Microstrain and boundary misorientation evolution for recrystallized super DSS after deformation

Li, Jian-Sin; Cheng, Guan-Ju; Yen, Hung‐Wei; Yang, Yo-Lun; Chang, Horng‐Yi; Wu, Chenyu; Wang, Shing-Hoa; Yang, Jer-Ren

doi:10.1016/j.matchemphys.2020.122815

Cited by 16 publications

(9 citation statements)

References 36 publications

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“…To study the crystalline constituent evolution of this material during thermal cycling, X-ray diffraction (XRD) was conducted with the Bruker D2 Phaser at 30 kV with Cu Kα (λ = 0.154056 nm) to identify various crystalline phases. The scan rate was 0.04°/s with 0.5°/s steps from 35° to 95° (2θ) [16,26].…”

Section: Methodsmentioning

confidence: 99%

“…The samples for electron backscatter diffraction (EBSD) analysis were mechanically polished to a smooth surface through a series of grit papers with different numbers, and then further polished with 0.05 μm alumina powder before being electropolished with an electrolyte of 5% perchloric acid, To study the crystalline constituent evolution of this material during thermal cycling, X-ray diffraction (XRD) was conducted with the Bruker D2 Phaser at 30 kV with Cu K α (λ = 0.154056 nm) to identify various crystalline phases. The scan rate was 0.04 • /s with 0.5 • /s steps from 35 • to 95 • (2θ) [16,26].…”

Section: Methodsmentioning

confidence: 99%

“…Dramatic deterioration of toughness and ductility occurs from a small percentage of the sigma phase [10]. By either slow heating or cooling, the sigma phase can form at the thermo-dynamical stability from 600 • C to 1000 • C by passing through this temperature range [10,16]. Furthermore, the sigma formation induces a pronounced variation, between the ferrite and austenite, in partitioning of Cr, Mo and Ni.…”

Section: Introductionmentioning

confidence: 99%

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Large Delta T Thermal Cycling Induced Stress Accelerates Equilibrium and Transformation in Super DSS

Chen

Yen

et al. 2020

Crystals

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Based on the predicted phase diagram of super duplex stainless steel (DSS) calculated by Thermo-Calc, the maximum peak temperature 1100 °C was selected to ensure no σ phase existence. This target temperature fell into the two-phase solid solution (SS) region. A series of different thermal cycling tests were carried out with the notations of 2SS, 2SS + 3 cycles, 2SS + 7 cycles, 2SS + 13 cycles, and 2SS + 20 cycles. It was found that the trend of two-phase volume ratio variation by thermal cycling followed the predicted thermodynamic equilibrium trend. After 2SS + 7 cycles, the ratio of two-phase δ/γ tended toward the ideal 1:1. According to the electron backscatter diffraction (EBSD) analysis, the δ phase crystal orientation changed from the most frequent directions of <001> and <111> of the as-received sample to the most frequent orientation of <113> after two SS treatments. While the γ phase grain always remained at <101> orientation. The grain boundary misorientation angles of the γ grains were relatively stable, ranging from 53° to 63°, but those of the δ grains were widely distributed actively presuming the lattice rotation. The Kernel Average Misorientation (KAM) value of the local strain in face center cubic (fcc) γ grains was varied and greater than that of the body center cubic (bcc) δ phase, indicating that the former, with a large grain boundary misorientation had larger local deformation than the latter, which possesses wide random misorientation angle distribution.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Large Delta T Thermal Cycling Induced Stress Accelerates Equilibrium and Transformation in Super DSS

Chen

Yen

et al. 2020

Crystals

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“…The nature of any given grain contour depends on the misorientation of the two adjacent grains and the orientation of the boundary plane in relation to them [24]. Misorientation within grains increases with the introduction of plastic strain, which is often used as a quantitative measure to describe the degree of microstructure deformation [26]. However, the introduction of plastic strain can result in substructure formation associated with the rearrangement of dislocations [26].…”

Section: Introductionmentioning

confidence: 99%

“…Misorientation within grains increases with the introduction of plastic strain, which is often used as a quantitative measure to describe the degree of microstructure deformation [26]. However, the introduction of plastic strain can result in substructure formation associated with the rearrangement of dislocations [26]. Because of this, small misorientations are important for understanding the mechanical behavior of materials and it is important that the orientation measurements are precise [27,28]).…”

Section: Introductionmentioning

confidence: 99%

Redistribution of Grain Boundary Misorientation and Residual Stresses of Thermomechanically Simulated Welding in an Intercritically Reheated Coarse Grained Heat Affected Zone

Chavez

Estefen

Gurova

et al. 2021

Metals

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A study of the migration of the grain boundary misorientation and its relationship with the residual stresses through time immediately after the completion of a thermomechanical simulation has been carried out. After physically simulating an intercritically overheated welding heat affected zone, the variation of the misorientation of grain contours was observed with the electron backscatter diffraction (EBSD) technique and likewise the variation of the residual stresses of welding with RAYSTRESS equipment. It was observed that the misorientation of the grain contours in an ASTM DH36 steel was modified after the thermomechanical simulation, which corresponds to the measured residual stress variation along the first week of monitoring, with compressive residual stresses ranging from 195 MPa to 160 MPa. The changes in misorientation indicate that the stress relaxation phenomenon is associated with the evolution of the misorientation in the microstructure caused by the welding procedure. On the first day, there was a fraction of 4% of the kernel average misorientation (KAM) values at 1° misorientation and on the fourth day, there was a fraction of 7% of the KAM values at 1° misorientation.

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Electron Backscatter Diffraction Investigation of Heat Deformation Behavior of 2205 Duplex Stainless Steel

Song

Zhao

et al. 2021

steel research int.

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Duplex stainless steel is special because it contains two phases, namely, ferrite and austenite, which endow the duplex stainless steel the advantages of good strength, ductility, and corrosion resistance. On account of its excellent performance, it is widely used in fields as diverse as petroleum transportation, energy industry, marine industry, etc. [1][2][3] Different from that of general single-phase materials, the matrix of duplex stainless steel is always two phase in the process of processing. Ferrite and austenite show varying features in the deformation process of duplex stainless steel due to differences in the lattice structure, element content, and atomic diffusion ability between the two phases, and consequently obvious uneven deformation takes place. [4] At the same time, the high-stacking fault energy of ferrite renders the climbing and slipping of its dislocations easier, thereby leading to the occurrence of dynamic recovery (DRV). [5] On the contrary, the DRV of austenite is constrained due to its low-stacking fault energy, and dynamic recrystallization (DRX) has thus become its main softening mechanism. [3,4] In addition, the recrystallization features of the two phases differ remarkably. Ma [5] mentioned that when low-angle grain boundaries (LAGBs) continuously absorbed the dislocations caused by plastic deformation in ferrite, LAGBs rotated and increased gradually to form high-angle grain boundaries (HAGBs). The study found that the recrystallization of ferrite grains was characterized by continuous dynamic recrystallization (CDRX), whereas that of austenite showed the feature of discontinuous dynamic recrystallization (DDRX) (austenite grains nucleated in the high-energy region, mainly along grain boundaries, followed by the growth of new grains). Mozumder [6] also claimed that the recrystallization mechanisms of the ferrite and austenite phases of duplex lightweight steel were CDRX and DDRX, respectively. However, the softening mechanism of both ferrite and austenite was found to be the conversion from LAGBs to HAGBs in the study of Liu, [7] proving that the recrystallization mechanism of both phases was CDRX. The effect of ferrite on the recrystallization behavior of austenite in duplex stainless steel was investigated by Dehghan-Manshadi, [8] who believed that CDRX was the result of subgrain boundary coalescence and the softening mechanism of austenite. In fact, texture also has an important influence on the evolution of microstructure. Gao [9] found that γ-fiber has a higher Taylor factor in Ultra Purified 17% Cr Ferritic Stainless Steels, so it has higher storage energy than α-fiber, leading to preferred nucleation in grains with γ-fiber orientations during annealing. Moura [10] reported that the texture and recrystallization evolution in ferrite are

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Microstrain and boundary misorientation evolution for recrystallized super DSS after deformation

Cited by 16 publications

References 36 publications

Large Delta T Thermal Cycling Induced Stress Accelerates Equilibrium and Transformation in Super DSS

Large Delta T Thermal Cycling Induced Stress Accelerates Equilibrium and Transformation in Super DSS

Redistribution of Grain Boundary Misorientation and Residual Stresses of Thermomechanically Simulated Welding in an Intercritically Reheated Coarse Grained Heat Affected Zone

Electron Backscatter Diffraction Investigation of Heat Deformation Behavior of 2205 Duplex Stainless Steel

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