Controlling strength and ductility: Dislocation-based model of necking instability and its verification for ultrafine grain 316L steel

Vinogradov, Alexei; Yasnikov, I. S.; Matsuyama, Hirofumi; Uchida, Makoto; Kaneko, Yoshihisa; Estrin, Yuri

doi:10.1016/j.actamat.2016.01.005

Cited by 68 publications

(28 citation statements)

References 46 publications

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“…A dynamic balance between dislocation generation and annihilation determines the work hardening rate, while the uniform strain during tensile deformation is primarily controlled by the rate of dynamic recovery [31]. In this study, the high Cu solute contents can retard the annihilation of dislocations by pinning the migration of mobile dislocations and accordingly, the ECAP processed material can reach a higher supersaturating density of dislocations, resulting in a high work hardening rate, thus improving the uniform elongation.…”

Section: Tensile Propertiesmentioning

confidence: 88%

The deformation and work hardening behaviour of a SPD processed Al-5Cu alloy

Jia

Bjørge

Marthinsen

et al. 2017

Journal of Alloys and Compounds

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An Al-5 wt.% Cu alloy supersaturated with Cu in solid solution was subjected to equal channel angular pressing (ECAP). The microstructural evolution was systematically investigated by backscattered electron (BSE) imaging, electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). It is revealed that a bimodal grain structure composed of coarse micron-sized grains and submicron-sized grains was developed after four passes of ECAP. Tensile testing showed that a high ultimate tensile strength of ~500 MPa, a high elongation to failure of ~28% and a uniform elongation of ~5% were achieved simultaneously. The deformation behaviour and the grain structure evolution during ECAP, the strengthening mechanisms of the as-deformed material, and especially, the role played by a high content of Cu have been discussed.

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Section: Tensile Propertiesmentioning

confidence: 88%

The deformation and work hardening behaviour of a SPD processed Al-5Cu alloy

Jia

Bjørge

Marthinsen

et al. 2017

Journal of Alloys and Compounds

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“…[3,7] However, these processes are not very effective compared with severe plastic deformation techniques. [8] As a result, a heuristic thermomechanical treatment has been developed, which is based on the formation and subsequent reversion of strain-induced martensite (SIM) in metastable ASSs. [9][10][11][12][13][14][15] Austenite stability (chemical composition and the initial grain size) and cold working variables (temperature, strain, strain rate, and stress state) play critical roles on the formation of martensite and its amount.…”

Section: Introductionmentioning

confidence: 99%

Microstructural Evolutions During Annealing of Plastically Deformed AISI 304 Austenitic Stainless Steel: Martensite Reversion, Grain Refinement, Recrystallization, and Grain Growth

Naghizadeh

Mirzadeh

2016

Metall Mater Trans A

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MEYSAM NAGHIZADEH and HAMED MIRZADEHMicrostructural evolutions during annealing of a plastically deformed AISI 304 stainless steel were investigated. Three distinct stages were identified for the reversion of strain-induced martensite to austenite, which were followed by the recrystallization of the retained austenite phase and overall grain growth. It was shown that the primary recrystallization of the retained austenite postpones the formation of an equiaxed microstructure, which coincides with the coarsening of the very fine reversed grains. The latter can effectively impair the usefulness of this thermomechanical treatment for grain refinement at both high and low annealing temperatures. The final grain growth stage, however, was found to be significant at high annealing temperatures, which makes it difficult to control the reversion annealing process for enhancement of mechanical properties. Conclusively, this work unravels the important microstructural evolution stages during reversion annealing and can shed light on the requirements and limitations of this efficient grain refining approach.

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“…Accelerated recovery and an associated decrease in dislocation density as main creep damage mechanism were reported from experimental results [5,24] and computation [25]. The nucleation of cavities followed by growth and interlinkage is believed to play an important role in creep failure of metals [9,10].…”

Section: Introductionmentioning

confidence: 99%

Basic modelling of tertiary creep of copper

Sui

Sandström

2018

J Mater Sci

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Mechanisms that are associated with acceleration of the creep rate in the tertiary stage such as microstructure degradation, cavitation, necking instability and recovery have been known for a long time. Numerous empirical models for tertiary creep exist in the literature, not least to describe the development of creep damage, which is vital for understanding creep rupture. Unfortunately, these models almost invariably involve parameters that are not accurately known and have to be fitted to experimental data. Basic models that take all the relevant mechanisms into account which makes them predictive have been missing. Only recently, quantitative basic models have been developed for the recovery of the dislocation structure during tertiary creep and for the formation and growth of creep cavities. These models are employed in the present paper to compute the creep strain versus time curves for copper including tertiary creep without the use of any adjustable parameters. A satisfactory representation of observed tertiary creep has been achieved. In addition, the role of necking is analysed with both uniaxial and multiaxial methods.

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Controlling strength and ductility: Dislocation-based model of necking instability and its verification for ultrafine grain 316L steel

Cited by 68 publications

References 46 publications

The deformation and work hardening behaviour of a SPD processed Al-5Cu alloy

The deformation and work hardening behaviour of a SPD processed Al-5Cu alloy

Microstructural Evolutions During Annealing of Plastically Deformed AISI 304 Austenitic Stainless Steel: Martensite Reversion, Grain Refinement, Recrystallization, and Grain Growth

Basic modelling of tertiary creep of copper

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