Activation Energy For Recrystallization Research Articles

High temperature electropalsticity in Aermet100 steel by decoupling electron wind effect

Aermet100 ultra-high strength steel (UHSS) is one of the highest strength-plasticity-matched metallic materials. It is widely used in critical load-bearing components in aerospace and weaponry. Compared to traditional forging processes, electropulsing assisted forming technology significantly enhances manufacturing efficiency and forming limits. Particularly in the forming of hard-to-deform materials into complex structures, it demonstrates significant application potential. However, quantitative studies on the decoupling of electron wind effects during high-temperature deformation and their impact on microstructural evolution, deformation mechanisms, and mechanical properties remain few reported, resulting in limiting the ability to select optimal process parameters in electropulsing assisted forming technology to precisely control material structure and properties. In this paper, the impact of varying degrees of electron wind effects on flow stress through high-temperature compression tests was investigated. The evolution of the microstructure was analyzed in conjunction with the thermodynamic and kinetic mechanisms of recrystallization. Moreover, the hitherto unexplained relationship between the activation of slip systems and texture components in Aermet100 UHSS is examined. Results indicate that with the enhancement of the electron wind effect, the flow stress of Aermet100 UHSS is reduced by 59.4 %. The electron wind effect not only reduces the activation energy for recrystallization but also enhances vacancy concentration, dislocation climb diffusion flux, and driving force, thus promoting continuous dynamic recrystallization. Furthermore, as the intensity of the electron wind effect increases to 0.85 Ew and above, S and Brass textures are observed for the first time. It is notable that the Dillamore texture, Brass texture, and S texture respectively activate specific slip systems (1‾ 10)[11 1‾], (0 1‾1‾)[11 1‾] and (110)[1‾ 11‾] during the hot deformation process of Aermet100 UHSS. This investigation sheds new insight into tailoring high temperature electroplasticity by regulating electron wind effects.

The effect of pre-strain on textures, nano-twins and mechanical properties of a novel Nickel-based superalloy GH4251 with low stacking fault energy

By means of appropriate cold rolling pre-deformation, the tensile strength and plasticity of a novel polycrystalline precipitation-strengthened Nickel-based superalloy with low-stacking fault energy at 750 °C can be enhanced. The findings indicate that such pre-deformation leads to the emergence of microscopic substructures, including dislocations, anti-phase boundaries (APBs), stacking faults, and Lomer-Cottrell Locks (L-C locks). It is observed that the presence of these substructures is increased with the degree of pre-deformation. At the 15 % pre-deformation, a few deformation twins are detected near the grain boundaries, and their occurrence rises further in specimens subjected to 25 % pre-deformation. In addition, the nano-twins formation presents a strong correlation with the intensification of Brass-type textures. Notably, after the cold rolling pre-deformation, the alloy's yield strength as well as tensile strength at 750 °C is enhanced in contrast to those without pre-deformation, which is attributed to plentiful factors, such as low recovery and recrystallization activation energy, high-density nano-twins, grain refinement, and conducive crystallographic orientation for nano-twin mechanism activation caused by cold rolling pre-deformation. The specimen with 25 % pre-deformation exhibits relatively high tensile ductility. In this study, the relationships between pre-cold rolling deformation, microstructure, texture, and mechanical properties are comprehensively explored, indicating that the cold rolling pre-deformation holds promise for enhancing Nickel-based superalloys' strength and plasticity.

Influence of thermomechanical treatment on recrystallization and softening resistance of Cu−6.5Fe−0.3Mg alloy

The recrystallization and softening resistance of a Cu−6.5Fe−0.3Mg (mass fraction, %) alloy prepared by Process 1 (cold rolling heat treatment) and Process 2 (hot/cold rolling heat treatment) were studied using Vickers hardness tests, tensile tests, scanning electron microscopy and transmission electron microscopy. The softening temperature, hardness and tensile strength of the alloy prepared by Process 2 were 110 °C, HV 15 and 114 MPa higher, respectively, than those of the alloy prepared by Process 1 after aging at 300 °C. The recrystallization activation energy of the alloys prepared by Process 1 and Process 2 were 72.83 and 98.11 kJ/mol, respectively. The pinning effects of the precipitates of the two alloys on grain boundaries and dislocations were basically the same. The softening mechanism was mainly attributed to the loss of dislocation strengthening. The higher Fe fiber density inhibited the average free migration path of dislocations and grain boundary migration in the alloy, which was the main reason for higher softening temperature of the alloy prepared by Process 2.

Determination of Activation Energy For Static Re-Crystallization in Nb- Ti Low Carbon Micro Alloyed Steel

Data required for calculation the static re-crystallization kinetics have been evaluated from laboratory simulations. Series of two hit isothermal tests were conducted on high temperature torsion machine. These tests were conducted on four different temperatures and using inter-pass times between 0.5 and 5s with aim to investigate the influence of thermal activation on static re-crystallization. All tests were conducted on temperatures over TNR temperature, i.e. in temperature range in which all niobium is present only in solid solution. Method of evaluation of re-crystallization fraction was mechanical metallography, i.e. evaluation based on shape of each stress- strain curve. The fraction softening was calculated for all temperatures, together with avrami exponent, nA, and activation energy for re-crystallization, QSRX. Activation energy for static re-crystallization QSRX  281 KJ/mol and avrami exponent nA  1 determined in this work are in excellent agreement with previously reported data.

Unveiling the recrystallization mechanism and kinetics parameters in cold-rolled dual-phase stainless steel using differential scanning calorimetry

The present work aims to assess the Recrystallization mechanism and Kinetics parameters in Cold-Rolled Dual-Phase stainless steel. For this purpose, Differential Scanning Calorimetry was used over a range of 5–20 K/mn of heating rate, to identify the classical kinetic parameters such as recrystallization temperature, activation energy, and growth mechanism following 90 % reduction in thickness. The findings revealed that the recrystallization temperature increased with rising heating rates within the range [706.8–732] for the ferrite phase, as well as [1282.0–1360.3] K for the austenite phase. The estimated activation energies for ferrite and austenite recrystallization fell within the range of [207.2 ± 1.4–220.1 ± 2.5] kJ/mol and [220.2 ± 2.0–241.1 ± 4.0] kJ/mol, respectively. The Avrami parameter approached half-unity for both ferrite and austenite recrystallized phases for which results can be interpreted to be chiefly responsible for a general mechanism involving the growth of new grains with appreciable initial volume through a diffusion-controlled process.

Simultaneous enhancement of elevated temperature strength and ductility in additive-manufactured nickel-based superalloy via doping Y2O3 nanoparticles

In this work, we coated a layer of Y2O3 particles in Hastelloy X (HX) nickel-based superalloy powder by in situ chemical method and combined with laser powder bed fusion (LPBF) technology to develop a high-performance Y2O3-doping alloy, designated as Y-HX. The results show that the doping of Y2O3 particles prevents crack formation during the printing process and reduces solute segregation at cell and grain boundaries by increasing the viscosity of the molten pool. The doping of Y2O3 particles to the printed Y-HX alloy enhances grain boundary characteristics, transforming coarse sheet-like carbides into finely dispersed granular carbides at the boundaries during subsequent heat treatment. Additionally, doping with Y2O3 particles increases the recrystallization activation energy of the Y-HX alloy from 149.4 to 278.8 kJ mol–1. At 750 °C, the Y-HX alloy exhibits an ultimate tensile strength of 619 ± 2 MPa and an elongation of 52 % ± 2 %, along with an ultimate tensile strength of 325 ± 3 MPa and an elongation of 47 % ± 2 % at 900 °C. Our work provides a promising way to develop additive-manufactured superalloys with exceptional thermal stability and remarkable high-temperature mechanical properties.

Achieving ultrahigh strength and ductility via high-density nanoprecipitates triggering multiple deformation mechanisms in a dual-aging high-entropy alloy with precold deformation

How to achieve high-entropy alloys (HEAs) with ultrahigh strength and ductility is a challenging issue. Precipitation strengthening is one of the methods to significantly enhance strength, but unfortunately, ductility will be lost. To overcome the strength–ductility trade-off, the strategy of this study is to induce the formation of high-density nanoprecipitates through dual aging (DA), triggering multiple deformation mechanisms, to obtain HEAs with ultrahigh strength and ductility. First, the effect of precold deformation on precipitation behavior was studied using Ni35(CoFe)55V5Nb5 (at.%) HEA as the object. The results reveal that the activation energy of recrystallization is 112.2 kJ/mol. As the precold-deformation amount increases from 15 % to 65 %, the activation energy of precipitation gradually decreases from 178.8 to 159.7 kJ/mol. The precipitation time shortens, the size of the nanoprecipitate decreases, and the density increases. Subsequently, the thermal treatment parameters were optimized, and the DA process was customized based on the effect of precold deformation on precipitation behavior. High-density L12 nanoprecipitates (∼3.21 × 1025 m−3) were induced in the 65 % precold-deformed HEA, which led to the simultaneous formation of twins and stacking fault (SF) networks during deformation. The yield strength (YS), ultimate tensile strength, and ductility of the DA-HEA are ∼2.0 GPa, ∼2.2 GPa, and ∼12.3 %, respectively. Compared with the solid solution HEA, the YS of the DA-HEA increased by 1,657 MPa, possessing an astonishing increase of ∼440 %. The high YS stems from the precipitation strengthening contributed by the L12 nanoprecipitates and the dislocation strengthening contributed by precold deformation. The synergistically enhanced ductility stems from the high strain-hardening ability under the dual support of twinning-induced plasticity and SF-induced plasticity.

The impact of precipitation on recrystallization in a severely plastically deformed CoCrFeMnNi multi–principal element alloy

The present study investigated the rate-controlling mechanism for recrystallization kinetics in a severely plastically deformed (SPD) multi–principal element alloy. For this purpose, an equiatomic Cantor alloy (CoCrFeMnNi) was subjected to equal channel angular processing (ECAP) at room temperature and annealed at 773–973 K. The major recovery process was found to be concurrent recrystallization with precipitation. The recrystallization kinetics, investigated in the frame of the Johnson–Mehl–Avrami (JMAK) theory, gives a retarded recrystallization with a high recrystallization temperature of above 0.54Tm and an anomalous low JMAK exponent value of 1.1–1.8. The measured apparent activation energy for recrystallization exhibited a steady increase over the duration, with initial values of 220.8 ± 7.5 kJ/mol rising to 313.9 ± 23.8 kJ/mol towards the end. The systematic analysis leads to the conclusion that the rate-controlling mechanism for recrystallization in ECAP processed CoCrFeMnNi MPEA is the grain boundary migration-determined grain growth instead of nucleation. During this process, the Zener pinning effect exerted by precipitates from the concurrent precipitation with recrystallization plays the dominant role.

Microstructure evolution of the rolled tungsten during the current-assisted annealing treatment

Current-assisted annealing treatment (CAAT) is a promising method for adjusting the microstructure of metals. It was employed to heat treat the tungsten (W) with a rolling deformation of 90% to clarify its microstructure evolution under the action of current. The grain morphologies before and after heat treatment were observed by metallographic microscopy. Compared to traditional heat treatment, the CAATed W is easier to achieve full recrystallization with finer and more uniform grains. This indicates that the current increases the nucleation rate of recrystallization. The Johnson-Mehl-Avrami-Kolmogorov (JMAK) model was applied to describe the increase rate of recrystallization fraction. It can be calculated that the apparent activation energy of recrystallization under current is only 352.9 kJ/mol. Combined with electron backscatter diffraction (EBSD) characterization, the rolled W prefers to align along the 〈100〉 // ND orientation with the prolonging of current action time. In essence, the acceleration of recrystallization and the tendency of grain orientation are both related to the atomic migration enhanced by current. The electric current can generate an additional driving force for atomic migration, especially in regions with high electrical resistivity, where this driving force becomes more pronounced, leading to intensified atomic migration.

Effect of Zr on static recrystallization of deformed austenite and strain-induced precipitation in Ti microalloyed steel

The static recrystallization and strain-induced precipitation behavior of Ti and Ti-Zr low carbon microalloyed steels were studied through isothermal stress relaxation experiments at different deformation temperatures (875–1025 °C). The precipitation kinetic curves of microalloyed carbides were obtained, and the effect of Zr on the precipitation kinetics of microalloyed carbides was analyzed. Two static recrystallization kinetic models were established, and the activation energies for static recrystallization of Ti steel and Ti-Zr steel were calculated to be 312.44 and 246.59 kJ/mol, respectively. The results indicate that the addition of Zr lowers the nose point temperature of the precipitation–time–temperature curve, shortens the incubation period for the nucleation of precipitates, promotes the nucleation of strain-induced precipitates in Ti microalloyed steel, and reduces the coarsening rate of precipitates particles by an order of magnitude. In addition, the addition of Zr also advances the end time of static recrystallization of deformed austenite, inhibits the growth of static recrystallization austenite grains in Ti steel during the isothermal process, and makes the austenite grains finer and more uniform.

Effect of sigma (σ) phase precipitation on the recrystallization kinetics of AISI 904L superaustenitic stainless steel

Microstructural evolutions, σ-phase precipitation, and recrystallization kinetics of cold-rolled AISI 904L stainless steel during annealing were studied in the present work. The microstructure and hardness evolution were different in the temperature ranges of T < 950 °C (with σ-phase precipitation) and T ≥ 950 °C. The former range was associated with the fall of hardness due to recrystallization softening, followed by hardening due to the concurrent σ-phase precipitation; while the latter range was associated with the continuous fall of hardness. Using the Johnson–Mehl–Avrami–Kolmogorov (JMAK) analysis, the recrystallization activation energy in these ranges were respectively determined as 325 and 257 kJ/mol, where the higher activation energy in the former range was correlated to the retardation effect of the σ-phase. Via applying the Kissinger's equation to the differential scanning calorimetry (DSC) results, the activation energy of ∼332 kJ/mol was obtained, which was consistent with the precipitation of the σ-phase.

Research on the Recrystallization Process of the Ti-70 Titanium Alloy Sheet

As Ti-70 is a new type of marine titanium alloy, research on the recrystallization process of its sheet is necessary. This article studies the effects of different temperatures and times of annealing on the recrystallization process of 5.0 mm thick Ti-70 titanium alloy cold-rolled sheets by metallographic analyses and hardness tests. The results show that after 30 min of annealing at 620~700 °C, the recrystallization process was mostly complete, and uniform and equiaxed recrystallized grains could be obtained. The recrystallization process starts after 8 min of annealing at 700 °C, and after holding for 15~30 min, the recrystallization process is almost complete and the grain size is about 8.2 μm. The recrystallization activation energy of a Ti-70 titanium alloy cold-rolled sheet is Qr = 11.0645 × 104 J/mol. The ultimate tensile strength (Rm) can be controlled between 705 and 852 MPa, the yield strength (Rp0.2) can be controlled between approximately 623 and 793 MPa, and the elongation percentage (A) can be controlled between approximately 10.0 and 25.0% after rolling and heat treatment of Ti-70 alloy sheets.

Determination of Activation Energy for Static Recrystallization in Al-Mg-Si Alloys with Different Zr Contents

In this study, activation energies required for the static recrystallization behavior during the annealing process after cold deformation of Al-Mg-Si alloy to which zirconium was added in various proportions were investigated. Depending on the zirconium content, the activation energies of the alloys were found and compared both experimentally and by calculation. For this purpose, alloys containing 0.1, 0.2 and 0.3 wt-% Zr were cold rolled after taking into solution and quenching. And then, the alloys were annealed at 375 °C and 500 °C for different annealing times. After the alloys were prepared metallographically, their grain structures were examined microscopically. Depending on the temperature, recrystallization-% was found by image analysis and experimental recrystallization-% curves were drawn. The time taken for recrystallization-50% to experimentally find the activation energy required for recrystallization to occur was found from the curves. These values were replaced in the relevant formulations and the required activation energy was experimentally found from the slope of the Arrhenius equation and the ln t50% and 1/T graph. In order to find the recrystallization-% by calculation, the nucleation rate and growth rate of the new recrystallized grains were found by image analysis. By substituting these values in Johnson-Mehl-Avrami equation, the calculated recrystallization-% curves of the alloys were found. From here, using the relevant equations, Arrhenius equation was passed and the activation energy was calculated from the slope of ln k and 1/T graph. The results showed that the activation energy increased with the increase of the zirconium ratio, and even the most effective zirconium ratio was between 0.1-0.2% by weight in increasing the activation energy. Therefore, this ratio should be considered in processes where recrystallization, which also affects other properties of the alloy, is not desired.

Arrhenius constitutive model and dynamic recrystallization behavior of 18CrNiMo7-6 steel

In order to analyze the thermal deformation and dynamic recrystallization behavior of 18CrNiMo7-6 steel, the isothermal compression tests are carried out on Gleeble-3500 thermal simulator machine at deformation temperatures 973.15 K–1273.15 K with strain rates 0.001 s−1–1 s−1. Based on the true stress σ0.3, the Arrhenius constitutive models are constructed by using characterization parameters and physical base parameters, and the determination coefficients between the predicted values of the two models and the measured values are 0.98378 and 0.97613, respectively. The constitutive models of characterization parameters and physical base parameters considering strain effect are also constructed, and a comparative analysis is made. The results show that the predicted values of the characterization parameters constitutive model is closer to the measured values in the low strain region. After reaching the peak strain, the predicted values of the two constitutive models are close to the measured values, and both have high prediction accuracy. The dynamic recrystallization models are established to characterize the recrystallization behavior. The recrystallization activation energy of 18CrNiMo7-6 steel is 169.6793 kJ mol−1, the ratio of critical strain to peak strain is about 0.47074, and the ratio of critical stress to peak stress is about 0.94059. The activation energy of 50% dynamic recrystallization is 29.9844 kJ mol−1. The dynamic recrystallized grain size increases with increasing deformation temperature or decreasing strain rate, and the activation energy of grain growth is −49.9237 kJ mol−1.

Effect of Heat Treatment on Microstructure and Mechanical Behavior of Ultrafine-Grained Ti-2Fe-0.1B.

In the present study, a novel Ti-2Fe-0.1B alloy was processed using equal channel angular pressing (ECAP) via route Bc for four passes. The isochronal annealing of the ultrafine-grained (UFG) Ti-2Fe-0.1B alloy was conducted at various temperatures between 150 and 750 °C with holding times of 60 min. The isothermal annealing was performed at 350-750 °C with different holding times (15 min-150 min). The results indicated that no obvious changes in the microhardness of the UFG Ti-2Fe-0.1B alloy are observed when the annealing temperature (AT) is up to 450 °C. Compared to the UFG state, it was found that excellent strength (~768 MPa) and ductility (~16%) matching can be achieved for the UFG Ti-2Fe-0.1B alloy when annealed at 450 °C. The microstructure of the UFG Ti-2Fe-0.1B alloy before and after the various annealing treatments was characterized using electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). It was found that the average grain size remained at an ultrafine level (0.91-1.03 μm) when the annealing temperature was below 450 °C. The good thermal stability of the UFG Ti-2Fe-0.1B alloy could be ascribed to the pinning of the TiB needles and the segregation of the Fe solute atoms at the grain boundaries, which is of benefit for decreasing grain boundary energy and inhibiting the mobility of grain boundaries. For the UFG Ti-2Fe-0.1B alloy, a recrystallization activation energy with an average value of ~259.44 KJ/mol was analyzed using a differential scanning calorimeter (DSC). This is much higher than the lattice self-diffusion activation energy of pure titanium.

Constitutive Model and Cellular Automaton Simulation of the Dynamic Recrystallization of Railway EA4T‐Grade Steel

Herein, isothermal compression experiments are conducted on EA4T steel at 970–1170 °C, with strain rates of 0.01–1.0 s−1 and a strain of 0.2–0.8 s−1. Based on the experimental data, a high‐temperature constitutive model is developed for EA4T steel. The activation energy of dynamic recrystallization (DRX) is calculated to be 383 666 J mol−1, and the correlation coefficient and root mean square error between the results of the constitutive model and experimental results are 0.9943 and 4.6823, respectively. The average grain size for each deformation condition is determined using the linear‐intercept method. The grain growth model widely used in cellular automaton (CA) simulations is found unsuitable for EA4T steel. Therefore, a modified CA model of DRX behavior suitable for EA4T steel is developed. The nucleation rates and solute drag effect coefficients under different deformation conditions are determined. Furthermore, simulations are performed under other deformation conditions using the CA model. The simulated results for the average grain size, microstructure morphology, and DRX fraction agree well with the experimental results. The reason for the deviation between the observed and simulated DRX fractions is also explored.

Stimulating the inverse transformation of amorphous second-phase particles in irradiated Zr alloy to modulate the nanostructure

Amorphization of the second phase particles in irradiated zirconium alloys tends to lead to defect formation, radiation growth and corrosion resistance reduction, while conventional annealing requires higher temperature to promote amorphous crystallization transformation, which may reduce the performance of materials. Based on the difference of electrical properties between the second phase particles and the matrix, the pulsed electric current can induce the crystallization of amorphous second phase particles at a lower temperature by introducing additional electrical free energy, so as to achieve the microregion regulation of materials. The pulsed electric current effectively reduces the recrystallization activation energy of the second phase particles from 96 kJ/mol to 63.68 kJ/mol, thus lowering the recrystallization barrier to accelerate its process. The proposed pulsed electric current can rapidly reverse the crystal structure of amorphous second phase particles at lower temperatures, which provides a novel idea for adjusting the microstructure of metal materials.

Static Recrystallization Behavior of Low-Carbon Nb-V-Microalloyed Forging Steel

Static recrystallization is a method of tailoring the microstructure and mechanical properties of steels, which is important for microalloyed forging steels as the hot deformation process significantly affects their mechanical properties. In this paper, the static recrystallization behavior of a low-carbon Nb-V-microalloyed forging steel was investigated by double-pass hot compression tests at deformation temperature of 800–1100 °C and interruption time of 1–1000 s. The static recrystallization fractions were determined using the 2% offset method. The static recrystallization activation energy and the static recrystallization critical temperature (SRCT) of the experimental steel were determined. When the deformation temperature was higher than the SRCT, the recrystallization fraction curve conformed to the Avrami equation. When the deformation temperature was below the SRCT, the recrystallization curve appeared to plateau, which was caused by strain-induced precipitation. Before and after the plateau, the static recrystallization kinetics still obeyed the Avrami equation.

Transverse microstructural evolution and its cellular automata simulation during hot rolling of AZ31 alloy wide-width plate

The microstructure characteristics and transverse distribution laws during the hot flat rolling of 1500 mm wide AZ31 plate were studied in this paper. The microstructure morphology was analyzed experimentally, the thermal-mechanical coupling behavior was simulated, and the cellular automaton (CA) microscopic simulation model was established. A series of CA simulation functions and related material parameters were presented, which can accurately predict the microstructure evolution during rolling process and be verified through experimental results. The results showed that, the horizontal microstructure distribution of wide AZ31 plate was uneven significantly, which is characterized by a typical chain dynamic recrystallization mechanism and obvious shear bands structure at the transverse edge area. In particular, the average grain size (Dm) and dynamic recrystallization volume fraction (VDRX) showed significant differences along the transverse. The recrystallization activation energy (Qact) and hardening index parameters (θ0) suitable for the evolution of wide plate rolling to different areas are determined by using the reverse search method based on Dm index and VDRX index.The accuracy of CA model is verified by comparing the grain size dispersion and analyzing the relative error. Moreover, based on the CA model, the continuous and uninterrupted distribution characteristics of transverse microstructure of wide AZ31 plate after rolling were obtained. CA simulation results shows that from transverse center to edge area, the heterogeneity of microstructure is remarkable. The Dm and VDRX increase first and then decrease, and will turn in 1/4 width.

High thermal stability of nanocrystalline FeNi2CoMo0.2V0.5 high-entropy alloy by twin boundary and sluggish diffusion

A nanocrystalline (NC) face-centered cubic FeNi2CoMo0.2V0.5 high-entropy alloy was produced by high pressure torsion (HPT). The evolutions of microhardness and microstructure of the NC alloy during subsequent isochronal annealing were investigated systematically by electron back-scattering diffraction (EBSD) and high-resolution transmission electron microscopy (HRTEM). It was found that nano-grains and deformation nano-twin lamella were obtained at outer disk edge after HPT process with a hardness plateau of 450 HV. Isochronal annealing below 600 °C induced an evident hardening without precipitation effect, due to the annihilation of mobile dislocations and sustained deformation twin barriers. Evident recrystallization and grain growth of the NC FeNi2CoMo0.2V0.5 high-entropy alloy occurred during isochronal annealing at temperatures higher than 600 °C. The activation energies of recrystallization and grain growth of the NC FeNi2CoMo0.2V0.5 high-entropy alloy were calculated to be 350 kJ/mol and 272 kJ/mol, respectively, corresponding to a slow defects recovery process and a swift GB migration process. The high thermal stability of the NC FeNi2CoMo0.2V0.5 high-entropy was mainly caused by kinetic sluggish diffusion effect and deformation twin boundaries with thermodynamic low boundary energy, which retarded the movements of dislocations and grain boundary.