Average Subgrain Size Research Articles

Subgrain Size Modeling and Substructure Evolution in an AA1050 Aluminum Alloy during High-Temperature Compression.

For materials with high stacking fault energy (SFE), such as aluminum alloys, dynamic recovery (DRV) and dynamic recrystallization (DRX) are essential softening mechanisms during plastic deformation, which lead to the continuous generation and refinement of newborn subgrains (2° ˂ misorientation angle ˂ 15°). The present work investigates the influence of compression parameters on the evolution of the substructures for a 1050 aluminum alloy at elevated temperatures. The alloy microstructure was investigated under deformation temperatures ranging from 300 °C to 500 °C and strain rates from 0.01 to 0.1 s-1, respectively. A well-defined substructure and subsequent subgrain refinement provided indication of the evolution laws of the substructure under high-temperature compression. Corresponding experimental data on the average subgrain size under various compression conditions were obtained. Two different independent average subgrain size evolution models (empirical and substructure-based) were used and applied with several internal state variables. The substructure model employed physical variables to simulate subgrain refinement and thermal coarsening during deformation, incorporating a corresponding dislocation density evolution model. The correlation coefficient (R) and root mean square error (RMSE) of the substructure-based model were calculated to be 0.98 and 5.7%, respectively. These models can provide good estimates of the average subgrain size, with both predictions and experiments reproducing the expected subgrain size evolution using physically meaningful variables during continuous deformation.

Microstructural evolution and mechanical behaviors of rock salt in energy storage: A molecular dynamics approach

The microstructure of rock salt significantly influences its macroscopic mechanical behaviors and deformation phenomena. Understanding the deformation and failure characteristics of rock salt at multiple scales is crucial for the secure and efficient functioning of energy storage in salt caverns. Although the macroscopic behaviors of rock salt are well understood, the microstructural changes occurring under uniaxial compression have not been thoroughly investigated. This study aims to investigate the evolving laws of rock salt microstructure and mechanical properties during the damage process, thereby providing a fundamental understanding of the underlying mechanism. To achieve this, a series of characterization tests on rock salt were conducted to study its microstructure and defects. Building on this, molecular dynamics simulations were utilized in rock mechanics to elucidate the mechanical behaviors, structural evolutions, and dislocation motions of rock salt during the damage process. The rock salt obtained from Qianjiang, China, is a polycrystalline material with an average subgrain size of 46 nm and an average dislocation density of 4.76 × 10−6 1/Å2. Uniaxial compression of single crystal NaCl exhibits three stages: elastic compression, rapid dislocation multiplication, and forest hardening. Scattered dislocations and isolated dislocation tangles trigger further plastic slippage, leading to decreased strength. Later, the formation of a dislocation cell network hinders further slip and reinforces the strength of rock salt. Plastic deformation is found to be a dominant factor in grain refinement and the formation of polycrystalline structures. Intergranular cracking results from cross-patterned dislocation lines on grain boundaries, which become vulnerable areas of the structure. This study describes the evolutionary process of rock salt microstructures and mechanical properties, identifies the micro-destruction mechanisms during the damage process at the ionic level, and provides insights into the micro-mechanical behavior of rock salt and for the design and stability assessment of underground energy storage facilities.

Biological and mechanical response of laser shock peening orthopaedic titanium alloy (Ti-6Al-7Nb).

This paper focuses on the evaluation of mechanical and biological properties of laser shock peening (LSP) orthopaedic grade Ti-6Al-7Nb alloy. LSP surface treatment was conducted at laser energy of 3 to 7 J with overlaps of 33%–67%, and with a 3 mm laser spot size. Cell viability on laser shock peened surface was evaluated through in-vitro MTT assay, using osteoblast-like MG63 cells for the first-time. Residual stresses, microhardness, microstructure, sliding wear and wetting properties were investigated. Compressive residual stresses were found at various depths due to controlling the LSP parameters, compared to the as-received surface. The laser shock peened surfaces were hardened from 365HV0.05 to 405HV0.05, while the as-received surface was 320HV0.05. The average sub-grain size was refined from 14% to 36% after LSP. The wear resistance was also controllable by altering LSP parameters. The MTT results show that the cell viability on the laser shock peened surfaces was comparatively lower than that of the untreated surface after 24 h. However, after 72 h, the cell viability on modified surfaces were significantly improved. This work indicated that laser shock peened surfaces have a strong potential to decrease the pain from orthopaedic implant failures and promote the cytocompatibility between the bone and implant.

Hot-deformation induced static recrystallization and nano-MX precipitation in a low activation martensitic steel

The static recrystallization and MX precipitation of a low activation martensitic (LAM) steel processed by different compression temperatures were studied. The result shows that at an identical duration of 200 s, the static recrystallization degree of steel decreases continuously from 96% to 62% and 25 % with decreasing compression temperature from 1050℃ to 950℃ and 850℃, respectively. Analysis shows that, with the decrease of compression temperature, the reduced recrystallization rate is mainly due to the decrease of temperature and the increase of nano precipitation content. After solution treatment, the sizes of grains, subgrains and the MX carbides decrease in the LAM steel with the decrease of compression temperature. After 1050 ℃ compression, the average size of grains, subgrains and MX carbides are 7 μm, 220 nm and 15 nm, respectively. However, in the 850 ℃ case, the corresponding size significantly decreases to 4.5 μm, 175 nm and 10 nm, respectively, which is mainly due to the lower recrystallization degree and the increase of nano precipitation content in the steel after compression. With the decrease of the compression temperature from 1050 ℃ to 950 ℃ and 850 ℃, the hardness of LAM steel after solid solution treatment increases from 4.0 GPa to 4.2 GPa and 4.5 GPa, mainly resulting from the refinement of grains, subgrains and MX carbides.

Microstructure refinement and mechanical properties of the NiCoMnIn alloy obtained by arc melting technique from mechanically alloyed powder

The Ni45.5Co4.5Mn36.6In13.4 alloy was produced by mechanical alloying during high energy ball milling for 70 h. Then, the powder of NiCoMnIn was cold compressed followed by melting of the green compact by vacuum arc melting technique. The structure and mechanical properties of the obtained alloy were systematically studied. The sub-grain refinement of the Ni45.5Co4.5Mn36.6In13.4 alloy produced by the arc melting from the pre-alloyed powder was observed. It was achieved due to the specific distribution of the γ, parent (L21) and martensite (14 M) phases. The average subgrain size was about 10 μm, which is 100 times lower than grain size observed in the reference bulk sample produced by conventional melting technique. The improvement in mechanical strength from 260 MPa to 1250 MPa for reference and bulk alloy prepared from powders respectively was achieved. Reduced Young’s modulus from nanoindentation experiment was lower in bulk alloy produced from pre-alloyed powder than in reference specimen.

Mechanism of crack initiation under high cycle fatigue through an EBSD based approach in a 10 wt% Cr steel

The study presents an insight into the mechanism of crack initiation under high cycle fatigue (HCF) and estimation of the initiation life thereof, using electron backscatter diffraction (EBSD) as an important tool in a 10% Cr ferritic steel. The localized plastic deformation facilitating crack initiation under HCF is found to be associated with dislocation multiplication and localized cyclic hardening. This process is found to occur concomitantly with the substructural development through the localized deformation leading to formation of new subgrains which act as barriers to the dislocation motion. The subgrain strengthening that arises as a consequence, adds to the local internal stress through dislocation pile-ups, aiding the process of crack initiation. The local internal stress is computed using the average subgrain size, which in turn is used to estimate the critical length required for the crack to self-propagate under the applied HCF stress, applying the principle of fracture mechanics. This concept is also utilized to identify the crack propagation threshold demarcating the regimes of propagating and non-propagating cracks.

Microstructure and Crystallographic Texture of Silicon Iron Modified by Torsion Under Quasihydrostatic Pressure

The electron backscatter diffraction, X-ray diffraction analysis, electromotive force instantaneous measurement, microhardness and coercive force measurement techniques are used to explore the development of the microstructure, crystallographic texture and physico-mechanical properties of silicon iron (Fe-3% Si) alloy under quasi-hydrostatic pressure in a Bridgman anvil. It is found that the alloy deformation is accompanied by its significant hardening. In-plane torsion test shows that the average grain size rapidly decreases down to 185 nm after a quater turn of the movable anvil. With the number of turns increased up to six the grain size gradually decreases down to 150 nm. At the same time, the average size of subgrains is less dependent on the deformation degree. The crystallographic texture evolution involves the formation of the strong {001} texture component after comparatively small megaplastic deformation followed by the simple shear texture formation. Such a behavior can be correctly described in terms of non-equilibrium thermodynamics.

Orientation Independent and Dependent Subgrain Growth during Iso-Thermal Annealing of High-Purity and Commercial Purity Aluminium

The orientation dependence on recovery has been studied in cold-rolled and annealed polycrystalline high-purity aluminium (99.99 wt%), binary Al-0.25Mn and commercial purity aluminium. The growth mechanisms were found to be independent of the alloy system and the microchemistry only influences the coarsening kinetics. Orientation-dependent subgrain growth, mainly studied in high-purity aluminium and measured in lamellar bands of uniform orientation, occurs in three distinct ways, depending of the size of the local orientation gradients. Following the evolution in average subgrain size and boundary misorientation by detailed electron backscatter diffraction (EBSD) characterization during annealing, it was found that the rate of subgrain growth in Cube- and Goss-oriented grains were faster than in the typical deformation texture components, particularly after an incubation time when discontinuous subgrain growth occurs. In commercial purity aluminium, general orientation-independent subgrain growth is faster than the orientation-dependent growth because more growth occurs in regions near high-angle grain boundaries separating differently oriented lamellar bands. It appears as if subgrains misoriented by more than 3.5° have a growth advantage over less misoriented subgrains, typically in the interior of lamellar bands. While the average boundary misorientations are decreasing, the individual boundary misorientations are increasing.

Structure of the Ni-Co-Mn-In alloy obtained by mechanical alloying and sintering

A polycrystalline Ni45.5Co4.5Mn36.6In13.4 alloy was obtained by mechanical alloying during high energy ball milling. As-milled powders after 2.5 h, 5 h, 10 h, 15 h, 20 h, 30 h, 40 h, 50 h, 60 h and 70 of milling were studied in terms of structure, particle size and morphology, martensitic transformation. Selected powders were cold pressed and two-step sintered at 1253 K for 0.5 h and then at 1173 K for 24 h, followed by quenching into the ice-water mixture. The structure was examined by X-ray diffraction and electron microscopy. After 30 h of milling, solid-solution of nanocrystalline NiCoMnIn alloy with disordered body-centered cubic structure was observed. The microstructure of sintered samples revealed precipitates of γ particles inside of the matrix B2 grains, creating ‘subgrains’ of the matrix. The estimated average size of subgrains was around 60-70 μm.

Formation of a thermally sustainable polygonization substructure with enhanced properties in electric arc coatings

The paper studies the possibility of forming electric arc steel sprayed coating from wires of grades 65G and Sv-08G2C with a partially thermally stabilized polygonal substructure due to additional deformation and heat treatment. It has been established that additional deformation by pressing 25% and 30% of electric arc steel coating from wire 65G and 20% and 30% of coatings from wire Sv-08G2S provides an opportunity to increase the duration of exposure of heat treatment for 15 ... 20 minutes without significant reduction of hardness due to the formation of partially stabilized substructure. The method of X-ray diffraction analysis has calculated the average size of sub-grains, the angle of divergence between them and the number of nanostructured elements in sprayed coatings. It has been shown that the average size of subgrains of electric arc coatings decreases with deformation and stabilization of the substructure by 40 ... 45% in comparison with coatings after spraying. Also, when carrying out the heat treatment and additional deformation, an increase in the number of nanostructured elements from 18% to 32 ... 35% is ensured and the average angle of subgrains divergence increases. The influence of surface plastic deformation by shot blasting processing on the possibility of forming a stable polygonization substructure in the coatings of 65G wire has been investigated. Shot blasting provides stabilization of the polygonal substructure during heat treatment to the duration of exposure 40 minutes. Experimental investigations of the influence of heat treatment, surface plastic deformation and combined deformation-heat treatment on the bond strength and wear resistance of the electric arc steel coatings from wire 65G have been carried out. t has been established that carrying out heat treatment of 65G wire coatings provides an increase in the bond strength by 30% compared to the coatings after deposition by reducing internal stresses. Heat treatment of additionally deformed coatings provides a significant increase in bond strength compared to heat treated coatings without deformation. It is shown that heat treatment provides an increase in the wear resistance of coatings from 65G by 45% compared with the state after spraying.

Wear Resistance and Tribological Features of Ultra-Fine-Grained Al-Mg Alloys Processed by Constrained Groove Pressing-Cross Route

In the present study, the wear behavior of ultra-fine grained (UFG) Al-Mg alloys produced by a severe plastic deformation (SPD) method was assessed and compared against the annealed coarse-grained alloy. To this end, weight loss, wear resistance, friction coefficient, and morphology of the worn surfaces was investigated. Constrained groove pressing-cross route (CGP-CR) process, an SPD technique, was implemented at ambient temperature up to two passes to impose an equivalent plastic strain of about 4.64. Formation of a UFG structure with an average sub-grain size of ~ 350 nm with an enhanced tensile strength of up to ~ 225 MPa and indentation hardness of up to ~ 95 HV were achieved upon two passes of CGP-CR process. The pin-on-disk dry wear sliding testing was conducted up to a distance of 1000 m under normal loads of 5, 7, and 9 N at a constant sliding speed of 0.5 m/s. The trends measured for the evaluation of wear properties/mechanisms are discussed based on the microstructural features and mechanical property of UFGed alloys. The results showed that by employing the CGP-CR process and through the formation of UFG structure, the wear resistance was considerably increased. This was even beyond two times (~ 100%) larger depending on the normal loading with the lowest coefficient of friction around 0.6. Observation and study of the morphology of the worn surfaces under field emission-scanning electron microscopy (FE-SEM) revealed a change in the wear mechanism from sticking followed by formation of plastic deformation bands and delamination in the coarse-grained annealed alloy into a combined abrasive-adhesive behavior in the UFG material.

GROWTH PROCESSES OF SUBGRAIN AND MORPHOLOGY EVOLUTION IN THE SYNTHESIS OF Β-SiC FILMS AT (111) Si IN THE ATMOSPHERE OF METHANE

By the methods of transmission electron microscopy, high energy electron diffraction, atomic force microscopy, and Auger electron spectroscopy, the article studies the phase composition, orientation, substructure, and morphology of the films formed during pulsed photon treatment (PPT) by radiation of xenon lamps of silicon (111) Si substrates in an atmosphere of methane. We have established that in the range of the energy density of radiation (Ep) supplied to the substrate with a thickness of 0.45 μm for 3 s from 269 to 284 J cm-2 the oriented nanocrystalline films are formed on both surfaces of the substrates both from the irradiated and non-irradiated side β-SiC thickness of about 150 nm. In this case, the synthesis of films on the irradiated side is carried out with the possible participation of photon activation of processes and on the reverse side – only by thermal activation (short-term heat treatment (SHT). With an increase in the energy density of radiation in β-SiC films, the average subgrain size on the irradiated side is shown to increase from 4.2 nm (Ep = 269 J ·cm-2) to 7.9 nm (Ep = 284 J ·cm-2) and on the non-irradiated side 3.9 to 7.0 nm respectively. The surface roughness of the β-SiC surface proceeds consequentially on the irradiated side from 19 nm (Ep = 269 J ·cm-2) to 60 nm (Ep = 284 J ·cm-2) and on the non-irradiated side from 11 nm to 56 nm respectively. Based on the temperature dependences of the average grain size and roughness, we have estimated the apparent activation energies of the processes. The activation energy of subgrain β-SiC growth is practically independent of the activation method and is 1.3 eV. The activation energy for the evolution of roughness is 2.5 eV at a PPT and 3.5 eV at a SHT.

Activation energy of subgrain growth process and morphology evolution in β-SiC/Si(111) heterostructures synthesized by pulse photon treatment method in a methane atmosphere

Single-phase β-SiC films were grown by the pulsed photon treatment (PPT) of (111)Si wafers with the use of xenon lamp radiation in a methane atmosphere. Study of phase composition, structure and morphology revealed that β-SiC oriented nanocrystalline films are formed onto both non-irradiated and irradiated surfaces under the radiation energy range from 269 to 284 J cm−2 supplied for 3 s. The non-irradiated side was undergone the rapid thermal annealing (RTA). It is demonstrated that the average subgrain size increases from 4.2 nm (Ep = 269 J cm−2) to 7.9 nm (Ep = 284 J cm−2) and from 3.9 to 7.0 nm for the irradiated and non-irradiated sides respectively when radiation energy density rises. The surface roughness of β-SiC films increases gradually from 19 to 60 nm and from 11 to 56 nm on irradiated and non-irradiated sides respectively in the same radiation energy density range. The β-SiC subgrain growth activation energy is 1.3 eV and it does not depend on the activation method. The surface roughness evolves with the activation energy of 2.5 eV and 3.5 eV for PPT and RTA respectively.

Microstructural investigation of Al-Mg/B4C composite deformed at elevated temperature

The microstructure evolution of Al-3wt.%Mg reinforced with 10 vol% B4C during isothermal compression at temperatures ranging 300–500 °C at strain rates of 0.001–10 s−1 was investigated by electron backscatter diffraction (EBSD). According to the results, at strain rates lower than 0.01 s−1 and temperatures higher than 400 °C, the grain size distribution in the microstructure is uniform, dynamic recovery is the predominant softening mechanism and continues recrystallization through lattice rotation is responsible for grain refinement. However, during deformation at higher strain rates or lower temperatures, deformation zones appeared in special locations around particles where microstructure is formed by recovered and hardened grains, and particle stimulating nucleation leaded to partially discontinues dynamic recrystallization which in turns promoted finer average grain and sub-grain size than those in single phase Al-Mg alloy. Moreover, it was found that the variation of grain and sub-grain size with deformation parameters (Zener-Holloman parameter (Z)) can be described by a power law type equation rather than by an initially expected exponential expression.

Hydrogen Embrittlement of Ultrafine-Grained Austenitic Stainless Steels

Abstract The effect of electrochemical hydrogen-charging on tensile properties, mechanisms of plastic deformation and fracture micromechanisms was studied using two ultrafine-grained (UFG) Cr-Ni austenitic stainless steels. UFG austenitic structures with an average subgrain size of 200 nm for CrNiMo (316L-type) and 520 nm for CrNiTi (321-type) steel were produced using hot-to-warm ABC-pressing. Hydrogen-charging up to 100 hours weakly influences stages of plastic flow, strength properties and elongation of the UFG steels. TEM analysis testifies to hydrogen-assisted partial annihilation and rearrangement of dislocations into dislocation tangles, and to hydrogen-induced variation in ratio of low- and high-angle misorientations in UFG structure of both steels. Hydrogen-alloying promotes mechanical twinning and deformation-induced γ ® e martensitic transformation in the UFG steels under tension. Ultrafine-grained CrNiTi steel with lower stacking fault energy (SFE) is more susceptible to mechanical twinning and deformation-induced γ ® e martensitic transformation in comparison with CrNiMo steel with higher SFE. The micromechanism of the fracture in hydrogen-assisted surface layers of the steels is compositional, grain-size and hydrogen content dependent characteristic. The present results demonstrate that the steels with UFG structure possess higher resistance to hydrogen embrittlement compared to coarse-grained analogues.

The Influence of Casting Methods on Microstructure of Al-Mg-Sc-Zr Alloy

Two methods of fabrication of Al-Mg-Sc alloy are compared - conventional casting followed by cold-rolling and twin-roll casting. To the advantages of twin-roll casting belong the lower material and energy requirements during the production. However, twin-roll cast material exhibits different initial microstructure and routes established for conventionally cast materials cannot be applied. In twin-roll cast material the distribution of primary particles is more inhomogeneous - they form segregation near the center and edges of the sheet and their average size is smaller. On the contrary, the average sub-grain size is much higher in the twin-roll cast material.

Hydrostatic cyclic expansion extrusion (HCEE) as a novel severe plastic deformation process for producing long nanostructured metals

In this paper, hydrostatic cyclic expansion extrusion (HCEE) is developed as a new severe plastic deformation technique for processing of the relatively longer ultrafine grained samples. Increasing the length of the processed sample, decreasing the processing load astonishingly, and increasing the hydrostatic stresses are the main advantages of HCEE. In this process, pressurized hydraulic fluid surrounded workplace played the primary role in reducing the friction load and in reducing consequently total load. The HCEE process was applied to commercial pure aluminum 1050 samples at room temperature, and then microstructural evolution and mechanical properties were examined. Microstructure analysis using back-scatter diffraction (EBSD) revealed that a significant grain refinement is achieved after the HCEE process. The average size of grains and subgrains decreased to ~700 nm after two passes of the HCEE process from the initial value of 50 µm in the unprocessed sample. Yield and ultimate strength were increased from 40 MPa and 52MPa to 125 and 137 MPa after two passes of HCEE process. Also, microhardness was increased from 36 HV to 45 HV after the first pass. The process seems to be very promising for industrial application of SPD processing which suffer from the main challenge of limited sample size.

Flow Behavior and Microstructural Evolution of 7A85 High-Strength Aluminum Alloy During Hot Deformation

Hot deformation behavior of 7A85 high-strength aluminum alloy was investigated at 593 K to 713 K (320 °C to 440 °C) and 0.01-10 s−1. The manifestation of flow curves was related to the strain rate. Typical single-peak curves were shown below 10 s−1, while two stress peaks appeared in the case of 10 s−1 and the second peak strain was almost three times larger than the first one. A constitutive equation considering the effect of strain was developed. Flow stress values predicted by the constitutive model demonstrated a good agreement with the experimental results over the entire range of strain rates and temperatures. Microstructure characterization revealed that dynamic recovery (DRV) and continuous dynamic recrystallization (CDRX) which depended on the Zener–Hollomon parameter (Z) closely, co-occurred at large strain (e = 0.7). With decreasing Z-value, the dominant dynamic restoration mechanism gradually transformed from DRV to CDRX. The average subgrain size (d sub) showed a power-law relationship with Z. Recrystallization was sensitively dependent on the strain rate at above 683 K (410 °C). The fine equiaxed grains appeared at original grain boundaries and in deformed grains interior owing to CDRX. The high-curvature subgrain boundaries can also cause the nucleation of recrystallization within deformed grains.

Change in Dislocation Structure and Phase Composition of 1565Ч Alloy Exposed to Ion Irradiation (Cu + Pb)

Background/Objectives: Using electron microscopy, it was revealed that exposure to ion irradiation (Cu + Pb) with an energy of 35 keV of samples sized 25 × 25 × 3 mm of 1565ч industrial aluminum alloy after cold rolling, leads to a significant narrowing of the boundaries of intragranular cellular dislocation structure and increase in the extent of its regularity. Methods/Statistical Analysis: We have studied samples of 1565ч alloy sized 25 × 25 mm 2 cut from non-clad sheets of a thickness of 3 mm, a change in the structure of cold-worked 1565ч alloy exposed to the beams of accelerated ions (Cu + Pb) with an energy of 30 keV at the densities of ion current of 100, 200 and 300 μA/cm 2 and irradiation doses of 1016 and 1017 cm -2 . Irradiation with pulsed beams of ions (Cu + Pb) was conducted at the setup for ion beam implantation equipped with ion source based on plasma arc in vacuo. Electron microscopic study by the method of thin foils was conducted at JEM-2100 transmission electron microscope. Findings: It was found that irradiation of cold-worked clad 1565ч alloy with copper and lead ions does not lead to a fundamental change in its structure compared to the structure existing in the deformed condition: cellular dislocation structure remains. With increase in ion current density and irradiation dose, the cellular structure becomes more regular - well-formed cells are observed throughout almost the entire volume of the sample. The average width of dislocation-free regions reaches 2.5 μm at the width of the boundaries not exceeding 0.6 μm. The effect of accelerated ions (Cu + Pb) (E = 30 keV, j = 100 μA/cm 2 ) on the alloy without the cladding layer even at a dose of 1016 cm -2 leads to formation of the developed subgrain structure in initially deformed alloy. The average size of subgrains with interlacements of dislocations varies in the range of 0.6 - 2.2 μm. In other words, a polygonal structure forms in the alloy similar to the structure forming at the initial stages of recrystallization annealing. Applications/Improvements: This applies to many industries associated with the development of high-tech and energy-saving technologies as well as addressing environmental problems.

Influence of rolling parameters on dynamically recrystallized microstructures in AZ31 magnesium alloy sheets

Abstract Conventional rolling experiments via the embedded pin in rolling sheet method were carried out at different reduction rates, starting rolling temperatures, and rolling speeds, and the effects of rolling parameters (i.e., temperature, equivalent strain, and rolling time) on dynamically recrystallized (DRX) microstructures of AZ31 alloy during hot rolling were studied quantitatively. The temperature-strain dependence of the high-angle grain boundary fraction (HAGB%) was examined through electron backscattered diffraction. Results showed that as-rolled microstructures with high HAGB% may be obtained under average rolling temperatures of 270–320 °C, equivalent strains higher than 0.8, and a rolling speed of 246 mm/s. These results may be related to the DRX kinetics and dynamic recovery which are controlled by deformation temperature and strain. HAGB% decreased with increasing rolling time (decreasing rolling speed), which is attributed to dynamic recovery, and the recrystallized grain size decreased as rolling time increased. However, further increases in rolling time increased average grain sizes but decreased mean subgrain sizes; these results are attributed to increases in the low-angle grain boundary (LAGB) length per unit area with rolling time. LAGB formation was controlled by dynamic recovery, which consistently follows polygonization or formation of new subgrains inside larger grains; hence, average subgrain sizes decreased with the rolling time. The effect of dynamic recovery on HAGB and LAGB formation and their related mechanisms over a wide range of strains and temperatures were discussed in detail.