Strain induced grain boundary migration effects on grain growth of an austenitic stainless steel during static and metadynamic recrystallization

Paggi, A.; Angella, Giuliano; Donnini, Riccardo

doi:10.1016/j.matchar.2015.07.003

Cited by 57 publications

(14 citation statements)

References 27 publications

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“…Since these steels do not have any notable phase transformations during cooling, the static and dynamic recrystallization processes were conventionally used to refine their grain size. [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.…”

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

106

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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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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

106

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“…If considering strain‐induced grain boundary migration as a potential mechanism for the reduction of the dislocation density in the undoped ice, grain boundary bulging (Law, ; Paggi et al, ; Prior et al, ) would be expected. This is observed for the undoped ice in Figures and .…”

Section: Discussionmentioning

confidence: 99%

The Effects of H₂SO₄ on the Mechanical Behavior and Microstructural Evolution of Polycrystalline Ice

Hammonds

Baker

2018

JGR Earth Surface

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The Earth's large continental ice sheets contain a variety of naturally occurring impurities, both soluble and insoluble. Understanding how these impurities affect the rheology, intrinsic thermodynamic properties, and fate of these ice sheets is not well understood. To investigate the effects that trace amounts of H2SO4 have on the flow and ductility of polycrystalline ice, a series of mechanical tests were conducted at −6, −10, −12.5, and −20°C using laboratory‐prepared specimens of polycrystalline ice doped with 1–15 ppm of H2SO4. Parallel tests were performed on identical but undoped specimens of polycrystalline ice. Mechanical testing included constant‐load tensile creep tests at an initial stress of 0.75 MPa and compression tests at constant displacement rates with initial strain rates ranging from 1 × 10−6 to 1 × 10−4 s−1. It was found that H2SO4‐doped specimens of ice exhibited faster creep rates in tension and significantly lower peak stresses in compression, when compared to the undoped ice. Postmortem microstructural analyses were performed using cross‐polarized light thin section imaging, X‐ray computed microtomography, Raman spectroscopy, and electron backscatter diffraction. These analyses showed that H2SO4‐doped specimens had a larger grain size at strains ≤15%, and an earlier onset of microcracking at lower strain rates than the undoped ice. Strain‐induced grain boundary migration was found to be the predominant mechanism of recrystallization in both doped and undoped specimens. Further, an aqueous phase of H2SO4 was found to exist at the grain boundaries and triple junctions of the doped ice, which is thought to have significantly contributed toward its reduced viscosity.

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“…When under high strain rate, there has no enough time for the offset, and the increase of flow stress is the macroscopic performance of the increasing deformation resistance. The calculation method for the MDRX softening fraction can be summarized [27][28][29] as:…”

Section: Mdrx Behaviors Of As-cast P91 Alloymentioning

confidence: 99%

“…The kinetic models of MDRX are usually defined by the exponent-type equations [27][28][29] as follows:…”

Section: Mdrx Behaviors Of As-cast P91 Alloymentioning

confidence: 99%

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Numerical Simulation and Experimental Research on Microstructural Evolution During Compact Hot Extrusion of Heavy Caliber Thick-Wall Pipe

Liu

Hui

et al. 2019

Chin. J. Mech. Eng.

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Compact hot extrusion (CHE) process of heavy caliber thick-wall pipe is a new material-saving production process. In order to reveal the optimum hot extrusion parameters in CHE process, the effects of the extrusion parameters on the microstructural evolution are investigated systematically. The metadynamic recrystallization (MDRX) kinetic models and grain size models of as-cast P91 steel are established for the first time according to the hot compression tests performed on the Gleeble-3500 thermal-simulation machine. Then a thermal-mechanical and micro-macro coupled hot extrusion finite element (FE) model is established and further developed in DEFORM software. The results indicated that the grain size of the extruded pipe increases with the increasing of initial temperature and extrusion speed, decreases when extrusion ratio increases. Moreover, the grain size is more sensitive to the initial temperature and the extrusion ratio. The optimum hot extrusion parameters are including that, the initial extrusion temperature of 1250 °C, the extrusion ratio of 9 and the extrusion speed of 50 mm/s. Furthermore, in order to verify the simulation precisions, hot extrusion experiment verification on the heavy caliber thick-wall pipe is carried out on the 500 MN vertical hot extrusion equipment. The load-displacement curve of the extrusion process and the grain sizes of the middle part extruded pipe are in good accuracy with the simulation results, which confirms that the hot extrusion FE models of as-cast P91 steel could estimate the hot extrusion behaviors. The proposed hot extrusion FE model can be used to guide the industrial production research of CHE process.

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Strain induced grain boundary migration effects on grain growth of an austenitic stainless steel during static and metadynamic recrystallization

Cited by 57 publications

References 27 publications

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

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

The Effects of H₂SO₄ on the Mechanical Behavior and Microstructural Evolution of Polycrystalline Ice

Numerical Simulation and Experimental Research on Microstructural Evolution During Compact Hot Extrusion of Heavy Caliber Thick-Wall Pipe

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Strain induced grain boundary migration effects on grain growth of an austenitic stainless steel during static and metadynamic recrystallization

Cited by 57 publications

References 27 publications

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

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

The Effects of H2SO4 on the Mechanical Behavior and Microstructural Evolution of Polycrystalline Ice

Numerical Simulation and Experimental Research on Microstructural Evolution During Compact Hot Extrusion of Heavy Caliber Thick-Wall Pipe

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The Effects of H₂SO₄ on the Mechanical Behavior and Microstructural Evolution of Polycrystalline Ice