High-temperature Laser Scanning Confocal Microscopy Research Articles

A new insight on the diffusion growth mechanism of intermetallic compounds in Al-Er system

The diffusion growth of intermetallic compounds in Al-Er alloys are closely related to the properties of the alloys. The current work aims at explaining the dominance of Al3Er in the Al-Er alloys precipitation phases and the interface thin layer phenomenon by diffusion couple technique, estimating the parabolic growth constant and diffusion activation energy of intermetallic compound in Al-Er diffusion couples to provide theoretical guidance for the design of new Al-Er alloys. In this work, Al-Er diffusion couples were successfully prepared by casting-cladding method in the atmosphere. The growth of Al-Er intermetallic compounds at diffusion couple interface during annealing were observed and recorded by High-Temperature Laser-Scanning Confocal Microscopy at 673, 698, 723 and 748 K respectively. The results show that the growth characteristics of Al-Er intermetallic compounds were accord with layer-terraced growth during annealing. The thickness of intermetallic compound was linear with the square root of time at experimental temperature. The intermetallic compound layer was composed of Al3Er and a very thin AlEr phase. The parabolic growth constants of Al3Er phase at 673, 698, 723 and 748 K were 1.017 × 10−14, 1.609 × 10−14, 3.111 × 10−14 and 4.76 × 10−14 respectively. The activation energy of Al3Er phase was (88.4 ± 5.3) kJ/mol and the pre-exponential factor was 7.126 × 10−8 m2/s.

In-situ observations of solidification process of Fe–Al–Ta eutectic alloy

The Fe–Al–Ta eutectic alloy can be formed by eutectic reaction in order to improve the performance of Fe–Al intermetallic compounds, and thus it is important to further clarify the crystal growth mechanism of the Fe–Al–Ta eutectic alloy during solidification. Thus, the melting and solidification temperatures of the Fe–Al–Ta eutectic alloy were determined by differential scanning calorimetry, and the melting and solidification processes of the Fe–Al–Ta eutectic alloy were observed in situ by high-temperature confocal scanning laser microscopy. In addition, the solidified structure of the Fe–Al–Ta eutectic alloy was observed and characterized by scanning electron microscopy and energy dispersive spectroscopy. No other types of phase transitions were found in the Fe–Al–Ta eutectic alloy when the temperature was below 1600 °C. The reinforced phase exhibited a certain orientation after solidification, and the microstructure at the center of the eutectic cell was much more regular than that at the grain boundary. The effect of the cooling rate on the microstructure morphology and the formation mechanism of the irregular divorced eutectic were analyzed.

Agglomeration behavior of rare earth inclusions and alumina inclusions at the interface between argon and molten steel

Nozzle clogging frequently occurs in steel containing rare earth (RE) due to the aggregation of RE inclusions, which seriously interferes with the application of RE in steel. To provide insights into nozzle clogging, the agglomeration behavior of inclusions in RE-containing steel was investigated by laboratory experiments and theoretical calculations. High-temperature confocal laser scanning microscopy (HT-CLSM) was applied to observe the behavior of inclusions at molten steel surfaces and their interactive forces. Kralchevsky–Paunov (K–P) model was used to predict the capillary force acting on different inclusions. The results show that the interactive forces that acted on inclusions were investigated as a function of inclusion size, inter-distance, and inclusion composition. It is found that the capillary force acting on the inclusions decreases in the order of Ce2O3 > CeAlO3 > Al2O3. This study verified the applicability of the K–P model in RE-containing steel, which can provide theoretical support to help solve the nozzle clogging problem during rare earth steel production.

In situ observation of bainitic transformation behavior in medium carbon bainitic steel

The bainitic transformation behavior of samples with different scales was observed with dilatometer (DIL), high-temperature laser scanning confocal microscope (LCSM), and environmental transmission electron microscope (ETEM). Results show that the bainitic transformation behavior varies according to the geometrical size of samples, and it is mainly manifested in transformation units and growth rates of units. The nucleation and growth processes of finer bainitic subunits, accompanied by dislocation movement, were observed by ETEM. At the same time, the radial lengthening and broadening rates of bainitic ferrite (BF) plates were quantitatively measured. The former is 82 times the latter. The broadening time of BF plates accounts for 97.3% of the total time of the growth.

Effect of tin microalloying on the microstructure of low-carbon free-machining steels

Sn is a well-known grain boundary segregation element that improves the machinability of steel. Sn has been considered as a replacement for Pb in super-free-machining steels. The effect of Sn on the microstructure of the Fe-0.05C-0.03Si-1.28Mn-0.36S-0.05P base composition containing 0.0002 (without addition), 0.062, 0.12, and 0.18 Sn (wt.%) low-carbon free-machining steels was investigated though thermodynamic calculations, optical microscopy, scanning electron microscopy, transmission electron microscopy, electron probe microanalysis, and high-temperature laser scanning confocal microscopy. The microstructure of the free-machining steels was composed of α-ferrite, pearlite, and manganese sulfide. Sn significantly decreased the pearlite content of the steels. Most of the Sn was dissolved in the matrix, and the remainder was dissolved in manganese sulfide. No FeSn intermetallic compound precipitation was observed through transmission electron microscopy, but a significant strengthening effect was observed in α-ferrite. Sn had little effect on the solidification behavior or sulfide precipitation behavior of the steels when its content was lower than 0.2 wt.%. Similar to Al and Si, Sn is a ferrite-stabilizing element that expands both the δ-ferrite and α-ferrite phase regions, promotes α-ferrite formation, and inhibits carbide precipitation. Sn segregates at the interface, decreasing the interfacial energy and promoting the Widmanstätten ferrite phase transformation. A much lower cooling rate than that of Sn-free free-machining steels should be adopted to restrain the formation of Widmanstätten ferrite after hot rolling. Sn addition greatly improved the machinability of the experimental steels.

In-situ observation of peritectic solidification of Fe-Mn-Al-C steel with medium manganese

The design of the continuous casting process for the third generation of Fe-Mn-Al-C steel with medium manganese should be based on the understanding of the peritectic solidification mechanism. So, in the present study, Fe-5.56Mn-0.078Al-0.157C (wt%) steel was taken as the research object. By means of high-temperature confocal scanning laser microscopy (HT-CSLM), Thermo-Calc thermodynamic software and optical microscopy, the peritectic solidification process and microstructure characteristics of the medium manganese steel at different cooling rates were studied and revealed. And thus, the influence of the cooling rate on the peritectic solidification mechanism was clarified. Meanwhile, the kinetics of the γ-Fe grain wrapping the δ-Fe grain and the subsequent growth were determined. The results show that at low cooling rate of 10 °C/min, the initial δ-Fe phase is cellular. The γ-Fe phase firstly nucleates at the L/δ interface, and then grows along the δ/L interface until the L and δ-Fe phases are separated. Subsequently, the peritectic transformation occurs, that is the L and δ-Fe phases are directly transformed into the γ-Fe phase. Under the conditions with higher cooling rates of 20 and 30 °C/min, when the γ-Fe phase separates the L and δ-Fe phases completely, multiple γ-Fe grains form in a single δ-Fe grain at the same time, and the whole δ-Fe grain is covered within a very short time, which is the typical massive-like transformation. In the initial stage of the peritectic reaction, the linear velocity of the γ-Fe phase wrapping the δ-Fe phase is inversely proportional to the cooling rate, which is closely related to the size and morphology of δ-Fe grains. At cooling rates of 10, 20 and 30 °C/min, the initial migration rates of the δ/γ interface are 45.9, 8.9 and 12.5 µm/s, respectively. At higher cooling rates, the occurrence of the massive-like transformation greatly promotes the peritectic transformation, and the migration rate of the δ/γ interface increases to 16.7 and 17.8 µm/s. The initial migration rates of the γ/L interface are 6.0, 1.8 and 6.5 µm/s, respectively. It is found that the migration rate of the δ/γ interface is much larger than that of the γ/L interface. Dendrite etching experiment in the top, bottom and longitudinal sections of the medium manganese steel samples shows that the larger the cooling rate, the finer the solidification structure. • The δ/L interface of Fe-5.56Mn-0.078Al-0.157C (wt%) steel becomes more unstable with the increase of the cooling rate. • The mechanisms of the peritectic solidification of the medium Mn steel at different cooling rates are revealed. • Kinetics of the γ-Fe phase wrapping δ-Fe phase and then growing into δ-Fe and L phases are measured for the medium Mn steel. • The relationships between the dendrites arm spacings of the medium manganese steel and cooling rates are presented.

Study on microsegregation and homogenization process of a novel nickel-based wrought superalloy

In this paper, the as-cast microstructure, microsegregation, precipitates and suitable homogenization process of a novel Ni-based wrought superalloy prepared by vacuum induction melting (VIM) + vacuum arc remelting (VAR) were investigated by optical microscope (OM), scanning electron microscope (SEM), electron probe microanalysis (EPMA), differential scanning calorimetry (DSC), high temperature confocal laser scanning microscope (HT-CLSM) and thermal simulation compression. The results show that severe element segregation exists in the ingot. Nb, Ti and Al are mainly segregated in the interdendritic region, while W is mainly segregated in the dendrite arm. The precipitates in the alloy mainly include non-uniform γ′ strengthening phase, coarse (γ + γ′) eutectic phase and MC carbide, among which, the redissolution temperature range of γ′ phase is 1060–1220 °C; the (γ + γ′) eutectic phase can be redissolved obviously above 1180 °C but melted into liquid at 1250 °C; the redissolution temperature range of MC carbide is 1349–1358 °C, exceeding the solidus temperature of the alloy. After homogenization at 1220 °C/10 h, all the γ′ phase and most of the (γ + γ′) eutectic phase can be redissolved, and the element segregation can be significantly alleviated, moreover, the hot deformation resistance of the alloy is lower and the dynamic recrystallization (DRX) degree is higher, indicating that 1220 °C/10 h is an ideal single-stage homogenization process.

Investigation into the Temperature of Metallic High-Temperature Confocal Scanning Laser Microscope Samples

Investigation into the Temperature of Metallic High-Temperature Confocal Scanning Laser Microscope Samples

Numerical Treatment of Oxide Particle Dissolution in Multicomponent Slags with Local Gibbs Energy Minimization

Herein, a diffusion model for the dissolution of oxide particles in multicomponent slag systems is developed. It is assumed in this model that a sharp‐interface separates the solid particle from the liquid slag. Minimization of the Gibbs energy provides the conditions at the interface. The differential equations for multicomponent diffusion in the liquid slag are solved numerically via a finite‐difference scheme. It is indicated via parameter studies that the diffusion controlled dissolution kinetics may result in strongly different dissolution profiles depending on the initial conditions. It is demonstrated that the rate‐controlling dissipative process is the diffusion of components for cases where earlier investigations claimed that a coupled diffusion‐reaction process is in charge of the dissolution kinetics. Eventually, the numerical results are compared to data obtained from high‐temperature laser scanning confocal microscopy (HT‐LSCM) experiments.

Image Processing Procedure to Evaluate Inclusion Dissolution in a Slag Observed by High-Temperature Confocal Scanning Laser Microscopy

In situ study of the inclusion dissolution behavior in a slag utilizing high-temperature confocal scanning laser microscopy helps to understand the phenomenon of the removal of non-metallic inclusions from liquid steel before the casting process. The current work introduces an image processing procedure to automate and measure the inclusion diameter during its dissolution. Silica and alumina particle dissolution were considered as they appear differently when suspended in the slag (bubble-like transparent and solid-like opaque, respectively). The procedure consists of two parts: (1) morphological isolation and construction of the inclusion, and (2) inclusion diameter calculation. The inclusion diameters could be successfully measured over a series of images and showed good agreement with the manually measured diameters. The image processing procedure has the advantages of significant time saving and standardization compared to manual measurements.

In-situ study on γ phase transformation behaviour of γ-TiAl alloys at different cooling rates

γ-TiAl-based alloys are promising lightweight high-temperature structural materials, and the transformation from the α parent phase to γ lamellae during the cooling process has a great influence on the microstructures and mechanical properties of TiAl alloys. In this paper, an in-situ observation technique, high-temperature laser scanning confocal microscopy (HTLSCM), was utilized to investigate the continuous cooling transition (CCT) from the α phase in three compositions. The nucleation and growth behaviors of γ lamellae were studied at several moderate cooling rates. In addition, the processes of helium gas quenching for three alloys were investigated, and the massive transformation was observed in Ti–49Al. CCT diagraphs were concluded for three alloys. The Vickers hardness of TiAl alloys subjected to different cooling rates was tested, and it was found that the hardness of alloys was enhanced with increasing cooling rate due to the refinement of lamellar spacing.

Origin of fine equiaxed grains in industrial low-temperature grain-oriented silicon steel normalized sheet and their influence on magnetic properties

In the industrial low-temperature grain-oriented (LTGO) silicon steel normalized sheet, there are a certain number of fine equiaxed grains distributed along the rolling direction. However, the formation mode of the fine equiaxed grains and the influence of them on magnetic properties have not yet been well understood. In the present work, the above issues were investigated using field emission scanning electron microscopy (SEM), field emission transmission electron microscopy (TEM), X-ray diffraction (XRD), high temperature confocal scanning laser microscopy (HTCSLM), etc. It was found that (1) the fine equiaxed grains could be divided into many grain colonies according to grain orientation, and within each colony, the grain orientations were similar; (2) during normalizing, the fine equiaxed grains were mainly generated inside the elongated deformed grains which contained a large number of subgrains; (3) the amount of α → γ phase transformation during the normalizing was very small. Therefore, it can be inferred that the fine equiaxed grains were mainly produced by subgrain coalescence, rather than by phase transformation. Moreover, γ-grain (〈111〉 // ND) colonies with ideal grain size could be formed in the fine equiaxed grain regions after ideal normalizing process. Due to the heredity of microstructure and texture, γ-grain colonies, which can facilitate the formation of the precise Goss texture ({110} 〈001〉 ) during high-temperature annealing, were formed in the primary recrystallized matrix after cold rolling, decarburizing and nitriding, as a result, the magnetic properties of the final product were significantly improved. The present work can provide help to further improve the understandings of the microstructural evolution in the LTGO silicon steel normalized sheet and the influence of normalized microstructure on magnetic properties.

Improving mechanical properties in high-carbon pearlitic steels by replacing partial V with Nb

The effects of combined addition of niobium (Nb) and vanadium (V) on the transformation, microstructure and mechanical properties of high-carbon pearlitic steels were investigated. In-situ observations on a high-temperature laser scanning confocal microscope (LSCM) were conducted to study the pearlitic transformation, the results from which indicate that single V or combined Nb and V addition led to higher transformation temperature and more pearlitic nucleation sites. But the growth rate of pearlite was significantly impeded due to the smaller diffusion coefficient of carbon, resulting in the refinement of the interlamellar spacing and nodule size of pearlite. In addition, compared to the base steel, single V addition in high carbon pearlitic steels was beneficial to the increase of strength, but it deteriorated the toughness, whereas the composited addition of Nb and V resulted in the increase of strength without the expense of the toughness. It is concluded that replacing part V with similar content of Nb is very promising since the impact toughness of the Nb + V steel is increased by 21% without the expense of the strength compared to the V-microalloyed steel. Nb and V strengthened pearlitic steels primarily due to the precipitation of M(C,N), thinner pearlite interlamellar spacing and smaller pearlite nodule size. Compared to the V steel, the improvement of toughness in Nb + V steel was mainly attributed to the smaller nodule size and more uniform grain size distribution. In summary, under the premise of similar microalloying element amount in high-carbon (∼0.77 wt%) pearlitic steels, replacing part V with Nb is beneficial to obtain the finest microstructure and the best comprehensive mechanical properties.

Analysis on phase nucleation in Sn-Ni peritectic alloy combining confocal laser scanning in-situ observation and differential scanning calorimetry

The analysis of the phase nucleation requires not only the in-situ images but also the accurate nucleation information. Thus, the nucleation of both the primary Ni3Sn2 and peritectic Ni3Sn4 phases were studied during peritectic solidification of Sn-Ni alloy using the high temperature confocal laser scanning microscope (HT-CLSM) and differential scanning calorimetry (DSC). The results by both methods confirm that the nucleation undercooling ∆T of the solid phases decrease with increasing cooling rates, which is demonstrated to be caused by higher concentration difference at larger cooling rates. Besides, the freezing range of the alloy is also found to decrease with the increase in cooling rate. However, the nucleation undercooling of the peritectic Ni3Sn4 phase determined by HT-CLSM is larger than that by DSC at each cooling rate. This is attributed to the slower capture of peritectic reaction when using HT-CLSM. Furthermore, the nucleation of peritectic Ni3Sn4 phase is confirmed to be controlled by the heterogeneous nucleation on primary Ni3Sn2 phase by comparison between the HT-CLSM observation and DSC result. In addition, the wetting angles for heterogeneous nucleation of both phases which are important parameters in analyzing the nucleation of solid phases were determined through the entropy of solidification data from the DSC results. The smaller wetting angle of peritectic Ni3Sn4 phase as compared with that of the primary Ni3Sn2 phase further proving the smaller nucleation undercooling of Ni3Sn4 phase during solidification.

Artificial Inclusion Environments—Replicating Industry in the Laboratory

The authors present a series of complementary test methods which were developed and used to investigate reactions between high aluminium steel and silica rich inclusions. Non-metallic inclusions (NMIs) cause many defects in the final steel product, therefore the ability to track their size, morphology and composition and correlate this with fundamental reaction kinetics provides important knowledge to support the production of clean quality steel products. Novel steel grades such as TRIP, TWIP and low-density steels have high aluminium contents; aluminium is a readily oxidisable species presenting the potential for instability and excessive reaction with commonly used mould powders that contain silica. A novel combination of techniques including HT-CLSM (High-Temperature Confocal Laser Scanning Microscope), XCT (X-ray computed tomography) and SEM/EDS (scanning electron microscopy/electron dispersive spectroscopy) have been used to study the interaction of entrained mould powder inclusions with steel at high temperatures simulating industrial conditions. This report presents a discussion on the development of techniques and samples to achieve representative and repeatable results that can provide information on the complex chemical and physical interaction phenomena with confidence. Each experimental technique had its own learning points and consequent results. Outcomes presented include possible confirmation of the chemical reaction rate controlling step being aluminium mass transfer; heterogeneous local environmental conditions including fluidity and chemical composition; and occurrence of spontaneous emulsification where the mould powder inclusion breaks apart into a cloud of smaller fragments.

Systematic study on orientation relationships between acicular ferrite and Ti-Mg oxide at different cooling rates in low-carbon steel

In this paper, the influence of cooling rate on acicular ferrite (AF) nucleation and growth on Ti-Mg oxide was studied using high-temperature confocal laser scanning microscopy. The compositions and elemental distributions of the inclusions were studied via electron probe microanalysis, and the crystallographic orientation relationships between AF and inclusions were investigated systematically via electron back scattered diffraction. The results indicated that the initial transformation temperature of AF decreased from ~656 to ~609 °C and the growth rate of AF raised from 6.74 to 55.52 μm/s as the cooling rate increased from 1 to 12 °C/s. The area fraction and the nucleation probability of AF reached a maximum at 2 °C/s, which was the most suitable cooling rate for AF formation. The Ti-Mg-Mn-O, Ti-Mg-Mn-O·TiN and Ti-Mg-Mn-O·MnS inclusions in Ti-Mg deoxidized steel were all effective for AF nucleation. For the four samples at different cooling rates, all AF grains had four kinds of orientation relationships with Ti-Mg-Mn-O oxides: Baker–Nutting (B-N), Nishiyama–Wasserman (N-W), {100} Ferrite ║{110} Oxide , and irrational orientation relationships. The {100} Ferrite ║{110} Oxide orientation was also a common parallel relationship between the B-N and N-W orientation relationships. The lattice mismatch between the AF and oxide was low, and the interface between the AF and oxide was close to a coherent interface when the first three kinds of orientation relationships were adopted. The formation of a Mn-depleted zone (MDZ) around Ti-Mg-Mn-O oxide could increase the driving force of ferrite formation, and it contributed more to the nucleation of those AF grains that had no orientation relationships with oxides. • The nucleation and growth behaviors of acicular ferrite on Ti-Mg oxides at different cooling rates were observed. • Orientation relationships between acicular ferrite and Ti-Mg oxides were examined via electron back scattered diffraction. • The nucleation mechanisms of acicular ferrite induced by Ti-Mg oxides were discussed in detail.

Silicon recovery from Si sawing waste through slag refining

• Slag refining was employed for Si recovery from Si saw waste because of θ SiC/ CaO–SiO2–MgO < θ SiC/Si . • The movement and dissolution behaviors of SiC were observed in situ and in real-time using HT-LSCM. • A prolonged slag refining time was conducive to increasing the SiC removal efficiency. Recycling Si from Si sawing waste is a good approach aiming at meeting the rapidly increasing demand for Si, and the separation of Si and SiC particles plays a key role in the production of high-quality Si. In this work, Si was successfully recovered from Si sawing waste by using a CaO–51mol%SiO 2 –15mol%MgO slag. This recovery included measurement of the contact angle between a CaO–SiO 2 –MgO slag and SiC using the sessile drop method. The results, θ SiC/SiO2–CaO–MgO < θ SiC/Si (i.e., 21.7° < 38°) at 1753 K, confirmed the feasibility of applying the slag refining technique to SiC particle removal. Furthermore, with the help of high-temperature laser-scanning confocal microscopy, the movement and dissolution behaviors of SiC were observed in situ and in real-time. A prolonged slag refining time provided sufficient time for SiC particle transfer across the Si/slag interface and dissolution in slag, thereby resulting in a high SiC particle-removal efficiency.

Influence of Inclusions on the Nucleation of Acicular Ferrites in a Ti–Zr‐Bearing Steel

Laboratory experiments are conducted to study the influence of inclusions on the nucleation of acicular ferrite in Ti–Zr‐bearing steels. The ferrite transformation in steels with different Ti–Zr contents is observed using a high‐temperature confocal laser scanning microscope (HT‐CLSM). The average composition and size of inclusions and the information about the nucleation of acicular ferrite (AF) are analyzed using a scanning electron microscope. When the content of titanium in the steel increased from 70 to 370 ppm, the main composition in the inclusion transformed from Al2O3 to Ti2O3, the volume fraction of AF increased from 24.4% to 52.5%. The average content of ZrO2 in inclusions is 0%, 18.51%, and 90.39%, when the Zr content of steel is 0 80, and 140 ppm, the volume fraction of AF is 52.5%, 76.9%, and 56.8%. The relationship between the cosine of the contact angle at the inclusions‐ferrite interface and the diameter of inclusions is established based on experimental results, which is consistent with the results calculated based on the classic nucleation theory.

Gasification and structural behaviour of different carbon sources and resultant chars from rapid devolatilization for HIsarna alternative ironmaking process

To evaluate the potential of using renewable biomass in the novel HIsarna technology, reactivity of thermal coal (TC), charcoal (CC), Bana grass char (BGC) before and after rapid devolatilization at 1500 °C in a drop tube furnace (DTF) was investigated. Thermogravimetric (TG) was used for CO2 gasification study, and high temperature confocal scanning laser microscope (HT-CSLM), Brunauer-Emmett-Teller (BET) and scanning electron microscopy (SEM) were used to characterise the morphology of all three raw carbonaceous materials and their chars produced by rapid devolatilization. CC has fastest gasification reaction before and after rapid heat treatment, and BGC raw is more reactive than TC raw but BGC 1500 °C and TC 1500 °C have very similar gasification behaviour. The reactivity index of the rapidly devolatilized char is reduced to 84.21% (BGC), 92.11% (TC) and 94.23% (CC) compared to their raw materials. This shows that BGC is more severely affected by the rapid devolatilization, and this behaviour is likely to be governed by the high ash content which will melt and cause pore blockage during heat treatment. According to HT-CSLM results the average particle sizes decreased by 28%, 24% and 20 % for TC, CC and BGC respectively. While the SEM images shown that TC has gone through significant structural changes during the rapid devolatilization, but CC and BGC maintained their parent structural shapes. The BET results indicate that TC is non-porous, but both CC and BGC contain a large number of constricted micropores with significantly larger surface area.

In Situ Observations and Microstructure Evolution Behavior of Static Recrystallization of Microalloyed Continuous Casting Slabs in a Solidification End Reduction Process

Solidification end reduction is a novel technique that can effectively refine the microstructure and improve the homogeneity in continuously cast steel. Herein, the static recrystallization (SRX) behaviors and microstructure evolution of microalloyed continuous casting slabs during the heavy reduction (HR) process are simulated and analyzed by means of high‐temperature laser scanning confocal microscopy (HT‐LSCM). According to the statistical results of microstructure, the insulation temperature has a more significant effect on the SRX fraction and recrystallization grain size compared with the strain rate, initial austenite grain size, and prestrain, and a modified SRX kinetic model is proposed. Furthermore, a deforming microstructure is observed at different strains and holding times with electron backscatter diffraction (EBSD), and it is found that the reduction of high‐angle boundaries (HAGBs, θ &gt; 15°) of 25°–35° is related to strain‐induced boundary migration (SIBM). The stored deformation energy of HAGBs is higher than that of very low‐angle boundaries (VLAGBs, θ &lt; 5°) by the detailed misinterpretation profile analysis of the block and lath boundaries. Finally, the combination of in situ observation and EBSD analysis shows that the stored deformation energy provides the driving force for the SRX process, which, in turn, consumes dislocations to stabilize the microstructure.