Discontinuous Recrystallization Research Articles

Microstructure and strengthening mechanism of TIG welded joint of AZ31 alloy based on FSP technique

Magnesium alloys, renowned for their outstanding properties, present promising applications within the realm of advanced manufacturing. Addressing the challenges of coarse grains and inferior properties in the fusion welding of magnesium alloys, a novel strengthening approach for fusion-welded joints is proposed in this study. This method employs fine, uniform, and dense grains as the matrix, with particle-reinforced structures serving as the strengthening backbone. By utilizing powder feeding in conjunction with fusion welding and friction stir processing, ideal microstructures were successfully fabricated, and the mechanisms influencing grain morphology and joint properties were explored. Following the strengthening treatment, the grain size of the magnesium alloy molten weld was reduced from 193.5 μm to 15.9 μm, resulting in a grain refinement efficacy of 91.8 %. Concurrently, the tensile strength was augmented by 70.2 MPa, and the elongation experienced a 136 % enhancement. The grain morphology, eutectic phase structure, texture strength, precipitated phase type and dislocation distribution at each processing stage of the welded joint were observed. Research shows that nano-enhanced particles adhere to the eutectic structure of grain boundaries, effectively inhibiting the diffusion of solute elements and significantly reducing the dendrite growth rate. It is the main mechanism by which reinforced particles lead to grain refinement. Discontinuous recrystallization during FSP treatment leads to grain refinement, work hardening and enhanced pinning of particles at grain boundaries, which are the main reasons for the strength improvement.

Thermal restoration kinetics and microstructural evolution of an Mg-RE alloy during annealing by quasi-in-situ observation

Quasi-in-situ electron backscatter diffraction method is applied to properly investigate thermal restoration kinetics and microstructural evolution of a commercial WE54 alloy after 10 % engineering pre-strain and post-annealing at 500 °C for 10, 35, and 70 min. Results show a reduction in the average grain orientation spread can effectively evaluate the restoration kinetics compared to other characteristics like average grain size or average misorientation angle. For microstructural evolution, nucleation behavior and abnormal grain growth of recrystallization nuclei as well as evolution of deformation twin have been investigated in detail. Low-angle grain boundary network due to the recovery effect provides recrystallization nuclei in the early stage of annealing, after which both continuous and discontinuous recrystallization nuclei are observed near deformation twin boundaries and original high-angle grain boundaries. Afterwards, grains with a tilting angle of 30° from the transverse direction grow abnormally, replacing the deformed grains, deformation twins, and part of some recrystallized grains. In addition, some twins can grow into the adjacent grains while de-twinning also occurs depending on twin orientations during thermal restoration.

Static recrystallization behavior and strengthening mechanism of a single-phase Cu–18Ni–17Zn alloy

The microstructural evolution and recrystallization behavior of a single-phase Cu–18Ni–17Zn alloy during annealing has been investigated. The strengthening effects of the solute atom concentration, grain size, and recrystallized volume fraction have also been studied. The results have shown that the difference in yield strengths for the fully recrystallized samples mainly depended on the grain boundary strengthening effect. This is attributed to a constant (∼41 MPa) solid-solution strengthening contribution in the completely recrystallized Cu–18Ni–17Zn alloy. When compared with pure copper, this alloy exhibited a high Hall-Petch constant (∼0.36 MPa m1/2), which is due to the higher grain boundary interface energy. A discontinuous recrystallization occurred in the alloy in the temperature range 400 °C–500 °C. Furthermore, the yield strength was linearly correlated to the recrystallized volume fraction in the partial recrystallized samples. Moreover, the addition of Ni and Zn increased the recrystallization temperature and slowed the recrystallization kinetics. The activation energy for the recrystallization was estimated as 92.6 ± 5.1 kJ/mol in the cold-rolled Cu–Ni–Zn alloy, which indicates that the grain boundary migration during recrystallization was mainly controlled by diffusion along the grain boundaries. In addition, the recrystallized grains preferentially nucleated at shear bands with high strain energies in the Cu–Ni–Zn alloy during annealing. As the regions of shear banding were completely consumed, new recrystallized nuclei formed at the grain corners. The limited number of nucleation sites resulted in a low Avrami exponent value that ranged from 0.41 to 0.61.

In-Situ EBSD Study of Phase Transformation in Additively Manufactured Titanium Alloy

The phase transition and grain refinement features of a Ti-6Al-4V alloy are investigated in this study using in-situ high- temperature Electron Backscatter Diffraction (EBSD). The objective of the experiment was to detect the phase transition from Body-Centered Cubic (BCC) to Face-Centered Cubic (FCC) systems at temperatures ranging from 770 to 900 degrees Celsius. Grain refinement techniques such as recrystallization twin generation, Kernel Average Misorientation (KAM), and low-angle grain boundary creation were the focus of this study. According to our research, phase transformation maps taken at 770°C, 810°C, 840°C, and 900°C reveal that a discontinuous recrystallization process was responsible for the transformation and recrystallization. The results of this investigation provide support to the theory that high-temperature treatments may enhance the microstructure of additively made Ti-6Al-4V alloys. At temperatures of 900 °C, the grain structure was evenly polished, and an almost complete phase shift to a face-centered cubic (FCC) shape was observed.

A systematic study on thermo-mechanical behavior, processing maps and recrystallization mechanism of Incoloy825 superalloy during hot compression

This study conducted isothermal hot compression experiments on Incoloy825 superalloy, spanning temperatures from 1000 to 1150 °C, strain rates from 0.01 to 10 s−1, and a true strain of 0.69. Employing Electron Backscatter Diffraction and Transmission Electron Microscopy for characterization, the research systematically explored the alloy's thermal-mechanical behavior, hot processing maps, microstructural evolution, and dynamic recrystallization (DRX) mechanisms during hot deformation. True stress-strain curves were obtained for various deformation conditions, corrected, and used to establish a highly precise constitutive model. A hot processing map was constructed using the Dislocation Migration Model theory. Through comparative analysis with microstructures, it identified the optimal hot processing parameters for Incoloy825 superalloy within the range of 1110–1150 °C, 0.01–0.3 s−1, and 3.3–10 s−1. Microstructural analysis revealed a positive correlation between temperature and the extent of DRX in the alloy, with an acceleration in the transformation from Low-Angle Grain Boundaries (LAGB) to High-Angle Grain Boundaries (HAGB). The temperature of 1100 °C served as a critical point for the influence of strain rate on the microstructure. Below this temperature, DRX and HAGB proportions initially decreased and then increased with higher strain rates, while at higher temperatures, they directly correlated with strain rates. The study also investigated DRX mechanisms, determining Dynamic Discontinuous Recrystallization (DDRX) as the primary mechanism, more active at higher temperatures and strain rates. Continuous Dynamic Recrystallization (CDRX) served as a supplementary mechanism, especially in high-temperature and low-strain-rate deformation. Twins acted as favorable nucleation sites for DRX, facilitating both DDRX and Twin-DRX (TDRX) processes in Incoloy825 superalloy.

Investigations on the microstructural evolution and mechanical properties of Al-Cu-Al tri-metal strips fabricated through roll bonding and heat-treatment processes

ABSTRACT Aluminum alloys have recently become increasingly popular in the automobile industry. In this work, roll bonding technology was developed to fabricate the composite sandwich structure (tri-metal strip) of AA5083 alloy with a Cu interlayer. The apposite surface treatment, intermittent annealing, and thickness reduction resulted in desirable metallurgical characteristics and mechanical properties. The micrographs revealed crack-free flat joints, indicating excellent bonding between the layers of AA5083 and Cu. Also, the presence of sub-grains and dislocations between boundaries suggested a continuous and discontinuous recrystallization process. The phase composition analysis confirmed the formation of intermetallic compounds at the interface. The fabricated composite exhibited a microhardness of 124.2 HV and a tensile strength of 566.66 MPa.

Subtle microstructural changes during prolonged annealing of ODS-Eurofer steel

Reduced-activation ferritic-martensitic oxide-dispersion-strengthened (RAFM-ODS) Eurofer steel is a potential candidate material for structural applications in fusion reactors. Microstructural stability during long-term exposure at high temperatures is a key issue. Depending on the amount of prior cold-rolling strain and service temperature, important solid-state restoration reactions occur such as recovery, recrystallization and particle coarsening. ODS-Eurofer steel was cold rolled up to 80% reduction in thickness and annealed at 800 °C for durations up to 4320 h. Changes in microstructure were tracked by X-ray diffraction measurements using synchrotron radiation in post-mortem specimens to estimate dislocation character and density. The volume fraction of recrystallized grains was estimated using grain orientation spread (GOS) maps from electron backscatter diffraction (EBSD). Most of the softening occur in the first hour of annealing and it seems to be closely related to discontinuous recrystallization where a few special grain boundaries overcome Zener-Smith pinning effects caused by fine and stable Y2O3-based particles. M23C6 carbides undergo coarsening upon annealing and, as a result, extended recovery is the predominant softening mechanism as annealing proceeds, although only about 15% softening is noticed after annealing for 4320 h. Using thermodynamic and kinetic calculations, the results were extrapolated to the predicted service temperature of 650 °C. The results suggest that the remarkable microstructural stability of ODS-Eurofer would withstand almost 180 years at high service temperatures without major loss of the mechanical properties of the materials.

Stability and deviations from the cube texture during rolling and annealing of Ni foil

Formation of the {100}<001> cube texture component has been reported extensively in many heavily deformed face-centered cubic (FCC) metals and alloys after annealing. The present study shows how to avoid the formation of strong cube texture on the surface of high-temperature annealed Ni foils subjected to large rolling reductions and also retain the high intensity of twin boundaries. The evolution of the surface texture of rolled and annealed foils are discussed in comparison to conventional rolling, shear, and recrystallization texture components. The stability of the cube and ND-rotated cube components in rolled foils are elaborated. In spite of discontinuous recrystallization mechanisms, a high fraction of rolling texture components is retained after annealing. Suppression of the cube component after annealing has been attributed to the constricted-annealing process and possible activation of low-energy twin boundaries. Annealing twins were found to form during the recrystallization process via a growth fault mechanism.

Oxidation-induced recrystallization and damage mechanism of a Ni-based single-crystal superalloy during creep

The creep tests for Ni-based single-crystal superalloy are carried out under 980 °C, and the microstructure at the crack tip is characterized at micro- and nano- scales. Numerous γ’ phase dissolution, nucleation and growth of fine grains are observed near the crack. In addition, γ’ phase did not effectively hinder the nucleation and growth of recrystallization grains at the oxidation-affected zone. Instead, recrystallization promoted the degradation of the γ’ phase to dissolve along the recrystallized grain boundaries. Combining the sub-grain boundary growth model proposed by Winning et al. and the discontinuous recrystallization model suggested by D.G. Cram, a recrystallization and oxidative damage model for Ni-based single-crystal superalloy is proposed. • Local polycrystallization or recrystallization will greatly damage the high-temperature properties of the alloy. From the point of view of Ni-based single-crystal superalloy design, polycrystallization during medium-high temperature creep is very rare and should be strictly avoided. • Many researches have paid attention to the recrystallization of polycrystalline Ni-based superalloys. However, there is no report about the appearance of polycrystallization region in Ni-based single crystal superalloys during creep. Additionally, systematic research and explanation on the mechanism of discontinuous recrystallization of Ni-based SC superalloy are also very lacking. • In this paper, it is found for the first time that in the process of medium-high temperature (980 °C) creep under low stress level, polycrystallization region and a large amount of γ’ phase dissolve appeared at the crack tip, which leads to a sharp decline in the properties of the alloy. Researchers believed that the γ’ phase is the main factor that hinder the recrystallization of Ni-based single-crystal alloy. Nevertheless, this paper propose that the local strain and depletion of solute atoms makes the sub-grain boundaries tend to become the nucleation of recrystallization.

Recovery, recrystallization and precipitation behavior in an ATF FeCrAl alloy during annealing treatment

Microstructure evolution of FeCrAl alloy during annealing is critical to the properties and fabrication of the accident-tolerant fuel cladding tubes. In this study, the recovery/recrystallization behavior and the accompanying precipitation process in a warm-rolled Fe-13Cr-4Al-1.85Mo-0.85Nb alloy subjected to annealing at 500–1100 °C were systematically studied. Three distinctly different stages during the annealing treatment were identified: recovery, extended recovery and discontinuous recrystallization. The alloy was always in the recovery state when annealed at 500–600 °C until 6480 min, and it maintained the extended recovery state at 700 °C until 5040 min. During annealing at 800–1100 °C, it successively experienced the recovery, extended recovery and discontinuous recrystallization stages. The simultaneously formed Laves phase had a stronger pinning effect to dislocations rearrangement and subgrain boundaries migration, thus delaying the recrystallization process. When the alloy was annealed at higher temperatures, the precipitates notably coarsened and even re-dissolved into the matrix. The mechanical properties of the alloy were dependent by the precipitation strengthening and recovery or recrystallization softening. The recovery microstructure provided the best tensile strength with good plasticity, and the discontinuous recrystallization microstructure provided the optimal plasticity with a notably decreased strength. The discontinuous recrystallized alloy exhibited the least degradation of mechanical properties at service temperature. The recrystallization and precipitation kinetics were also studied in detail, and the relationship between the microstructure and properties was discussed.

Microstructures and mechanical properties of a CoCrFeNiMn high-entropy alloy obtained by 223 K cryorolling and subsequent annealing

CoCrFeNiMn high-entropy alloy (HEA) sheets were processed by 223 K cryorolling, cold rolling, and subsequent annealing. The mechanical properties and microstructures of rolled and annealed HEA sheets were analyzed. The cryorolled samples exhibited increased strength and ductility compared to cold-rolled samples. After cryorolling, the yield stress of the HEA increased to 1259 MPa from 161 MPa in its as-cast state, and it is 1082 MPa for cold-rolled HEA. After annealing, cryorolled samples also retained greater strength and ductility compared to cold-rolled samples. The secondary twins, nano twins with increased proportions and smaller spacing contributed to the increased strength and ductility of cryorolled HEA. Continuous recrystallization occurred in cryorolled samples via subgrain migration during subsequent annealing, whereas discontinuous recrystallization occurred in cold-rolled samples via grain boundary arched nucleation. Finally, we focused on the discussion of the microstructure evolution mechanism during annealing.

Microstructure evolution, texture development, and mechanical properties of hot-rolled 5052 aluminum alloy followed by annealing

Aluminum alloys, especially the 5000 series, have drawn the attention of the transportation industry due to their lightweight and consequently reduced fuel consumption. In this regard, one of the major problems of this alloy is its low strength and ductility that can be solved using rolling and post-annealing. Accordingly, the present study concentrates on this issue. Microstructural images showed that the rolling process develops a lot of tangled and trapped dislocations in the sample, which gradually lead to the formation of dislocation bundles and networks. Subsequent annealing can produce a more homogeneous structure with clear grain boundaries and low dislocation density in the inner region of the grains. However, grain refinement efficiency through rolling is retained even after annealing. Initial and rolled Al5052 with the maximum intensity of 2.87 and 6.33 possess the lowest and highest overall texture. Also, post-annealing decreases the texture intensity to 6.33 and 4.87 at 150 and 200 °C, respectively. In this context, deformation texture components strengthen considerably after the rolling process due to the formation of shear bands, and they slightly weaken during heat treatment. Although the initial annealing of the as-received material does not cause discontinuous recrystallization during rolling, it may facilitate the material recovery before rolling. Post-annealing was found to decrease the improved effect of strength by rolling and increase the negative influence of ductility due to the inhibition of dislocation strengthening. The results showed that both dislocation density and the precipitation of Mg atoms are influential for electrical resistivity.

Microstructure and Crystallographic Texture Evolution during Isothermal Annealing of Cold-Rolled Fe-6.8Al Low-Density Steel

In the present work, the microstructural evolution in heavily cold-rolled and annealed Fe-6.8Al low-density steel has been studied. The evolution of texture with a strong component \(\left\{ {001} \right\}\langle 110\rangle\) has been observed upon cold rolling. After recrystallisation, the formation of texture with \(\left\{ {111} \right\}110\) component and other γ fiber orientations with weak intensities have been noticed. The mechanism of recrystallisation is discontinuous recrystallisation. The evolution of texture with near \(\left( {04\overline{1}} \right)\left[ {501} \right]\) and \(\left( {31\overline{8}} \right)\left[ {\overline{4}\overline{3}\overline{2}} \right]\) components in the partially recrystallised microstructures have been observed. The recrystallised grains nucleate close to the boundaries of the deformed grains and are bounded by high angle grain boundaries which are easily identified from the image quality maps. Analysis of grain size of the annealed samples shows that the presence of Al reduces the grain boundary mobility by solute drag.

An investigation of cryogenic-aging process attemptted to alleviate mechanical anisotropy of 7055 thick plate

Considering the application of cryogenic treatment in aerospace manufacturing field, the hot rolled 7055 Al–Zn–Mg–Cu alloy thick plate was selected in order to solve its mechanical anisotropy. Several cryogenic-aging processes were applied by introducing deep cryogenic treatment, pre-deformation and natural aging as pre-treatments and two-stage artificial aging as final treatment. An optimized artificial aging parameter in this paper is 110 °C/6 h + 130 °C/16 h, for a best preformance (Rm-max = 668 Mpa, Rp0.2-max = 635 Mpa, A25mm-max = 8.52%) in transverse direction. Nearly all the samples pre-treated by various cryogenic processes obtain stable plastic deformation capacity. Generally, there exist geometric recrystallization, continuous recrystallizaion and discontinuous recrystallization, to some extent in different period of cryogenic-aging process. The final morphology is the result of a mutual compromise between pinning effect originated from cryogenic or natural aging precipitates and recrystallization driving force originating from the energy stored in cryogenic or pre-tensile deformed microstructure. For the thick plate of hot-rolled AA7055, the pair of original rolling Brass components can be enhanced by cryogenic treatment or compressive deformation along transverse direction. But the final texture and the morphology of Σ3n GBs are affected mainly in artificial stage due to various abilities of recovery and discontinuous recrystallization in different directions. Tensile plastic deformation and cycled cryogenic treatment can destroy the Brass components, together with continuous straight geometrically necessary boundaries, more effectively. Since precipitation is probablely accelerated through pre-treatments, a modification of artificial aging time has promising prospect to achieve more excellent mechanical performance.

High Strain Rate Deformation Behavior and Recrystallization of Alloy 718

To study the deformation behavior and recrystallization of alloy 718 in annealed and aged state, compression tests were performed using Split-Hopkinson pressure bar (SHPB) at high strain rates (1000 to 4000 s−1), for temperatures between 20 ^circ C and 1100 ^circ C (293 K to 1373 K). Optical microscope (OM) and electron back-scatter diffraction (EBSD) technique were employed to characterize the microstructural evolution of the alloy. The stress–strain curves show that the flow stress level decreases with increasing temperature and decreasing strain rate. In addition, up to 1000 ^circ C, the aged material presents higher strength and is more resistant to deformation than the annealed one, with a yield strength around 400 MPa higher. For both states, dynamic and meta-dynamic recrystallization occurred when the material is deformed at 1000 ^circ C and 1100 ^circ C, leading to a refinement of the microstructure. As necklace structures were identified, discontinuous recrystallization is considered to be the main recrystallization mechanism. The recrystallization kinetics is faster for higher temperatures, as the fraction of recrystallized grains is higher and the average recrystallized grain size is larger after deformation at 1100 ^circ C than after deformation at 1000 ^circ C.

The evolution of abnormally coarse grain structures in beta-annealed Ti-6Al%-4V% rolled plates, observed by in-situ investigation

The factors controlling the evolution of abnormally coarse grain (ACG) structures during standard β annealing of titanium-6Al%-4V% (Ti64) hot-rolled plates, have been investigated in more detail than previously, using both ex-situ through-thickness large area, and in-situ EBSD micro-texture observation. Starting with a typical, through thickness, α+β deformation texture distribution that gives rise to ACGs at the plate mid-section, each stage of the annealing process has been sequentially characterised and phenomenologically linked to the spatial texture evolution that occurs during transient heating through the α→β phase transformation and the subsequent isothermal hold at the β-annealing temperature. It was found that during the ramp heating phase, the rotated cube texture component greatly expands from just below the β transus by broad front strain induced boundary migration (BF-SIBM), driven by a disparity in stored energy with neighbouring texture bands from the α and γ fibres. This subsequently sets up the necessary conditions for unstable coarsening of surviving grain clusters with predominately near α fibre orientations during the super-transus hold, in a process with similar characteristics to discontinuous recrystallisation. Humphreys’ mean field model of the stability of cellular microstructures, effectively explains the process by which these grain clusters, which have a lower misorientation range relative to the rotated cube component matrix, have a higher probability of entering a discontinuous growth regime, compared to other components from the α and γ fibres. Furthermore, the conditions that give rise to the development of ACG structures could be linked to the high strain rate and temperature experienced at the central mid-thickness of rolled plates.

High-Temperature Deformation Behaviors of the C-Doped and N-Doped High Entropy Alloys

High entropy alloys (HEAs) containing multi-principal metallic constituents have attracted much attention. A good understanding of their hot-deformation behavior and recrystallization mechanism is the prerequisite for microstructures tuning and for optimizing mechanical performance. Here, the flow behavior and recrystallization mechanism of the N-doped and C-doped face-centered cubic phase HEAs are produced at high temperatures by hot-compression at 1123–1273 K, with strain rates of 0.1–0.001 s−1. Constitutive equations were successfully constructed to reveal flow behavior, and stress-strain curves were predicted using strain compensated polynomial functions. Discontinuous and continuous dynamic recrystallization proceeded concurrently when compressed at a low temperature and high strain rate, whereas discontinuous recrystallization, which occurs at primary grain boundaries, became predominant at a high temperature and low strain rate, significantly contributing to the refinement and homogenization of the grains. For this reason, a relatively high temperature and a low strain rate, in which the recrystallized grains exhibit equiaxed morphology and very weak texture, are more suitable for refining grains. The average size of the grains was approximately 10 μm. This study sheds light on grain optimization and mechanical properties through thermomechanical processing.

On the association between microhardness, corrosion resistance and microstructure of probeless friction stir spot welded Al–Li joint

The precipitation behavior and development of grain structure have been investigated to reveal their association with the microhardness and corrosion resistance of probeless friction stir spot welded (P-FSSW) joint of an Al–Li alloy. Results identified the primary strengthening phase of T 1 (Al 2 CuLi) to be completely dissolved in the stir zone (SZ), while equiaxed grains were formed. Grain refinement was directly associated with the combined effect of continuous dynamic recrystallization and geometrized effect of imposed strain. However, as localized grain boundary bulging indicated, limited discontinuous recrystallization also participated in the microstructure evolution. The hardness dropped noticeably in the heat affected zone (HAZ) due to the weakening of precipitation and dislocation strengthening, which resulted from partial dissolution or coarsening of T 1 phase and recovery effect. Grain refinement and solution strengthening were responsible for the slight increase in hardness of the SZ. In addition, the SZ had minute increased pitting resistance due to the homogenization of intermetallic particles, precipitate dissolution and refined grains.

Grain Growth Mechanism of Lamellar-Structure High-Purity Nickel via Cold Rolling and Cryorolling during Annealing.

High-purity (99.999%) nickel with lamellar-structure grains (LG) was obtained by room-temperature rolling and cryorolling in this research, and then annealed at different temperatures (75 °C, 160 °C, and 245 °C). The microstructure was characterized by transmission electron microscopy. The grain growth mechanism during annealing of the LG materials obtained via different processes was studied. Results showed that the LG high-purity nickel obtained by room-temperature rolling had a static discontinuous recrystallization during annealing, whereas that obtained by cryorolling underwent static and continuous recrystallization during annealing, which was caused by the seriously inhibited dislocation recovery in the rolling process under cryogenic conditions, leading to more accumulated deformation energy storage in sheets.

Through-thickness shear texture of the twin-roll cast AA6016 sheet after asymmetric rolling and its recrystallization behavior

In this study, we investigate the through-thickness shear texture F{111}<112> and r-cube {001}<110> of the AA6016 twin-roll cast sheet under asymmetric rolling (ASR) via simulation and experiments and its recrystallization behaviors after annealing at 330 °C for 60 min. ASR can be achieved by controlling the velocity ratio of the upper and lower rollers to 2.0. Finite element (FE) simulations in case of ASR are used to determine the shear strain through the sheet thickness. Polycrystal simulations are conducted based on the FE results to predict the shear texture. Subsequently, the crystallographic texture of the sheet obtained with unidirectional ASR processes is evaluated. The experimental results show that the F-texture is obtained and that the inhomogeneity was distributed. The F-texture intensity of the sample near the lower roller (sample A) was greater than that of the sample near the upper roller (sample B). The simulation results are in good agreement with the measured results. However, the simulation results obtained with respect to the r-cube texture are greater than the measured results, resulting in considerable deviation. Further, the different recrystallization behaviors of the F-oriented grains (F-grains) are determined based on the sheet thickness. The F-grains associated with sample A can be obtained based on the rolling texture contributed by continuous recrystallization, whereas those associated with sample B can be achieved via discontinuous recrystallization. A considerably inhomogeneous microstructure and texture are observed through the sheet thickness after annealing.