Work-hardening Rate Research Articles

Simultaneous increase of ultimate tensile strength and uniform elongation of 30Si2MnCrMoVE ultra-high strength steel by hot deformation direct quenching and partitioning

In order to further improve the combination of strength and ductility for 30Si2MnCrMoVE ultra-high strength steel (UHSS), a thermomechanical treatment, named deformation direct quenching and partitioning (DQ&P), was carried out on it. The microstructure evolutions and mechanical properties of 30Si2MnCrMoVE UHSS treated by DQ&P were compared with those treated by conventional off-line quenching and tempering (Q&T) through various microscopic characterization methods and uniaxial tensile tests. Moreover, the effects of austempering temperature on the microstructure evolutions and mechanical properties of the studied steel after DQ&P process were also investigated. The results show that the DQ&P samples, although lower or slightly lower yield strength, possess significantly higher ultimate tensile strength due to higher work-hardening rate caused by high density dislocations and fine dispersed carbides. Moreover, DQ&P310 sample exhibit apparently higher uniform elongation than Q&T sample despite of comparable content of retained austenite due to more prone to transformation induced plasticity (TRIP) effect. The DQ&P process can increase the ultimate tensile strength by 267 MPã423 MPa and the uniform elongation by 78%∼85%, respectively, as compared to Q&T process, which indicates that DQ&P process may be a promising thermomechanical treatment method to improve the comprehensive mechanical properties of the studied steel. The strengths and elongations of DQ&P samples do not vary monotonously with the increase of austempering temperature, which are both closely related to the content of retained austenite.

Effects of grain size and strain rate on the low-temperature tensile properties of ferrite-austenite duplex stainless steel

The effects of grain size and strain rate on the low-temperature tensile properties of ferrite-austenite duplex stainless steel were investigated. The coarse- and fine-grain specimens exhibited a grain size of approximately 20 and 8 μm, respectively. At 77 K, the fine-grain specimen exhibited a higher strength and elongation than the coarse-grain specimen. The work-hardening rate at 77 K in both specimens leveled off or increased slightly at late stage of deformation although the work-hardening rate was lower than the true stress. This characteristic work-hardening behavior is caused by the deformation-induced martensitic transformation of metastable austenite. Grain refinement stabilized austenite phase and enhanced the elongation of the material, resulting in the better low-temperature tensile properties of fine grain. The elongation decreased remarkably with an increasing strain rate at 77 K independent of grain size. The characteristic work-hardening was not detected at a high strain rate, indicating that the deformation-induced martensitic transformation did not occur. The strain rate affects the frequency of deformation-induced martensitic transformation, resulting in a change in elongation. Grain refinement effectively improves the low-temperature tensile properties of duplex stainless steels; however, these properties are strongly influenced by the strain rate, where a high strain rate causes a low elongation.

Characterization of hot deformation and microstructure evolution of a new metastable β titanium alloy

The hot deformation characteristics of as-forged Ti−3.5Al−5Mo−6V−3Cr−2Sn−0.5Fe−0.1B−0.1C alloy within a temperature range from 750 to 910 °C and a strain rate range from 0.001 to 1 s−1 were investigated by hot compression tests. The stress−strain curves show that the flow stress decreases with the increase of temperature and the decrease of strain rate. The microstructure is sensitive to deformation parameters. The dynamic recrystallization (DRX) grains appear while the temperature reaches 790 °C at a constant strain rate of 0.001 s−1 and strain rate is not higher than 0.1 s−1 at a constant temperature of 910 °C. The work-hardening rate θ is calculated and it is found that DRX prefers to happen at high temperature and low strain rate. The constitutive equation and processing map were obtained. The average activation energy of the alloy is 242.78 kJ/mol and there are few unstable regions on the processing map, which indicates excellent hot workability. At the strain rate of 0.1 s−1, the stress−strain curves show an abnormal shape where there are two stress peaks simultaneously. This can be attributed to the alternation of hardening effect, which results from the continuous dynamic recrystallization (CDRX) and the rotation of DRX grains, and dynamic softening mechanism.

Effect of Al Layer Thickness on the Bonding and Mechanical Behavior of a Mg-(Al-)Ti Laminated Sheet Prepared by Hot-Rolling after Differential Preheating Treatment.

Mg-(Al-)Ti laminated sheets with large bonding interfaces were prepared by a differential temperature hot-rolling process, in which the preheating treatment of Ti was 25–100 °C higher than that of Mg. The rolled sheets contained different Al layer thicknesses (≤0.05 mm), and the thickness of the diffused region at the interface of 3–7 μm was formed by rolling at 175 °C. The interfaces were the solid-solution regions of Mg(Al) and Ti(Al), and no intermetallic compounds were generated during both the rolling process and annealing treatment. The hardness of the interfaces was 16–30% greater than that of the Mg matrix and Ti matrix. The results of mechanical tests displayed that the Mg-(Al-)Ti sheets exhibited higher strength and elastic modulus compared to those of the rolled AZ31B sheet. Their UTS and YTS were about 223–460 MPa and 303–442 MPa, respectively, with an elongation of 0.04–0.17 and high elastic modulus of 52–68 GPa. The Mg-Ti (containing about 62 at.% Mg) rolled sheet exhibited the most excellent strength. The UTS and YTS were about 460 MPa and 442 MPa, with an elongation of 0.04 and elastic modulus of 61.5 GPa. Additionally, Mg-Ti sheets with thin Ti thickness possessed a higher work-hardening rate (n), as well as hardening rate, than the rolled Mg-Al-Ti sheets. This is because fractured Ti pieces around the interfaces have a significant strengthening effect. This study provides a simple method for fabricating Mg-(Al-)Ti sheets with high elastic modulus.

Unveiling the origins of work-hardening enhancement and mechanical instability in laser shock peened titanium

Laser shock-peening (LSP) produces complex gradients in microstructures and residual stresses, which enables fabrication of metallic engineering components with superior mechanical properties. Here we use non-destructive and spatially resolved high-energy X-ray diffraction (HE-XRD) to investigate the influences of LSP on microstructure, surface topography, and residual stress for high purity titanium plates. LSP is found to produce large compressive in-plane residual stresses near the peened surface which monotonically decay to zero about 2.5 mm below the surface. These properties were also tracked during in-situ tensile loading, allowing stress partitioning and work-hardening rates to be measured as a function of depth. The surface region is found to have the highest work-hardening rate and remain mechanically stable up to sample failure. In addition, a crystal rigid rotation along a transversal axis of about 27° was observed at large applied strain near the surface region, which is attributed to the formation of denser dispersed shear bands. Furthermore, a sudden drop in tensile stress was observed at a depth of ∼160 µm from the LSP surface, indicating the formation of a localized mechanical instability zone (LMIZ). The origin of this LMIZ could be attributed to the increase in shear stress induced by a load transfer from LSP surface due to the formation of denser dispersed shear bands. These observations indicate a localized transition in deformation behavior has occurred from dispersed shear banding to LMIZ and homogeneous deformation.

Visualization of strain distribution around fatigue crack developed by low cycle fatigue test in high-strength steels using digital image correlation method for replica films

Strain distributions around the fatigue crack during the low cycle fatigue of high-strength ferrite + martensite dual-phase (DP) and tempered martensite (Mt) steels were visualized during cycles from the initial state to the crack initiation and crack propagation using a digital image correlation analysis applied to replica films. The replica film successfully transcribed the microstructure on the specimen surface. Although both the DP and Mt. steels exhibited a high tensile strength, the work-hardening rate of the DP steel was higher than that of Mt. steel. Although the numbers of cycles to failure (Nf) in the DP and Mt. steels were almost the same at the total strain amplitudes (εt) of 0.005–0.008 and 0.02–0.03, the Nf in the DP steel was higher than that in the Mt. steel at the εt of 0.008–0.02. The cracks were generated and propagated along the high-tensile-strain regions in both steels and were initiated when the accumulated strain along the loading direction exceeded a critical value regardless of the value of εt or the steel applied. The increment of the accumulated strain in the Mt. steel was higher than that of the DP steel at the εt of 0.01, whereas it was almost the same between those at the εt of 0.03. The inhomogeneity of the strain distribution, which was quantitatively evaluated from the histogram of the strain distribution, increased as the number of fatigue cycles increased. The strain was rather inhomogeneously introduced in the Mt. steel in comparison to the DP steel at the εt of 0.01, whereas almost no difference in the inhomogeneity of the strain distribution was detected between the steels at the εt of 0.03. Thus, the inhomogeneous strain distribution may promote crack initiation and propagation, resulting in a low Nf at the εt of 0.008–0.02 in Mt. steel.

Effect of Intercritical Annealing Parameters and Starting Microstructure on the Microstructural Evolution and Mechanical Properties of a Medium-Mn Third Generation Advanced High Strength Steel

A prototype medium-Mn TRIP steel (0.2 C–6 Mn–1.7 Si–0.4 Al–0.5 Cr (wt %)) with a cold-rolled tempered martensite (CR) and martensitic (M) starting microstructures was subjected to continuous galvanizing line (CGL) compatible heat treatments. It was found that the M starting microstructures achieved greater than 0.30 volume fraction of retained austenite and target 3G properties (UTS × TE ≥ 24,000 MPa%) using an intercritical annealing temperature (IAT) of 675 °C with an IA holding time of 60–360 s, whereas the CR microstructure required an IAT of 710 °C and annealing times of 360 s or greater to achieve comparable fractions of retained austenite and target 3G properties. This was attributed to the rapid austenite reversion kinetics for the M starting microstructures and rapid C partitioning from the C supersaturated martensite, providing chemical and mechanical stability to the retained austenite, thereby allowing for a gradual deformation-induced transformation of retained austenite to martensite—the TRIP effect—and the formation of nano-scale planar faults in the retained austenite (TWIP effect), such that a high work-hardening rate was maintained to elongation of greater than 0.20. Overall, it was concluded that the prototype steel with the M starting microstructure is a promising candidate for CGL processing for 3G AHSS properties.

Microstructural evolution and its effect on the mechanical properties of Cu–Ag microcomposites

Abstract The microstructure and the mechanical properties of Cu– Ag alloys with 7 and 24 wt.% Ag are investigated. The microstructure of the alloys is mostly determined by the silver content. That of Cu-24 wt.% Ag alloys consists of a Cu-rich solid solution and the eutectic. Otherwise, the microstructure of Cu-7 wt.% Ag alloys consists of primarily solidified dendrites of a Cu-rich solid solution and small Ag-rich particles. The composition strongly influences the work-hardening rate. In order to achieve an ultimate tensile strength of 1 GPa, a logarithmic cold-deformation strain, η, of about 3.7 is required (η = ln A 0/A) for the 7 wt.% Ag alloy, whereas for Cu-24 wt.% Ag alloys η = 3.1 is sufficient. In as-cast alloys with 7 wt.% Ag a strong segregation is observed, which, consequently, leads to a strong decrease of the age-hardening effect. Therefore, the Cu-7 wt.% Ag alloy has to be homogenised before aging. The application of Cu–Ag alloys with a Ag-content below 8 wt.%, i. e. an the maximum solubility at the eutectic temperature, bears mainly two advantages: (i) less addiction to shear-band formation, and (ii) a higher electrical conductivity in comparison to equivalently treated Ag-rich alloys due to the small Ag content.

Heat treatment effects on the hydrogen embrittlement of Ti6Al4V fabricated by laser beam powder bed fusion

Hydrogen embrittlement (HE) behavior of Ti6Al4V produced by laser beam powder bed fusion (PBF-LB) was investigated via tensile tests with/without electrochemical H-charging, and the heat treatment (HT, 950 °C for 2 h) effects on HE mechanisms were also explored. Decreased resistance against HE after long-term H-charging is verified for the HT PBF-LB Ti6Al4V and this phenomenon is not obvious for the as-built (AS) PBF-LB counterparts. To understand this observation, we carried out microstructural characterization experiments including backscattered electron (BSE) image, electron backscatter diffraction (EBSD), transmission electron microscope (TEM), and hydrogen analyses based on X-ray diffraction (XRD) and thermal desorption spectrometry (TDS). These results and others reveal that the β phase introduced by the HT process attracts more hydrogen ingress compared with the full acicular α΄ martensitic phase in the AS PBF-LB parts. The lattice expansion of the hydrogenated β phase compels a localized stress field near the phase boundary, leading to an increased work-hardening rate under H-charging for the HT PBF-LB Ti6Al4V. Consequently, brittle titanium hydrides occur along with the α/β interfaces after H-charging, and the micro-voids preferentially initiate therein and coalesce to micro-cracks under plastic deformation. Therefore, a larger ductility loss is verified for the HT PBF-LB Ti6Al4V compared with the AS PBF-LB counterparts under the same H-charging condition.

Effects of short-range ordering and stacking fault energy on tensile behavior of nitrogen-containing austenitic stainless steels

The tensile behavior of austenitic stainless steels with different concentration of nitrogen was studied by analyzing deformation microstructure and calculating short-range ordering (SRO) as well as stacking fault energy (SFE). Increasing nitrogen concentration increased SFE and SRO, which affected the tensile behavior. From the early to intermediate deformation stages, the nitrogen addition induced slip planarity and the delay of dynamic recovery, which were brought by the increase of SRO. As a result, work hardening rate (WHR) rose with the nitrogen content at the end of the intermediate deformation stage. On the other hand, the SFE effect was noticeable at higher strain levels. With increasing nitrogen concentration, the formation of slip lines was suppressed and dynamic recovery was promoted. Hence, the reduction in WHR was accelerated with the nitrogen addition. When the overall dynamic recovery behavior was assessed with dislocation-density based constitutive modeling, it was found to depend mainly on SRO rather than on SFE. Therefore, the alloy with higher nitrogen content could achieve higher dislocation density and flow stress.

Heterogeneous evolution of lattice defects leading to high strength and high ductility in harmonic structure materials through atomic and dislocation simulations

Core–shell harmonic structure materials, in which coarse grains (core regions) are surrounded by many fine grains (shell region), have excellent mechanical properties, particularly, the coexistence of high strength and ductility. We use atomic and dislocation simulations to investigate the mechanism of the excellent mechanical properties. The harmonic structures are modeled simply while maintaining the three main characteristics of harmonic structure materials: heterogeneous distributed strength, interfaces between the core and shell regions, and shell region network. Based on the synergistic effect of the coexistence of core and shell regions, which is caused by the heterogeneous evolution of lattice defects near the core–shell interface as obtained in atomic and dislocation simulations, a possible mechanism providing high strength and ductility of the harmonic structure materials is discussed. Plastic deformation starts from the core regions with lower strength and progresses to the shell region with higher strength. The core–shell interfaces act as a strong barrier for the plastic deformation propagation from the core to shell regions because of the back stress caused by the transmitted dislocations in the shell regions, which increase the dislocation density of the core regions in contact with the interface, resulting in increased strength and work-hardening rate in the core regions. The former contributes to the high strength of the harmonic structure materials and the latter can suppress the plastic instability of the shell regions, resulting in high ductility of the harmonic structure materials.

Deformation behaviour of ultrafine-grained magnesium with 3 vol.% graphite

Abstract Magnesium micropowder was mixed and ball-milled with 3 vol.% graphite powder. The Mg + Graphite composite was deformed in compression at temperatures between room temperature and 300 °C at a constant crosshead speed, giving an initial strain rate between 1.4 · 10 –5 and 1.4 · 10– 3 s –1. The yield stress of the composite is higher than that of unreinforced magnesium prepared with the same technology. The yield stress and the maximum stress decrease rapidly with increasing temperature. At temperatures higher than room temperature, the true stress– true strain curves exhibit a work-hardening rate close to zero, which indicates a dynamic equilibrium between hardening and softening. Double cross-slip of screw components of c + a dislocations is considered as the main recovery mechanism.

Effect of Shear Direction on Work-Hardening Evolution of AISI 409 Steel Under Rolling/Shearing Loading

The mechanical behavior of metallic materials depends on several variables, such as the material structural characteristics, the process parameters, the temperature, the strain rate and the anisotropy features due to strain paths in different metal forming operations. Considering the last one, the effect of shear direction loading on the work-hardening after the rolling/shearing loading of a ferritic stainless steel, AISI 409, was investigated in this work. The annealed AISI 409 sheets were predeformed by cold rolling up 0.19 effective strain and then sheared at three different directions: at 0°, 45° and 90° from the original rolling direction. The samples were characterized through tensile, shear and Vickers microhardness tests while the study of crystallographic texture was performed using the electron backscatter diffraction (EBSD) technique. The work-hardening behaviour of the material was analyzed considering the work-hardening rate and the Hollomon work-hardening exponent after each strain path change applied to the AISI 409 steel. The results indicated the presence of preferential crystallographic orientation and the occurrence of transients on the work-hardening rate mainly for the sample sheared at 45° from the original rolling direction due to structural arrangements assumed by the AISI 409 steel after the strain path changes.

Effect of hierarchical multimodal microstructure evolution on tensile properties and fracture toughness of rapidly solidified Mg–Zn–Y–Al alloys with LPSO phase

High fracture toughness Mg96.75Zn0.85Y2.05Al0.35 alloys featuring a multimodal microstructure were developed by rapidly solidified (RS) ribbon-consolidation processing. A non-heat-treated alloy that was prepared by consolidating the as-quenched ribbons exhibited a high tensile yield strength of ∼500 MPa, an elongation of ∼5%, and a plane-strain fracture toughness (KIc) of ∼9.5 MPa m1/2. Microstructure of the non-heat-treated alloy consists of two matrices: coarse-worked grains with a high kernel average misorientation (KAM) (group 1) and ultra-fine dynamically recrystallized (DRXed) grains with an intermediate KAM (group 2). The formation of ultra-fine DRXed grains with the precipitation of fine LPSO phase strengthens the alloy, but causes work-softening. The heat-treated alloy that was prepared by consolidating the RS ribbons heat-treated at 738 K exhibited a good balance of a high KIc (∼15 MPa m1/2), a reasonable yield strength (∼400 MPa), and a large elongation (∼12%) with a positive work-hardening rate. The optimized pre-consolidation heat-treatment produces multimodal microstructure having three matrices; a third group of the fine DRXed grains with a low KAM was formed in addition to groups 1 and 2. The formation of hierarchical multimodal structure in the grain size and KAM evokes strain-hardening, which has a positive effect on the fracture toughness.

Plastic deformation of AA6061-T6 at elevated temperatures: Experiments and modeling

The temperature-dependent work-hardening of AA6061-T6 aluminum alloy is investigated using a combined experimental-numerical approach. Uniaxial tension experiments are performed from room temperature to 500 °C, and the force-displacement curves up to fracture are established. Both the yield strength and the work-hardening rate of the material decrease with increasing temperature. Despite the marked increase in the elongation-to-fracture, the uniform elongation remains limited, indicating the early appearance of diffuse necking in the elevated temperature tests. A simplified technique for identifying the work-hardening curves at elevated temperatures and beyond the limit of uniform deformation in uniaxial tension is proposed. The technique uses an isothermal, rate-dependent, finite element (FE) model of the experiments. The post-necking hardening curve is represented by a hybrid Swift/Voce hardening law combined with a form of Johnson-Cook strain-rate dependence. To identify the material model parameters at each temperature, an objective function that correlates the experimental and FE-predicted force-displacement curves is constructed and minimized. These model parameters are then fit with Fourier series across the temperature range considered here, providing smooth functions suitable for subsequent implementation in FE analyses of forming and structural problems. As an illustration, it is shown that a FE model utilizing these material parameters reproduces the full-field features of the elevated temperature experiments very well.

Excellent work-hardening in ZrCu/NiNb amorphous/amorphous nanolaminates

Work-hardening behavior could be rarely observed in amorphous alloys during plastic deformation because the dilation and softening effect often occur in shear bands. Here, we proposed a novel mechanism to realize an excellent work-hardening rate (R=dσdε) in ZrCu/NiNb amorphous/amorphous nanolaminates (A/ANLs), which is investigated by in-situ uniaxial micro-pillar compression tests. The work-hardening rate value (25.24 GPa) obtained in ZrCu/NiNb A/ANLs with single layer thickness (h) 5 nm and volume ration 1:1, is relatively high, when comparing with the values in other results that considered the effect of crystalline phases and structural heterogeneity on work-hardening rate in composites. Such a high work-hardening effect is attributed to serious suppression of shear transformation zones (STZs) percolation by amorphous/amorphous interfaces. This work-hardening effect increased sharply as h decreases to 5 nm.

Effect of carbon addition on microstructure and mechanical properties of as-cast nickel-based heavy density matrix alloy reinforced by high tungsten content

In present work, a novel carbon-doped interstitial strengthening nickel-based heavy density matrix alloy reinforced by high tungsten content (Ni-W-Co) was prepared by conventional casting technology using a laboratory vacuum induction melting (VIM) furnace. The effects of carbon addition on as-cast microstructure and phase constituents were characterized by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). And the tensile properties and microhardness were tested as well. Results demonstrated that the present heavy density alloy has a single-phase FCC structure and exhibits typical dendrite characteristics. The carbon content (0–0.021 wt%) presents little influence on as-cast microstructure and phase constituents, but significantly improves the mechanical properties. Both tensile strength and ductility of the matrix alloy were increased synchronously with the addition of interstitial carbon atoms on account of the interstitial strengthening. The tensile fracture morphology revealed the transition from complete ductile dominated features to a mixed fracture mode consisting of quasi cleavage and ductile fractures. Minor carbon addition can trigger an obvious increase for lattice parameters and thus contribute to the strength improvement, and the increase in lattice friction stress enhanced the work-hardening rate and postponed the necking of C-addition alloy compared with C-free alloy.

Manganese controlled transformation and twinning of the nanoscale austenite in low-carbon-medium-Mn steel

A Fe-10.5Mn-0.06C steel consisting of austenite and ferrite dual phases with a volume fraction ratio of 7:3 was fabricated via the quenching and partitioning (Q&P) processing. Tensile tests at various temperatures and strain rates were performed to reveal the mechanical properties of the steel, and the deformation microstructures were characterized by using TEM, t-EBSD and APT techniques. At a constant strain rate of 0.1 s−1, yield strength, tensile strength increase as the temperature decreases from 100 °C to −50 °C, and reach the highest values of 560 MPa and 1390 MPa at −50 °C, respectively. The specimens deformed at low temperatures (below 200 °C) exhibit a characteristic of three-stage work-hardening behavior, while those deformed at higher temperatures (200 and 300 °C) only show two-stage work-hardening curves. The extra hardening stage found at low temperatures is associated with the concurrent twinning and transformation in austenite with varying Mn contents as well as the interaction between twins and dislocations. With increasing temperature, the diffusion of Mn from austenite to ferrite is depressed, inhibiting the martensitic transformation. Consequently, the TRIP effect is weakened and the steel shows the reduced work-hardening rates at higher temperatures. In addition, a few nanoscale austenite residues (<200 nm) are remained even after −25 °C tensile deformtion, due to the highly localized Mn concentration of ∼15 wt%. These findings provide a guidance for designing advanced materials with combinations of ultrahigh strength and good ductility.

Evolution of the microstructure and mechanical properties of an sigma-hardened high-entropy alloy at different annealing temperatures

In this study, the evolution of the microstructure and mechanical properties of the Co34.5Cr30Ni26.5Al5.4W3.6 (at,%) high-entropy alloy was examined. This study aimed to provide valuable information for the design and modification of the mechanical properties of precipitation-hardened high/medium entropy alloys with partially recrystallized microstructures. With regard to alloy design, Md is a valuable parameter for predicting the formation of σ-phase, and the critical value ranges from 0.902 to 0.908. Alloying elements that strongly interact with principal elements can result in sluggish recrystallization, which facilitates the formation of partially recrystallized microstructures within a wider temperature range. Except for general defects, the σ-phase can also formed on reserved type-{111} slip planes. To regulate the proportion of recrystallized and non-recrystallized grains is the most effective means of controlling strength and ductility. Large σ particles can enhance strength, and a fully recrystallized alloy with large grains has a high work-hardening rate attributable to deformation twinning.

Dynamic mechanical properties and microstructure evolution of AlCoCrFeNi2.1 eutectic high-entropy alloy at different temperatures

The dynamic mechanical properties of the AlCoCrFeNi2.1 eutectic high-entropy alloy (EHEA) fabricated by drop-casting (DC) and suction-assisted casting (SC) are investigated under different strain rates and temperatures using Split Hopkinson Pressure Bar (SHPB) system. Microstructure analysis is conducted through SEM, EBSD and TEM to reveal the deformation and fracture mechanisms of the present EHEA. The yield strength and flow stresses for both the DC alloy and SC alloy increase with increasing strain rate, but decrease with increasing temperature. A mixture of ductile and brittle fracture morphologies exists in both the DC and SC EHEAs. Moreover, the SC alloy displays more shear dimples on the fracture surface, while brittle fracture features become dominant for the DC alloy. Abundant accumulation of dislocations in the quasi-static test produces slip traces in the FCC lamellar phase which further enhances the plasticity of the SC alloy. Meanwhile, the dislocation cells formed by high-density dislocation tangles at high strain rates, leading to apparent work hardening and strain rate sensitivity of the SC alloy. The adiabatic shear band (ASB) forms in the SC alloy before shear failure and the adjacent twisted and curved lamellar structures play a significant role in preventing shear localization. Overall, the SC alloy exhibits a stronger strain rate effect and better ductility than the DC alloy.