Strain Rate Sensitivity Coefficient Research Articles

Predicting the strain hardening behavior and constructing processing maps of a lightweight Fe–Mn–Al–C steel through phenomenological modelling

This research deals with predicting the strain hardening behavior and constructing the processing maps of a lightweight steel over a wide range of temperature. To achieve this, the tensile tests were conducted at temperatures of 100 °C–1100 °C under strain rates of 0.001, 0.01, and 0.1s−1 up to fracture. In order to predict the deformation behavior of the lightweight steel, strain compensated Arrhenius-type models were employed. Considering the wide temperature range under investigation, the activation energies and strain rate sensitivity coefficients substantially varied, therefore, three different temperature ranges of 25–200 °C, 300–600 °C, and 700–1000 °C were considered for the prediction of the flow stress level. To evaluate the accuracy of the applied models, the (i) root mean square error (RMSE), (ii) average absolute relative error (AARE), and (iii) correlation coefficient (R), were calculated as well-known statistical parameters. A good agreement was observed between the predicted and actual flow stress. Employing the predicted data, the strain hardening curves were plotted and power dissipation/instability maps were constructed at various strain levels and temperature ranges. The rapid hardening regions, the regions with high efficiency and instability regions were identified which would be valuable for industrialization of the experimented material.

A Study of the Superplastic Deformation Behavior of Low-Cost Ti-2Fe-0.1B Alloys.

Titanium alloys have high specific strength and corrosion resistance, which have promising applications in industry. However, the machinability of titanium alloys is limited due to their crystal lattice and physical properties. Thus, in recent years, the superplastic forming of titanium alloys has been intensively developing, in particular, forming at low temperatures and/or high strain rates. In this work, a tensile test of low-cost Ti-2Fe-0.1B alloys was carried out at a temperature of 550~750 °C and a strain rate of 1 × 10-3 s-1~1 × 10-2 s-1. The results showed that the alloy exhibited good superplasticity even at a high strain rate (1 × 10-2 s-1) and a low deformation temperature of 550 °C; the elongation of the alloy in this state reached 137.5%. The high strain rate sensitivity coefficient m (0.3) and the maximum elongation (452%) were obtained at a strain rate of 1 × 10-3 s-1 and a temperature of 750 °C. Characteristics of the microstructure showed that during superplastic deformation, the recrystallization and grain boundary sliding of the alloy phases were accelerated, which could be ascribed to the effect of the element Fe. At the same time, the TiB phase located around the primary elongated α grains could also induce dynamic recrystallization and dynamic globularization during deformation.

Establishing the hot working window for the forging of S32906 super duplex stainless steel through considering deformation parameter sensitivities

The evaluation of the hot workability of the super duplex stainless steel (SDSS) material still lacks scientific and theoretical basis, leading to the frequent occurrence of unacceptable defects in its forgings. In this study, a novel method for estimating the hot workability of S32906 SDSS was proposed and verified through forging. Firstly, the flow behavior and microstructural characteristics were demonstrated by conducting isothermal compression tests at the deformation temperature from 1000 °C to 1250 °C and the strain rate from 0.01 s−1 to 10 s−1. The influence of microstructure on flow and work hardening behaviors was correlated and displayed. Then, based on the deformation characteristics presented through the variations of strain rate sensitivity (SRS) and deformation temperature sensitivity (DTS) coefficients, the SRS and DTS maps were constructed and overlaid for obtaining the hot working window. Ultimately, a large plate type forging of S32906 SDSS applied in engineering was used to verify the applicability of the obtained window. The new method can provide an in-depth understanding of hot workability and enable control of the forming and microstructural properties for this unique material.

Hot workability optimization of W400 non-oriented silicon steel

Isothermal compression tests of W400 non-oriented silicon steel are performed at 0.01 to 10 s−1 and 850 to 1150 °C on a Gleeble thermo-mechanical simulator. Each stress-strain curve shows monotonous but slow increase of flow stress blessed with increasing strain. By introducing temperature into the strain rate exponent in Z parameter and proposing the temperature boundary principle, a revised constitutive pattern is built with a view to quantify flow stress versus temperature and strain rate accurately. Numerous sub-grains and sub-grain boundaries (GBs) are detected in the deformed grains, confirming the distortion energy to be reduced by dynamic recovery and thus slowing down the monotonous increase of flow stresses. Unusual discontinuous dynamic recrystallization is activated when strain rate and temperature is relatively higher, as confirmed by the random orientations of recrystallized grains. Analyses of GB shape and intergranular misorientation prove that local strain due to weak dynamic recovery leads to GB bulging and sub-GB formation, and thus activates the unusual discontinuous dynamic recrystallization. The distribution maps of strain rate sensitivity coefficient are constructed when the strain are 0.2–0.8. Based on high strain rate sensitivity coefficient, low deformation resistance and high GB stability, workability parameters are optimized as: temperature 1000–1150 °C, strain rate 0.01 to 10−0.5 s−1 and strain ≤0.6.

Stress relaxation behavior of low carbon steel at different temperatures * *National Science and Technology Major Project: 2017ZX04012001

In this paper, the stress relaxation behavior of Q235 with the initial tensile stress of 70, 85 and 100 MPa were investigated at different temperature. Based on the thermal activation theory, the stress relaxation model of Q235 steel was established, and the physical mechanism and deformation process in the stress relaxation process were revealed. The results shows that with the increase of temperature or initial stress, the nominal activation volume decreases, but the strain rate and the strain rate sensitivity coefficient increase. The repeated stress relaxation test shows that the stress release amount decreases with the increase of the number of cycles, and the higher the temperature, the smaller the effect of the number of cycles. Under the action of temperature and stress, the dislocation starts to move from the disordered bending shape in the original sample to the flat shape gradually. Moreover, the dislocation density decreases to less than 47.8% of the initial sample as the temperature increases and the initial stress decreases. It can be concluded that the dislocation motion is the core mechanism of stress relaxation of Q235 steel.

The influence of Ni on the contributions of the superplastic deformation mechanisms of the Al–Zn–Mg–Cr alloys

The Ni influence on the superplastic characteristics, the microstructure evolution and the contributions of the superplastic deformation mechanisms for Al-Zn-Mg-Cr-based alloys have been investigated. The alloys contained dispersoids enriched with Cr, Mg and a minor of Zn of a mean size of 140 nm and in addition the Al3Ni phase in the alloy with nickel. Al3Ni phase increased homogeneity and stablity grain structure during elevated annealing temperature and during superplastic deformation at 440°C. The mean grain size decreases from 7.7 to 7.3 µm before the onset of the deformation and from 10 to 8.6 µm after straining of 0.69. The dislocations aggregations near Al3Ni particles were revealed. The microstructure evolution was compared at the testing condition providing a similar value of the strain rate sensitivity coefficient m≈0.6. The grain boundary sliding contribution is twofold larger and the intragranular dislocation slip is three times smaller in the alloy with Al3Ni particles compared to nickel-free alloy. Al3Ni particles leads to more equiaxed finegrain structure and an increase elongation to failure.

Study on constitutive relationship of 6061 aluminum alloy based on Johnson-Cook model

Uniaxial tensile tests are conducted on 6061 aluminum alloy sheets at different strain rates of a certain temperature and different temperatures of a certain strain rate. The true stress-strain curves show that the flow stresses are negatively correlated with strain rates and temperatures. Based on the Johnson Cook (J-C) constitutive model, the modified J-C model is constructed by replacing the strain term with a Voce hardening model and correcting the strain rate sensitivity coefficient and the thermal softening exponent. Compared with the J-C model, the modified J-C model has a smaller average absolute error and more accurately describes the plastic stress-strain relationship of 6061 aluminum alloy under various deformation conditions. Furthermore, the modified J-C model is also used for numerical simulation of uniaxial tension. The good agreement between the experimental and simulated load-displacement curves further verifies the usefulness of the modified J-C model. Finally, the microscopic mechanism by which deformation speeds affect ductility is analyzed by scanning electron microscopy (SEM).

Room temperature deformation mechanisms of a Fe–Mn–Al–C steel

This study aims to investigate the deformation mechanisms of an austenite-based duplex Fe–Mn–Al–C steel at room-temperature through uniaxial tensile tests, strain rate sensitivity and stress relaxation analysis. Through numerical analysis and microstructural studies, this investigation reveals that increasing strain leads to the formation of low-angle boundaries (LABs) at the vicinity of grain boundaries. Consequently, these LABs play a facilitating role in the stress-assisted diffusion of carbon atoms, thereby triggering the dynamic strain aging (DSA) phenomenon. The evidence for this is substantiated by the strain rate sensitivity coefficient and stress relaxation results obtained from numerical analysis during uniaxial tensile tests. As deformation progresses, the misorientation of LABs increases, influencing the strain hardening behavior. The intensified DSA contributes to enhanced work hardening, while substructure development results in softening, creating a trade-off between these contrasting effects.

Effects of Mn addition on mechanical properties, fracture surface, and electrochemical corrosion resistance of CoCrFeNiAl high-entropy alloys

High-entropy alloys consisting of CoCrFeNiAl as the major elements and 2–5 at% Mn as the minor element were prepared using a vacuum arc melting method. The crystalline structures of the prepared alloys were identified by x-ray diffraction. Moreover, the mechanical properties of the alloys were examined under quasi-static (10−1, 10−2 and 10−3 s−1) and dynamic (3000, 4000, and 5000 s−1) loading conditions using a universal testing machine and split-Hopkinson pressure bar system, respectively. The experimental results showed that, for all of the HEA alloys, the flow stress and strain rate sensitivity coefficient increased with increasing strain rate. Among all the alloys, that with 3 at% Mn exhibited the best mechanical properties. A significant loss in plasticity was observed as the Mn content increased to 5 at%. The scanning electron microscope observations showed that the favorable mechanical properties of the alloy with 3 at% Mn were the result of a compact dimple structure, which enhanced the toughness. The HEA with 5 at% Mn showed the best electrochemical corrosion resistance among all the alloys due to the formation of dendritic structures at the grain boundaries.

Effect of Mo content on the microstructure, superplastic behavior, and mechanical properties of Ni and Fe-modified titanium alloys

Novel titanium-based alloys are required to increase the efficiency of superplastic forming technology and decrease energy consumption. For this purpose, the superplastic deformation behavior, strain-induced microstructure evolution in a temperature range of 625–775 °C, and post-deformation mechanical properties of Ti–4Al–1V–1Fe–1Ni-0.1B-xMo alloys (x = 1, 2.5, or 5 wt%) were investigated. The studied alloys demonstrated a stable flow with a high strain rate sensitivity coefficient m of 0.50–0.65 and an elongation-to-failure δ of 700–1000% at temperatures of 700–775 °C. Molybdenum insignificantly influenced superplastic deformation behavior at high temperatures due to a high fraction of the β phase of 22–62%. The Mo effect was significant at a low deformation temperature of 625 °C. At this temperature, an increase in Mo content from 1 to 5% provided the β-phase fraction above the critical value of ∼20% and increased the m-value from 0.4 to 0.5 and δ from ∼200 to ∼700%. Increasing Mo from 1 to 5% enhanced the post-deformation yield strength at room temperature by 180 MPa, the ultimate tensile strength by 170 MPa, and the ductility by 2.5%. Consequently, alloying Ti–4Al–1V–1Fe–1Ni-0.1B with 5% Mo provided an excellent combination of superplasticity at a low temperature of 625 °C and post-forming tensile mechanical properties.

Effect of Boron on the Microstructure, Superplastic Behavior, and Mechanical Properties of Ti-4Al-3Mo-1V Alloy.

The decrease of superplastic forming temperature and improvement of post-forming mechanical properties are important issues for titanium-based alloys. Ultrafine-grained and homogeneous microstructure are required to improve both processing and mechanical properties. This study focuses on the influence of 0.01-2 wt.% B (boron) on the microstructure and properties of Ti-4Al-3Mo-1V (wt.%) alloys. The microstructure evolution, superplasticity, and room temperature mechanical properties of boron-free and boron-modified alloys were investigated using light optical microscopy, scanning electron microscopy, electron backscatter diffraction, X-ray diffraction analysis, and uniaxial tensile tests. A trace addition of 0.01 to 0.1 wt.% B significantly refined prior β-grains and improved superplasticity. Alloys with minor B and B-free alloy exhibited similar superplastic elongations of 400-1000% in a temperature range of 700-875 °C and strain rate sensitivity coefficient m of 0.4-0.5. Along with this, a trace boron addition provided a stable flow and effectively reduced flow stress values, especially at low temperatures, that was explained by the acceleration of the recrystallization and globularization of the microstructure at the initial stage of superplastic deformation. Recrystallization-induced decrease in yield strength from 770 MPa to 680 MPa was observed with an increase in boron content from 0 to 0.1%. Post-forming heat treatment, including quenching and ageing, increased strength characteristics of the alloys with 0.01 and 0.1% boron by 90-140 MPa and insignificantly decreased ductility. Alloys with 1-2% B exhibited an opposite behavior. For the high-boron alloys, the refinement effect of the prior β-grains was not detected. A high fraction of borides of ~5-11% deteriorated the superplastic properties and drastically decreased ductility at room temperature. The alloy with 2% B demonstrated non-superplastic behavior and low level of strength properties; meanwhile, the alloy with 1% B exhibited superplasticity at 875 °C with elongation of ~500%, post-forming yield strength of 830 MPa, and ultimate tensile strength of 1020 MPa at room temperature. The differences between minor boron and high boron influence on the grain structure and properties were discussed and the mechanisms of the boron influence were suggested.

The influence of the heat generation during deformation on the mechanical properties and microstructure of the selected TWIP steels

The TWIP (Twinning Induced Plasticity) steels are one of the most promising materials in reducing the weight of vehicles. Despite a lot of research on TWIP steel, there are some issues that are not explained enough. Due to the future use of TWIP steel and the manufacturing of the final part by metal forming, three issues still need to be clarified. The first one, which is the most important, is the increase of the temperature due to the conversion of the deformation work into heat. TWIP steel has a high limit strain, strength and lower conductivity than conventional steel, therefore the heat generation of TWIP steel is greater than for other materials. The second and third issues are combined. They concern the influence of V microadditions on the stress–strain curves, the strain hardening coefficient n and the strain rate sensitivity coefficient m under cold deformation conditions. These properties determine the cold formability of TWIP steels. In the research, two TWIP steels were used with and without V microadditions (MnAl and MnAl-V steel). The special methodology using strain and temperature measurement systems as well as light and scanning electron microscopy (SEM) were applied. Research shows a significant increase of the temperature in the material due to high plastic deformations as well as a high level of yield stress. In the neck area, for the highest strain rate of 0,1 s -1, at the moment of rupture, the temperature reaches more than 200 °C. The difference between the average temperature in the rupture area and the maximum temperature is equal to 100° C. Its high increase can lead e.g. to changes in the deformation mechanism from twinning to dislocation gliding, which is also connected with a worsened workability, and thus also energy consumption of the bodywork elements. MnAl-V steel has better or similar ductility for the deep drawing in comparison to MnAl steel at low strain rates for almost isothermal conditions (constant temperature during deformation). However the MnAl steel has better ductility for the larger strain rates over 0.1 s−1 then there is large heat concentration in a very narrow area for MnAl-V steel. The obtained results are very important from an application point of view. The strain rate sensitivity coefficient m of the steel MnAl has very low, and even negative, values, which can make the production of complicated drawpieces difficult. Higher values of the strain rate sensitivity coefficient are exhibited by steel MnAl-V, i.e. at the level of 0,05, which is almost constant in the whole range of the obtained deformations.

Comparison of the Strain Rate Sensitivity in AZ31 and WE43 Magnesium Alloys under Different Loading Conditions

The initial texture effect of strain rate sensitivity response in magnesium alloys was studied using the quasi in situ electron backscatter diffraction technique. The strain accumulations, under uniaxial loading of both tensile and compression along the rolling direction, showed strain rate dependency. For the AZ31 magnesium sheets with strong basal texture (max intensity to 11.2), twinning first occurs at the onset of plastic deformation, resulting in macroscopic strain rate insensitivity. With further loading, the strain rate sensitivity significantly increases (with the strain rate sensitivity coefficient m increased from 0.0025 to 0.012), arising from the initiation of slip. For the WE43 alloy sheets with weak basal texture (max intensity to 2.6), the overall deformation is sensitive to strain rate under both tensile and compression. The twinning growth rate and twinned volume fraction have been used to identify whether the process is twin-dominated or slip-dominated during the plastic deformation of a magnesium alloy.

Mechanical properties of steel wires of 1670 MPa, 1770 MPa, and 1860 MPa grades under high strain rates and temperatures

In this study, the mechanical behavior under high strain rates and high temperatures of 1670 MPa, 1770 MPa, and 1860 MPa grades steel wires were investigated. Quasi-static tensile experiments (10−4 s−1), split Hopkinson compression bar experiments (102–103 s−1) and high-temperature tensile experiments were conducted (20–900 °C). A total of 89 samples were tested for the study. Stress-strain curves were obtained for different strain rates and different temperatures. The experiments indicated that the strain rate had an obvious influence on the behavior of high-strength steel wires, both the yield and ultimate strength increased with increasing strain rate. The strength ratio and strain rate sensitivity coefficients of high-strength steel wires were investigated for high strain rates. The mechanical properties of the steel wire are significantly reduced under high temperatures. The Cowper-Symonds (C-S) and Johnson-Cook (J-C) constitutive models were determined using experimental data. By contrasting the proposed models with the experiment data, the precision of the constitutive models was confirmed.

Superplastic Behavior and Microstructural Features of the VT6 Titanium Alloy with an Ultrafine-Grained Structure during Upsetting

In this paper, the superplastic behavior of the two-phase titanium alloy VT6 with an ultrafine-grained (UFG) structure produced by equal-channel angular pressing is examined. The deformation of specimens with a UFG structure was performed by upsetting in a temperature range of 650-750 °C and strain rate range of 1 × 10-4-5 × 10-1 s-1. Under these conditions, an increased strain-rate sensitivity coefficient m was observed. The calculation of apparent activation energy showed values in a range of 160-200 kJ/mol while the superplastic flow of the VT6 alloy was occurring. When superplastic behavior (SPB) was impeded, the energy Q grew considerably, indicating a change in mechanism from grain-boundary sliding (GBS) to bulk diffusion. A change in temperature and strain rate influenced the development of superplastic flow and the balance of relaxation processes. Microstructural analysis shows that the UFG state is preserved at upsetting temperatures of 650 and 700 °C. A decrease in strain rate and/or an increase in upsetting temperature promoted a more active development of recrystallization and grain growth, as well as α2-phase formation. In a certain temperature and strain-rate range of the UFG VT6 alloy, α2-phase plates were found, the formation of which was controlled by diffusion. The effect of the α2-phase on the alloy's mechanical behavior is discussed.

Low-Temperature Superplasticity and High Strength in the Al 2024 Alloy with Ultrafine Grains.

This study aims to achieve an ultrafine-grained (UFG) Al 2024 alloy superplasticity at temperatures lower than the traditional ones for commercial Al alloys (400-500 °C). The UFG structure with a mean grain size of 100 nm produced in the alloy by high-pressure torsion at room temperature provided a very high strength-microhardness (HV0.1) of 286 ± 4, offset yield strength (σ0.2) of 828 ± 9 MPa, and ultimate tensile strength (σUTS) of 871 ± 6 MPa at elongation to failure (δ) of 7 ± 0.2%. Complex tensile tests were performed at temperatures from 190 to 270 °C and strain rates from 10-2 to 5 × 10-5 s-1, and the values of flow stress, total elongation and strain rate-sensitivity coefficient were determined. The UFG alloy was shown to exhibit superplastic behavior at test temperatures of 240 and 270 °C. For the first time, 400% elongation was achieved in the alloy at an unusually low temperature of 270 °C (0.56 Tm) and strain rate of 10-3 s-1. The UFG 2024 alloy after superplastic deformation was found to have higher strength (150-160 HV) than that after the standard strengthening heat treatment T6.

Experimental and numerical analysis of dynamic splitting mechanical properties and crack propagation for frozen sandstone

To reveal the dynamic tensile properties and crack growth law of frozen sandstone under impact loading, dynamic splitting tests (−30–20 °C) with different strain rates were carried out using a split Hopkinson pressure bar (SHPB), and the crack growth process of the specimens was captured using a high-speed camera. The study focused on the analysis of dynamic tensile mechanical properties, energy dissipation, crack growth, and failure modes of frozen sandstone. Numerical simulation analyses were also performed using LS-DYNA. The results indicated that: (1) The dynamic tensile strength has an obvious strain rate enhancement effect, and the strain rate sensitivity coefficient increased with a decrease in temperature. The Logistic function can characterize the relationship between the dynamic strain rate enhancement factor and the strain rate of frozen sandstone. (2) In the dynamic Brazilian disk (BD) test, the energy absorption rate showed a transition between the strain rates of 40 s−1 and 50 s−1, and there were two main failure modes of the specimen. The Y-direction secondary crack in mode II was caused by tensile stress in the Z-direction. (3) In the dynamic BD test, the central main crack (CMC) did not occur at the central position first, and its Z-direction propagation rate was linear with the strain rate. In the dynamic flattened Brazilian disk (FBD) test, the condition of CMC initiation was that the platform loading angle (2α) was greater than 10°. The dynamic tensile strength increased with an increase in 2α, and the correction coefficient was introduced in the calculation. This study can serve as a theoretical reference and basis for the study of the dynamic tensile properties of rock-like materials.

Effect of Sc, Hf, and Yb Additions on Superplasticity of a Fine-Grained Al-0.4%Zr Alloy

This research was undertaken to study the way deformation behaves in ultrafine-grained (UFG)-conducting Al-Zr alloys doped with Sc, Hf, and Yb. All in all, eight alloys were studied with zirconium partially replaced by Sc, Hf, and/or Yb. Doping elements (X = Zr, Sc, Hf, Yb) in the alloys totaled 0.4 wt.%. The choice of doping elements was conditioned by the possible precipitation of Al3X particles with L12 structure in the course of annealing these alloys. Such particles provide higher thermal stability of a nonequilibrium UFG microstructure. Initial coarse-grained samples were obtained by induction casting. A UFG microstructure in the alloys was formed by equal-channel angular pressing (ECAP) at 225 °C. Superplasticity tests were carried out at temperatures ranging from 300 to 500 °C and strain rates varying between 3.3 × 10−4 and 3.3 × 10−1 s−1. The highest values of elongation to failure are observed in Sc-doped alloys. A UFG Al-0.2%Zr-0.1%Sc-0.1%Hf alloy has maximum ductility: at 450 °C and a strain rate of 3.3 × 10−3 s−1, relative elongation to failure reaches 765%. At the onset of superplasticity, stress (σ)–strain (ε) curves are characterized by a stage of homogeneous (uniform) strain and a long stage of localized plastic flow. The dependence of homogeneous (uniform) strain (εeq) on test temperature in UFG Sc-doped alloys is increasing uniformly, which is not the case for other UFG alloys, with εeq(T) dependence peaking at 350–400 °C. The strain rate sensitivity coefficient of flow stress m is small and does not exceed 0.26–0.3 at 400–500 °C. In UFG alloys containing no Sc, the m coefficient is observed to go down to 0.12–0.18 at 500 °C. It has been suggested that lower m values are driven by intensive grain growth and pore formation in large Al3X particles, which develop specifically at an ingot crystallization stage.

Влияние состояния границ зерен на эффект пластификации в ультрамелкозернистом сплаве Al-0.4Zr

The influence of small additional deformation by cold rolling (CR) on the microstructure and mechanical properties of ultrafine-grained (UFG) Al–0.4Zr alloy structured by high pressure torsion (HPT) has been studied. The results are compared with the application of small additional deformation by HPT, which, after low-temperature annealing, leads to a substantial increase in ductility (plasticization effect) with small decrease in strength. It is shown that, in contrast to the additional deformation of HPT, the deformation of CR after intermediate low-temperature annealing leads to a sharp drop in plasticity to ~2%, while the strength increases to ~275 MPa. The key role of the nonequilibrium state of grain boundaries in the manifestation of the plasticization effect in the UFG Al–0.4Zr alloy is revealed. A new approach is proposed for simultaneously increasing the strength and ductility of the UFG Al–0.4Zr alloy due to a small additional deformation by CR without intermediate annealing. As a result of this approach, a significant increase in strength by ~30% (ultimate tensile strength ~223 MPa) was achieved with a simultaneous increase in ductility up to ~26%, which is associated with an increase in the strain hardening rate due to an increase in the density of lattice dislocations in the UFG structure with nonequilibrium grain boundaries. The strain rate sensitivity and strain hardening coefficients have been determined for the UFG Al–0.4Zr alloy in various states.

Influence of decreased temperature on the plasticization effect in high-strength Al-Cu-Zr alloy

The influence of deformation temperature of tensile test on the mechanical properties of ultrafine grained (UFG) Al-Cu-Zr alloy in three different states: after high pressure torsion (HPT), subsequent low-temperature annealing as well as after annealing and a small additional deformation has been studied for the first time. The UFG structure was formed by HPT processing. The temperature dependences of the yield stress and elongation to failure under uniaxial tension in the temperature range of 77–293 K were obtained for all three states. The effect of increasing ductility from ∼3–5 to 11 % (the plasticization effect) at room temperature while maintaining a high strength of ∼465 MPa was observed after deformation-heat treatment (DHT), consisting of annealing and additional deformation. The plasticization effect decreases monotonically with decreasing temperature of tensile test and completely disappears at ∼223 K. In the temperature range 223–293 K, the temperature sensitivity of the yield stress and the value of activation energy (Q) of plastic flow differ in all three states, which is related to the changes in the grain boundary (GB) structure (dislocation density, size and shape of Al2Cu nanoprecipitates). In the temperature range of 77–223 K, the temperature sensitivity of the yield stress does not depend on the state of GBs. The plasticization effect at room temperature is preserved when the strain rate is changed from 10−4 to 10−3 s−1 and sharply decreases as strain rate is further increased. The strain rate sensitivity coefficient (m) for the UFG Al-1.47Cu-0.34Zr (wt%) alloy was determined in the states before and after DHT. The results and relevant mechanisms are analyzed by using the resulting m valuе and Q values as well as the observations of specific features of GB structure.