High Temperature Deformation Research Articles

Energy dissipation and notch sensitivity of mild steel at different strain rates and temperatures

Understanding of energy dissipation process of the selected material for a crashworthy structure is essential for its safety and reliability. Critical stress analysis for notched components of the structure is important to determine stress concentration factor. Commonly used mild steels are the primary choice of design engineers as the structural materials due to their good combination of mechanical properties, low cost and availability. Therefore, this paper presents the study of the flow behaviour of a mild steel with its energy dissipation capacity and notch sensitivity at strain rates 0.0001–0.1 s−1 and temperatures 25–500 °C under tensile, compressive and flexural loads. Several tests are conducted on electromechanical universal testing machine (Zwick/Roell, 250 kN) with the suitable fixtures. High temperature (300–500 °C; heating rate 8 °C/min, soaking time 15 min) deformation behaviour is studied and, the phenomenon of “blue brittle” is observed. Heat treatment (400–700 °C) effects on the steel behaviour are considered for heating rate 12 °C/min and soaking/holding time 1–3 h. Fractography analysis is done to know the nature of fracture surfaces. Influence of different notch profiles (C, U and V) on tensile behaviour of the steel is observed and, notch sensitivity ratio (NSR) is determined for their varying dimensions. It is found that the energy dissipation increases with increasing radius/angle in notched (C, U and V) specimens of the steel. Steel properties are found dependent on specimen geometry. Flexural/three-point bending behaviour (0.0001–0.01 s−1) is studied for 120–160 mm span lengths. Linear relationships of yield strength, ultimate strength and toughness/energy dissipation of the steel with logarithmic strain rate are presented. Finally, the Cowper-Symonds and Johnson-Cook material models are calibrated at different loading conditions.

Preparation, characterization, and properties of asphalt modified by surface-treated anhydrous calcium sulfate whiskers

In this study, anhydrous calcium sulfate whiskers (ACSW) were surface-treated with sodium carbonate and stearic acid to prepare inorganic–organic surface-co-treated ACSW modified asphalt. To investigate the mechanism, the co-treated ACSW were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), water contact angle (WCA), and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). Additionally, the rough surface of the calcium stearate was examined. The effects of the co-treated ACSW on asphalt binder properties were examined using conventional tests (penetration, ductility, softening point, and storage stability) and rheological tests, such as dynamic shear rheometer (DSR) and multiple stress creep recovery (MSCR) tests. The results indicated that 2–3% of the co-treated ACSW enhanced the high-temperature stability and deformation resistance properties of asphalt but weaken the low-temperature performance to a lesser extent. Microstructural analysis showed that the co-treated ACSW were physically modified with asphalt and uniformly distributed in the modified asphalt binder. This study provides a new concept for the ACSW surface treatment for practical applications in asphalt road pavement engineering in high-temperature regions.

Study on rheological and micro-structural properties of different modified asphalt by using organic and inorganic modifier

In order to evaluate the high and low temperature rheological properties of different modified asphalt, this paper prepared different types of modifiers and short-term aging modified asphalt (RTFOT), using dynamic shear rheometer (DSR) and bending beam rheological test (BBR) to compare and analyze the deformation resistance and stress sensitivity of different types (organic and inorganic) modified asphalt, determine its PG classification, and evaluate its fitting parameters with the help of Burgers model. The low-temperature mechanical properties of the fitting parameters were evaluated by the Burgers model; the chemical composition of different modified asphalts was analyzed by Fourier transform infrared spectroscopy (FTIR), and the microscopic state of the modified asphalts was observed by fluorescence microscopy. The results show that: with the increase of temperature, the high temperature deformation resistance of organic modified asphalt is better than that of inorganic modified asphalt, and PE modified asphalt is the best, and the low temperature performance of inorganic modified asphalt is poor, and the addition of SBS It will improve the low temperature crack resistance of asphalt. The road performance of different modified asphalts from strong to weak are PE modified asphalt, SBS modified asphalt, diatomite modified asphalt, montmorillonite modified asphalt. The research results have certain reference value for further research on different types (organic and inorganic) of modified asphalt.

Fold interference pattern and crustal decoupling in northern Tanzania

High-temperature granulite facies metamorphism and deformation evolved through Neoproterozoic tectonic processes in large parts of southeastern Africa. The Eastern Granulites of Tanzania, one example for these extreme conditions, show progressive decoupling between lower and middle crust together with progressive cooling and rheology stratification. Coupled deformation during earliest stages of deformation arises from extremely small viscosity contrast of all minerals and rocks at granulite facies metamorphic conditions around 850 °C. With cooling of the orogen rheology stratification increases and deformation decouples into horizontal stretching through gravity driven channel flow in the lower crust and thickening and horizontal west-east shortening in the middle/upper crust. As soon as a stiff and cold indenter, represented by external parts of the Archean Tanzania Craton (Western Granulites) enters the system, the indenter acts as lower crustal ramp along which deep crustal units are exhumed and displaced towards the foreland. During this orogenic period the crust was fully stratified and a second phase of decoupling, detachment over crustal scale ramp, occurs. Superposition with late orogenic north-south shortening structures resulted in type 1 fold interference pattern and formation a of dome-and-basin geometry in northeastern Tanzania. Structural modelling of fold superposition helps to explain the complex structural pattern and to predict sites of decollement horizons. By comparison with fold interference pattern exposed in southern Madagascar we define different types of dome-and-basin formation. Those with neglectable rheology contrast are viscosity determined where mixing of upper and lower crustal material is enabled by vertical flow folding. Those with strong viscosity contrast are mechanically determined where domes and basins are formed by changes in regional principal stress directions.

Design, fabrication, and magnetic properties of novel (Ni,Cr,Zr)-co-doped M-type barium ferrite ceramics

Multicomponent co-doping is an effective method to balance the counteracting magnetic properties of ferrite ceramics. In this work, novel (Ni,Cr,Zr)-co-doped M-type barium hexaferrites (BaFe12-3xNixCrxZrxO19, x = 0–0.8) were designed and synthesized by traditional solid-state reaction. Thermogravimetric analysis indicated that NiO would participate in the formation of secondary phase NiFe2O4 in the as-synthesized powder. Through traditional solid-state sintering, by using the synthesized pure-phase magnetic powders, almost full-dense ceramics were fabricated. Visual high-temperature deformation analysis revealed that there was no obvious difference in the sintering behavior and densification temperature of the ceramics with different compositional x, due to the low sintering activity of the as-synthesized magnetic powders. And X-ray diffraction analysis indicated that all the fabricated ceramics are of pure-phase M-type barium ferrite, and the lattice parameter c/a firstly increased as x raised up to 0.4 and then remained almost unchanged with further increased x, even if the lattice distortion became heavier. Microstructure examination revealed that the grain size monotonously decreased as the quantity of the substituent ions increased. The remnant magnetization and coercivity of the fabricated ceramics decreased monotonously as x increased, while the saturated magnetization could be maintained till the samples with x ≤ 0.4. Taking all the parameters into consideration, the samples with x = 0.4 might be a good candidate for transformer cores.

Effect of Sr addition on the high temperature deformation behavior and processing maps of Mg-7Sn alloy

The effect of strontium (Sr) addition (1 wt%) on the hot deformation behavior of Mg-7Sn (wt%) was investigated by performing high temperature compression tests in the temperature range of 300–450 °C and at strain rates of 0.05 s−1 – 5 s−1. The flow stress curves suggested the occurrence of dynamic recrystallization (DRX). The constitutive equation was developed using an Arrhenius-type hyperbolic sine equation. The addition of Sr to Mg-7Sn led to a decrease in the activation energy value, suggesting easy hot working as compared to Mg-7Sn alloy. The processing maps were further generated for both alloys at 0.2 strain (strain near peak stress). For both alloys, the high-efficiency domain appeared in the high temperature and high strain rate ranges. However, it was observed that the safe working region increased for Sr-added Mg-7Sn compared to Mg-7Sn alloy. The deformed microstructures from the safe region characterized using electron backscatter diffraction (EBSD) showed faster development of recrystallized grain in Mg-7Sn-1Sr alloy. Further, the EBSD maps depicted the occurrence of particle stimulated nucleation (PSN) in Mg-7Sn-1Sr alloy which was absent in Mg-7Sn alloy. The PSN occurrence with the addition of Sr is predicted to cause easy deformation and increase the recrystallization fraction in the Mg-7Sn-1Sr alloy. The unstable regions showed the presence of voids in both the alloys.

A new measure to enhance the heat-resistant (4TiC + 5AlN)/Al composite by multi-scale Fe/Mn enrichment effect

Developing high-strength Al-based alloys that can operate at 250 °C and above remains a challenge. In this study, a heat-resistant and high-strength (4TiC + 5AlN)/Al–Fe–Mn composite is designed using the liquid–solid reaction and hot extrusion. The strengthening phases, including sub-micron TiC, micron Al3(Fe, Mn), nano-sized AlN, and nano-sized Al3(Fe, Mn), in which the in–situ AlN particles are distributed in the matrix as networks, exhibit an attractive strengthening effect. Based on the results of electron backscatter diffraction, the extruded (4TiC + 5AlN)/Al–Fe–Mn composite prefers to form fiber texture in the longitudinal and cross-section:<111>Al//ED. And the average grain size of (4TiC + 5AlN)/Al–0.3Fe–0.1Mn composite is 0.69 µm. The ultimate tensile strength of the (4TiC + 5AlN)/Al–Fe–Mn composite is as high as 215 MPa at 350 °C. And the high-temperature elongation of the (4TiC + 5AlN)/Al–Fe–Mn composite is maintained while increasing the high-temperature strength. The improved performance of the (4TiC + 5AlN)/All–Fe–Mn is attributed to the synergistic effect of the multi-scale Al3(Fe, Mn) phases and particles. Furthermore, the formed micrometer Al3(Fe, Mn) phases are used to regulate the distribution of the TiC and AlN particles. The nano-Al3(Fe, Mn) dispersoids that precipitated during the homogenization can enhance the high-temperature deformation resistance of the matrix. In particular, the Fe and Mn atoms tend to aggregate at the TiC/Al interface, effectively modifying the interfaces between ex-situ TiC particles and the Al matrix. The modified interfaces of TiC/Al are beneficial to load transfer strengthening. The strengthening mechanisms of the (4TiC + 5AlN)/Al–Fe–Mn composite have been analyzed in detail, and the main strength–increasing mechanisms are calculated from the microstructural data. This work may provide an important approach to preparing heat-resistant Al matrix composites with strength-ductility matching.

Phase/grain boundary assisted-3D static globularization mechanism of TC17 alloy based on the microstructure reconstruction and in-situ TEM observation

Lamellar globularization in the dual-phase titanium alloy is the key to improving plasticity and strength. However, the mechanism has not been fully elucidated so far. In this work, the role of phase/grain boundary in the static globularization of TC17 alloy was systematically studied by setting different α phase content before annealing through low- and high-temperature deformation. Isothermal compression causes the parallel distribution and fragmentation of 3D α plates and few globular α particles are formed at a strain rate of 1 s–1. Post-deformation annealing promotes the static globularization of α phase while it is affected by initial α phase content. After 730 °C deformation, the development of α/α interface by absorbing dislocations promotes the formation of globular α grains based on the nucleation of separated α particles and pre-recovery α subgrain during subsequent annealing. The α/α/β and α/β/β triple junctions formed due to high α content with about 36% volume fraction are favorable for the further nucleation and growth of globular α grains by reducing interface energy, forming a 3D irregular α plate. Then nucleation and growth of the β phase dominate the microstructure evolution during subsequent annealing, resulting in the local dissolution of the plate and formation of α rods. After 850 °C deformation, the α phase tends to nucleate at the β/β/β triple junctions and grow into a lamellar shape along the high energy β/β grain boundary due to low α content with about 7% volume fraction. The α nucleation that maintains the Burgers orientation relationship (BOR) with the surrounding β phase grows along the habit plane and thickens slowly, resulting in the formation of a precipitated α plate with a flat surface and the suppression of static globularization. The comprehensive investigation of lamellar globularization provides guidance for optimizing the 3D microstructure and properties of dual-phase titanium alloy.

Strain rate sensitivity of low-temperature superplastic cold-rolled medium Mn steel with ultrafine equiaxed dual-phase microstructure

This study reports the evolution of strain rate sensitivity (SRS) a novel 3.6Al Medium Mn steel (MMS) with an ultrafine equiaxed dual-phase structure. By varying temperature and strain rate, a new bidirectional reciprocating strain rate jump experiment was conducted to evaluate the effect of strain rate on the SRS index m. Tensile tests were conducted at high-temperature deformation to obtain the maximum m-value, and microstructure were characterized. The results demonstrate that at temperatures ranging from 700 °C to 750 °C and strain rates from 2.5 × 10−4 to 1.6 × 10−2 s−1, the m-value decreases monotonously with increasing strain rate, and the decreasing trend slows down. During high-temperature deformation, the m-value is more sensitive to changes in strain rate. At 700 °C, the grain refinement increases the m-value with the increase in strain. Interestingly, MMS exhibited new γ fiber and brass texture during deformation at 750 °C, with a larger m-value and better superplasticity (∼1295%).

Flow behavior and dynamic transformation of titanium alloy Ti62A during deformation at different temperatures and strain rates

The effect of deformation temperature and strain rate on the hot deformation behavior and dual-phase microstructure evolution of the titanium alloy Ti62A was examined using electron backscatter diffraction. In general, the activation energy of Ti62A during steady-state deformation in the (α + β) phase is 295 kJ mol−1. The primary recovery mechanisms of the β phase during hot deformation are dynamic recovery and dynamic recrystallization (DRX). Moreover, discontinuous DRX occurs at low temperatures and high strain rates, whereas continuous DRX occurs at high temperatures and low strain rates. Furthermore, high strain rates in the (α + β) phase and high deformation temperatures are advantageous to dynamic phase changes during dynamic transformation (DT). The β phase penetrates the lamellar α s phase, causing fragmentation and spheroidization of the α s phase. Finally, DT begins more easily in the fine α s phase than in the coarse α p phase.

A new high-pressure high-temperature deformation apparatus to study the brittle to ductile transition in rocks

Understanding the micro-mechanisms underlying the localized–ductile transition (LDT) as well as the brittle–plastic transition (BPT) has become crucial for our wider understanding of crustal processes and seismicity. Given how difficult in situ observations of these transitions are to perform, laboratory experiments might be our only way to investigate the processes active under these conditions (high T and high P). Here, we present Triaxial AppaRatus for GEoThermal energy, a new gas-based triaxial apparatus located at EPFL in Switzerland that was specifically designed to operate under conditions where both the LDT and BPT can occur in geomaterials. We show that the machine is capable of deforming rock samples at confining pressures of up to 400 MPa, temperatures of up to 800 °C, and pore pressures (liquid or gas) of up to 300 MPa while keeping the temperature gradient along samples of 40 mm in length and 20 mm in diameter minimal (less than 30 at 700 °C). Most importantly, the maximum load is 1000 kN (stresses as high as 2.2 GPa on 24 mm samples and 3 GPa on 20 mm samples), allowing for the deformation of very competent rock samples. Moreover, during deformation, the pair of syringe pore pressure pumps allow for continuous permeability or dilatancy recording. We benchmarked our machine against existing data in the literature and show that it accurately and precisely records stress, strain, permeability, pressure, and temperature.

Rheological properties of composite DTDM/DOP/SBS modified asphalt and its effect on high and low temperature performance

To investigate the effect of crosslinker (DTDM) and plasticizer (DOP) on the rheological properties of SBS modified asphalt at high and low temperatures. In this study, the composite DTDM/DOP/SBS modified asphalt was subjected to infrared spectroscopy, dynamic shear rheology, and low-temperature bending beam rheology experiments. Analysis of microscopic properties and high and low temperature rheological properties of composite DTDM/DOP/SBS modified asphalt. The findings of the tests suggest that the cross-linking agent (DTDM) and plasticizer (DOP) have a better chemical response with SBS modified asphalt. It may significantly increase SBS modified asphalt's high-temperature deformation resistance, elastic recovery capacity, low-temperature fracture resistance, and aging resistance. The research findings have theoretical and practical significance for enhancing asphalt high and low temperature performance.

Dynamic Constitutive Relationship of Mg–Gd–Y–Zr–Ag Alloy during High Temperature Deformation Process

The thermal deformation behavior of the Mg-Gd-Y-Zr-Ag alloy was studied by isothermal hot compression tests at high temperatures. The flow stress increased with increased strain rates and decreased temperatures, first increasing and finally remaining stable with increased strain. A hot processing map was built. Using the processing map and microstructural analysis, the temperature should remain at 673-773 K for this alloy to ensure the deformation quality. The primary softening mechanism is discontinuous dynamic recrystallization (DDRX). Rising temperatures and declining strain rates facilitated the emergence and growth of Dynamic recrystallization (DRX) grains. An original JC (O-JC) model and a modified JC (M-JC) model were established. The M-JC model indicated a better prediction than the O-JC model. Still, it was deficient in predicting flow stresses with insufficient coupling effects. Hence, based on the M-JC model, a newly modified JC (NM-JC) model, which further enhances the interaction between strain and strain rate as well as strain and temperature, is proposed. Its projected values can better align with the tested values.

The Microstructure Evolution and Dynamic Recrystallization Mechanism of Cu-1.1–Ni-0.7–Co-0.45–Si-0.3Cr Alloys during High-Temperature Deformation

Copper alloys with a combination of good electrical conductivity and mechanical properties are widely used in automotive electronics, large-scale integrated circuits, and other fields. In this study, a new type of Cu–Ni–Si alloy with added trace elements of Co and Cr was fabricated. Hot compression tests of this alloy at different temperatures and strain rates were conducted using a Gleeble-1500D simulator. Then, the microstructure transformation and precipitation behaviors of the Cu-1.1–Ni-0.7–Co-0.45–Si-0.3Cr alloy were studied during a hot deformation process. The results show that the hot deformation behavior of the Cu-1.1–Ni-0.7–Co-0.45–Si-0.3Cr alloy includes continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX). The intensity of the texture in the microstructure is decreased, and the randomness of the texture in the microstructure is increased together with the recrystallization progress. The degree of recrystallization of the new Cu-1.1–Ni-0.7–Co-0.45–Si-0.3Cr alloy is increased when the hot deformation temperature rises. Additionally, the results indicate that there are two types of precipitates which are formed in the alloy during the hot deformation process. These two precipitates can pin dislocations and grain boundaries, and therefore, they significantly improve the hot compression resistance of the Cu-1.1–Ni-0.7–Co-0.45–Si-0.3Cr alloy.

In situ observation of deformation and failure behavior in the burn-through instability zone of in-service welding

Based on the in-situ high-temperature SEM and laser scanning confocal microscope (LSCM), the high-temperature plastic deformation and failure behavior of X65 pipeline steel at 1000℃ and 1200℃ were studied in this paper, and the strain evolution behavior in this process was analyzed by DIC technology. In this study, the precipitation and dissolution of carbide at the austenite grain boundary were observed during the in situ heating process. The external load showed a great effect on the growth of the grains, and the grains grew rapidly by swallowing each other. The grain size, material performance, and misorientation played an important role during the deformation and crack evolution. At high temperatures, cracks were mainly initiated and propagated in the position with a large plastic strain. The strain concentration showed a significant effect on crack initiation.

Interpolation and Extrapolation Performance Measurement of Analytical and ANN-Based Flow Laws for Hot Deformation Behavior of Medium Carbon Steel

In the present work, a critical analysis of the most-commonly used analytical models and recently introduced ANN-based models was performed to evaluate their predictive accuracy within and outside the experimental interval used to generate them. The high-temperature deformation behavior of a medium carbon steel was studied over a wide range of strains, strain rates, and temperatures using hot compression tests on a Gleeble-3800. The experimental flow curves were modeled using the Johnson–Cook, Modified-Zerilli–Armstrong, Hansel–Spittel, Arrhenius, and PTM models, as well as an ANN model. The mean absolute relative error and root-mean-squared error values were used to quantify the predictive accuracy of the models analyzed. The results indicated that the Johnson–Cook and Modified-Zerilli–Armstrong models had a significant error, while the Hansel–Spittel, PTM, and Arrhenius models were able to predict the behavior of this alloy. The ANN model showed excellent agreement between the predicted and experimental flow curves, with an error of less than 0.62%. To validate the performance, the ability to interpolate and extrapolate the experimental data was also tested. The Hansel–Spittel, PTM, and Arrhenius models showed good interpolation and extrapolation capabilities. However, the ANN model was the most-powerful of all the models.

Hot Deformation Behaviour of Additively Manufactured 18Ni-300 Maraging Steel

In this article, hot compression tests on the additively produced 18Ni-300 maraging steel 18Ni-300 were carried out on the Gleeble thermomechanical simulator in a wide temperature range (900-1200 °C) and at strain rates of 0.001 10 s-1. The samples were microstructurally analysed by light microscopy and scanning electron microscopy with electron backscatter diffraction (EBSD). This showed that dynamic recrystallization (DRX) was predominant in the samples tested at high strain rates and high deformation temperatures. In contrast, dynamic recovery (DRV) dominated at lower deformation temperatures and strain rates. Subsequently, the material constants were evaluated in a constitutive relationship using the experimental flow stress data. The results confirmed that the specimens are well hot workable and, compared with the literature data, have similar activation energy for hot working as the conventionally fabricated specimens. The findings presented in this research article can be used to develop novel hybrid postprocessing technologies that enable single-stage net shape forging/forming of AM maraging steel parts at reduced forming forces and with improved density and mechanical properties.

Effect of Al Concentration on Basal Texture Formation Behavior of AZ-Series Magnesium Alloys during High-Temperature Deformation

Magnesium and its alloys have been restricted in their industrial applications due to problems related to their formability. To overcome this issue, controlling the crystallographic texture is important, and the texture formation mechanism should be investigated in relation to factors including deformation conditions and solute atoms. In particular, the effects of solute atoms on the texture formation behavior should be further analyzed because they can considerably affect the deformation behavior. Thus, in this study, to clarify the effect of aluminum concentration on the texture formation behavior and microstructure, high-temperature uniaxial compression tests were conducted on three types of AZ-series magnesium alloys (AZ31, AZ61, and AZ91). Compression was conducted at 673 K and 723 K, with strain rates of 0.05 s-1 and 0.005 s-1, up to a true strain of -1.0. Cylindrical specimens were prepared from a rolled plate that had a (0001) basal texture and was compressed parallel to the c-axis of the grains. Consequently, work softening and fiber texture formation were observed in all the specimens. During the deformation, the development of grain boundaries, which is a typical characteristic of continuous dynamic recrystallization (CDRX), was observed, and the (0001) texture was highly developed with increasing Al content. Although each alloy was associated with the same deformation conditions and mechanisms, the AZ31 alloy exhibited a non-basal texture component. The stacking fault energy contributed to the generation of slip systems and gliding, and it was seen as the main reason for texture variation.

Enhanced strength and plasticity in a Nb2MoWC0.5 alloy via eutectic dilute carbide

Refractory niobium alloys are widely used in aero-engine combustion chambers and rocket propulsion systems. Conventional Nb-based alloys often suffer from insufficient high-temperature strengths or poor room-temperature plasticity. Here we report a strategy to develop a novel Nb2MoWC0.5 niobium alloy with a good strength-plasticity synergy by introducing eutectic NbC carbide. Microstructure characterization reveals that the as-prepared alloy exhibits a hypoeutectic microstructure, in which low-energy eutectic interface remains stable under high-temperature compression up to 1473 K. The stable low-energy metal-carbide interface enables not only a superior high-temperature strength (>1 GPa at 1473 K and 0.61 GPa at 1673 K) but also possesses good room-temperature plasticity (a true plastic strain of 16%) via microcrack tip blunting. The dilute NbC carbide with alloying elements has low stacking fault energy and improved high-temperature plastic deformation. This strategy provides theoretical guidance for designing next-generation high-performance high-temperature alloys to bypass the limitation of alloying elements in conventional refractory alloys.

Special deformation mechanisms dominated by grain boundary sliding of extrusion–refined Ti–22Al–25Nb alloy during compression in single BCC phase field

The deformation behavior of Ti–22Al–25Nb alloys with refined initial grain size was investigated under isothermal uniaxial compression in the BCC (B2) single-phase field, where a high-temperature extrusion process was used to produce the test materials with finer initial grains. As compressed at low to moderate strain rates, the present material exhibits significant continuous flow softening. To study the deformation and softening mechanisms during the compression, the samples' microstructures were examined using EBSD. The analysis shows that this alloy has a considerable grain boundary sliding (GBS) mechanism in addition to the conventional mechanisms of dynamic recovery (DRV), dynamic recrystallization (DRX), and texture softening. For the first time, this study offers direct evidence of the presence of GBS in current alloys. And the dominant role of GBS in high-temperature deformation and softening of current alloys was identified by comparing the impacts of various mechanisms on the dislocation density distribution. Besides, the impact of GBS on texture evolution was also discussed.