Residual Lmentioning

confidence: 99%

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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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Section: Diffraction Elastic Constant Lattice Strains and Residual Lmentioning

confidence: 99%

“…3a). In other words, the evolution of the lattice strains in the elastic regime is dictated by the elastic anisotropy such that it follows the relative magnitude of the directional elastic modulus [37].…”

Section: The Evolution Of Lattice Strainsmentioning

confidence: 99%

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

et al. 2013

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“…Plastic deformation starts within grains whose orientation, relative to the loading axis, facilitates the easy activation of their dislocation slip systems when the critical resolved shear stress is reached; other oriented grains, which are plastically hard, will respond to the load elastically and sustain more loads leading to stress redistribution among the grains. In the case of uniaxial tensile loading, the plastically deformed grains accumulate a compressive intergranular strain, whereas the grains lying along the plastically hard orientations accommodate a tensile intergranular strain 10,13 .…”

mentioning

confidence: 99%

“…In particular, iron and its alloys are among the most anisotropic body-centred cubic metals, for instance, o1114 is the stiffest orientation that is B2.2 times as strong as the most compliant o1004 orientation 11 . As such, in response to loading, differently oriented NFA grains will sustain distinctly different elastic strains and thus generate intergranular strains to maintain compatibility with its neighbouring grains 10,12 . Plastic deformation starts within grains whose orientation, relative to the loading axis, facilitates the easy activation of their dislocation slip systems when the critical resolved shear stress is reached; other oriented grains, which are plastically hard, will respond to the load elastically and sustain more loads leading to stress redistribution among the grains.…”

mentioning

confidence: 99%

“…It is known that a single crystal exhibits elastic and plastic anisotropy, as its elastic stiffness and plastic strength depend on the crystallographic orientation. The mechanical response of a NFA grain, within a polycrystalline NFA aggregate, is dependent on its single-crystal properties, the crystallographic orientation of its lattice and those of its neighbouring grains 10 . In particular, iron and its alloys are among the most anisotropic body-centred cubic metals, for instance, o1114 is the stiffest orientation that is B2.2 times as strong as the most compliant o1004 orientation 11 .…”

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Temperature-dependent elastic anisotropy and mesoscale deformation in a nanostructured ferritic alloy

Stoica

Miller

et al. 2014

Nat Commun

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Nanostructured ferritic alloys are a new class of ultrafine-grained oxide dispersionstrengthened steels that have promising properties for service in extreme environments in future nuclear reactors. This is due to the remarkable stability of their complex microstructures containing numerous Y-Ti-O nanoclusters within grains and along grain boundaries. Although nanoclusters account primarily for the exceptional resistance to irradiation damage and high-temperature creep, little is known about the mechanical roles of the polycrystalline grains that constitute the ferritic matrix. Here we report an in situ mesoscale characterization of anisotropic responses of ultrafine ferrite grains to stresses using state-ofthe-art neutron diffraction. We show the experimental determination of single-crystal elastic constants for a 14YWT alloy, and reveal a strong temperature-dependent elastic anisotropy that leads to elastic softening and instability of the ferrite. We also demonstrate, from anisotropy-induced intergranular strains, that a deformation crossover exists from lowtemperature lattice hardening to high-temperature lattice softening in response to extensive plastic deformation.

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Crystal Plasticity and Grain‐Orientation‐Dependent hkl‐Lattice Strain in Polycrystalline SUS316

Zheng¹,

Yuan²,

Badarinarayan³

2014

TMS 2014 Supplemental Proceedings

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Influence of directional strength-to-stiffness on the elastic–plastic transition of fcc polycrystals under uniaxial tensile loading

Cited by 78 publications

References 35 publications

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

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

Temperature-dependent elastic anisotropy and mesoscale deformation in a nanostructured ferritic alloy

Crystal Plasticity and Grain‐Orientation‐Dependent hkl‐Lattice Strain in Polycrystalline SUS316

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