An energy-based microstructure model to account for fatigue scatter in polycrystals

Sangid, Michael D.; Maier, Hans Jürgen; Şehitoğlu, Hüseyin

doi:10.1016/j.jmps.2010.12.014

Cited by 101 publications

(62 citation statements)

References 47 publications

(39 reference statements)

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“…An existing fatigue model, based on persistent slip bands (PSBs) [20,40,42,43], is used to identify microstructural features that are beneficial for achieving an enhanced fatigue life. A PSB of longer length is attributed to more stored strain and a higher stress concentration, therefore leading to a shorter fatigue life.…”

Section: Discussionmentioning

confidence: 99%

“…has been extended to account for the role of grain boundaries by Sangid et al [42] and implemented into a polycrystalline formulation [43]. The material of interest, RR1000, has been characterized via electron backscatter diffraction (EBSD), and the microstructural attributes have been used to create a virtual instantiation of the material.…”

Section: Design For Fatigue Enhancementmentioning

confidence: 99%

See 1 more Smart Citation

Tailoring the Properties of a Ni-Based Superalloy via Modification of the Forging Process: an ICME Approach to Fatigue Performance

Detrois

Rotella

Hardy

et al. 2017

Integr Mater Manuf Innov

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Traditionally, material design and property modifications are usually associated with compositional changes. Yet, subtle changes in the manufacturing process parameters can also have a dramatic effect on the resulting material properties. In this work, an integrated computational materials engineering (ICME) framework is adopted to tailor the fatigue performance of a Ni-based superalloy, RR1000. An existing fatigue model is used to identify microstructural features that promote enhanced fatigue life, namely a uniform, fine grain size distribution, random orientation, a distinct grain boundary distribution (specifically high twin boundary density and limited low-angle grain boundaries). A deformation mechanism map and process models for grain boundary engineering of RR1000 are used to identify the optimal thermo-mechanical processing parameters to realize these desirable microstructural features. For validation, small-scale forgings of RR1000 were produced and heat-treated to attain fine grain and coarse grain microstructures that represent the conventionally processed and grain boundary engineered (GBE) conditions, respectively. For each of the four microstructural variants of RR1000, the twin density and grain size were characterized and were in agreement with the desired microstructural attributes. In order to validate the deformation mechanisms and fatigue behavior of the material, high-resolution digital image correlation was performed to generate strain maps relative to the microstructural features. The high density of twin boundaries was confirmed to inhibit the length of slip bands, which is directly attributed to extended fatigue life. Thus, this study demonstrated the successful role of models, both process and performance, in the design and manufacture of Ni-based superalloy disk forgings.

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Section: Discussionmentioning

confidence: 99%

Section: Design For Fatigue Enhancementmentioning

confidence: 99%

Tailoring the Properties of a Ni-Based Superalloy via Modification of the Forging Process: an ICME Approach to Fatigue Performance

Detrois

Rotella

Hardy

et al. 2017

Integr Mater Manuf Innov

Self Cite

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“…It is clear that microstructuresensitive modelling methodologies are needed for the capture of the phenomena leading to FCI and, thus, HCF failure. Sangid et al [19][20][21] have developed a dislocation-driven criterion for the prediction of FCI based on the stability of an energy balance for PSB formation, including terms for dislocation-grain boundary interaction determined via atomistic simulations. Microstructure-sensitive fatigue indicator parameters (FIPs) coupled with CP modelling represents another approach.…”

Section: Introductionmentioning

confidence: 99%

Micro-scale testing and micromechanical modelling for high cycle fatigue of CoCr stent material

Sweeney

O’Brien

Dunne

et al. 2015

Journal of the Mechanical Behavior of Biomedical Materials

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This paper presents a framework of experimental testing and crystal plasticity micromechanics for high cycle fatigue (HCF) of micro-scale L605 CoCr stent material.Micro-scale specimens, representative of stent struts, are manufactured via laser micromachining and electro-polishing from biomedical grade CoCr alloy foil. Crystal plasticity models of the micro-specimens are developed using a length scale-dependent, strain-gradient constitutive model and a phenomenological (power-law) constitutive model, calibrated from monotonic and cyclic plasticity test data. Experimental microstructural characterization of the grain morphology and precipitate distributions is used as input for the polycrystalline finite element (FE) morphologies. Two microstructure-sensitive fatigue indicator parameters are applied, using local and non-local (grain-averaged) implementations, for the phenomenological and length scale-dependent models, respectively, to predict fatigue crack initiation (FCI) in the HCF experiments.

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“…These reviews highlight the need to deliver new experimental insight into deformation processes and failure in fatigue to drive modelling that can accurately capture microstructurally-sensitive effects and use geometrically faithful models. These modelling efforts have focused at a range of length and timescales, using approaches such as molecular dynamic simulations [8,9] up to the grain level using crystal plasticity finite element techniques [10][11][12][13][14][15]. This range of approaches necessitates ever increasing fidelity of experimental studies that span length and timescales, such as X-ray synchrotron [16] [17,18] and high energy neutron diffraction [19]; as well as electron microscopy [20,21] microstructurally-sensitive and physically based modelling approaches necessitate local measurements of defect content and residual stresses to improve the prediction of fatigue crack nucleation and short crack growth.…”

Section: Introductionmentioning

confidence: 99%

“…Modelling efforts using molecular dynamics [8] and crystal plasticity finite element [13] techniques lead to the conclusion that fatigue crack formation criteria should be closely linked to stored energy which, for materials that deform plastically, is related to stored dislocation density.…”

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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An energy-based microstructure model to account for fatigue scatter in polycrystals

Cited by 101 publications

References 47 publications

Tailoring the Properties of a Ni-Based Superalloy via Modification of the Forging Process: an ICME Approach to Fatigue Performance

Tailoring the Properties of a Ni-Based Superalloy via Modification of the Forging Process: an ICME Approach to Fatigue Performance

Micro-scale testing and micromechanical modelling for high cycle fatigue of CoCr stent material

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

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