Microstructure Evolution,Constitutive Modelling,and Superplastic Forming of Experimental 6XXX-Type Alloys Processed with Different Thermomechanical Treatments

This study focused on the microstructural analysis, superplasticity, modeling of superplastic deformation behavior, and superplastic forming tests of the Al-Mg-Si-Cu-based alloy modified with Fe, Ni, Sc, and Zr. The effect of the thermomechanical treatment with various proportions of hot/cold rolling degrees on the secondary particle distribution and deformation behavior was studied. The increase in hot rolling degree increased the homogeneity of the particle distribution in the aluminum-based solid solution that improved superplastic properties, providing an elongation of ~470–500% at increased strain rates of (0.5–1) × 10⁻² s⁻¹. A constitutive model based on Arrhenius and Beckofen equations was used to describe and predict the superplastic flow behavior of the alloy studied. Model complex-shaped parts were processed by superplastic forming at two strain rates. The proposed strain rate of 1 × 10⁻² s⁻¹ provided a low thickness variation and a high quality of the experimental parts. The residual cavitation after superplastic forming was also large at the low strain rate of 2 × 10⁻³ s⁻¹ and significantly smaller at 1 × 10⁻² s⁻¹. Coarse Al₉FeNi particles did not stimulate the cavitation process and were effective to provide the superplasticity of alloys studied at high strain rates, whereas cavities were predominately observed near coarse Mg₂Si particles, which act as nucleation places for cavities during superplastic deformation and forming.     

Tensile Behavior,Constitutive Model,and Deformation Mechanisms of MarBN Steel at Various Temperatures and Strain Rates

To reduce harmful gas emission and improve the operational efficiency, advanced ultra-supercritical power plants put forward higher requirements on the high temperature mechanical properties of applied materials. In this paper, the tensile behavior and deformation mechanisms of MarBN steel are discussed at different strain rates (5 × 10⁻³ s⁻¹, 5 × 10⁻⁴ s⁻¹, and 5 × 10⁻⁵ s⁻¹) under room temperature and 630 °C. The results show that the tensile behavior of the alloy is dependent on temperature and strain rate, which derived from the balance between the average dislocation velocity and dislocation density. Furthermore, observed dynamic recrystallized grains under severe deformation reveal the existence of dynamic recovery at 630 °C, which increases the elongation compared to room temperature. Finally, three typical constitutive equations are used to quantitatively describe the tensile deformation behavior of MarBN steel under different strain rates and temperatures. Meanwhile, the constitutive model of flow stress for MarBN steel is developed based on the hyperbolic sine law.     

Microstructural Evolution and Dynamic Softening Mechanisms of Al-Zn-Mg-Cu Alloy during Hot Compressive Deformation

The hot deformation behavior and microstructural evolution of an Al-Zn-Mg-Cu (7150) alloy was studied during hot compression at various temperatures (300 to 450 °C) and strain rates (0.001 to 10 s⁻¹). A decline ratio map of flow stresses was proposed and divided into five deformation domains, in which the flow stress behavior was correlated with different microstructures and dynamic softening mechanisms. The results reveal that the dynamic recovery is the sole softening mechanism at temperatures of 300 to 400 °C with various strain rates and at temperatures of 400 to 450 °C with strain rates between 1 and 10 s⁻¹. The level of dynamic recovery increases with increasing temperature and with decreasing strain rate. At the high deformation temperature of 450 °C with strain rates of 0.001 to 0.1 s⁻¹, a partially recrystallized microstructure was observed, and the dynamic recrystallization (DRX) provided an alternative softening mechanism. Two kinds of DRX might operate at the high temperature, in which discontinuous dynamic recrystallization was involved at higher strain rates and continuous dynamic recrystallization was implied at lower strain rates.     

Study on the Hot Deformation Behavior of Stainless Steel AISI 321

In this study, the hot deformation behavior of austenitic Ti-modified AISI 321 steel with a relatively high content of carbon (0.07 wt.%) and titanium (0.50 wt.%) was studied in the temperature range of 1000–1280 °C and strain rates in the range of 0.01–1 s⁻¹. Hot deformation was carried out with uniaxial compression of cylindrical specimens on a Gleeble 3800 thermomechanical simulator. It is shown that the flow stress increased with a decrease in the deformation temperature and an increase in the strain rate. The shape of the stress-strain curves indicates that, at high temperatures and low strain rates, the hot deformation of AISI 321 steel was accompanied by dynamic recrystallization. The passage of dynamic recrystallization was confirmed by microstructural studies. Hyperbolic sine type of constitutive equation with deformation activation energy Q = 444.2 kJ·mol⁻¹ was established by analyzing the experimental flow stresses. The power-law dependences of the critical strain necessary for the onset of dynamic recrystallization and the size of recrystallized grains on the Zener–Hollomon parameter were established. The value of the parameter Z = 5.6 × 10¹⁵ was determined, above which the dynamic recrystallization was abruptly suppressed in the steel under study. It is speculated that the suppression of dynamic recrystallization occurs due to dispersed precipitates of titanium carbonitrides.     

Comparison in Deformation Behavior,Microstructure, and Failure Mechanism of Nickel Base Alloy 625 under Two Strain Rates

Tensile deformation behavior and microstructure of nickel-base superalloy Inconel 625 are investigated under different strain rates of 5 × 10⁻⁴ s⁻¹ and 5 × 10⁻⁵ s⁻¹. According to the experimental results, yield strength and ultimate tensile strength of the alloy increase with the increase in strain rate in room temperature. Microstructure results indicate that the size of dimples is smaller in the tensile fracture surface at low strain rate than the high strain rate, and the number of dimples is also related to the strain rates and twins appear earlier in the specimens with higher strain rates. Apart from Hollomon and Ludwik functions, a new formula considering the variation trend of strength in different deformation stages is deduced and introduced, which fit closer to the tensile curves of the 625 alloy used in the present work at both strain rates. Furthermore, the Schmid factors of tensile samples under two strain rates are calculated and discussed. In the end, typical work hardening behavior resulting from the dislocations slip behavior under different strain rates is observed, and a shearing phenomenon of slip lines cross through the δ precipitates due to the movement of dislocations is also be note.     

Application of the Strain Compensation Model and Processing Maps for Description of Hot Deformation Behavior of Metastable β Titanium Alloy

The flow behavior of metastable β titanium alloy was investigated basing on isothermal hot compression tests performed on Gleeble 3800 thermomechanical simulator at near and above β transus temperatures. The flow stress curves were obtained for deformation temperature range of 800–1100 °C and strain rate range of 0.01–100 s⁻¹. The strain compensated constitutive model was developed using the Arrhenius-type equation. The high correlation coefficient (R) as well as low average absolute relative error (AARE) between the experimental and the calculated data confirmed a high accuracy of the developed model. The dynamic material modeling in combination with the Prasad stability criterion made it possible to generate processing maps for the investigated processing temperature, strain and strain rate ranges. The high material flow stability under investigated deformation conditions was revealed. The microstructural analysis provided additional information regarding the flow behavior and predominant deformation mechanism. It was found that dynamic recovery (DRV) was the main mechanism operating during the deformation of the investigated β titanium alloy.     

Mechanical Behavior of Titanium Based Metal Matrix Composites Reinforced with TiC or TiB Particles under Quasi-Static and High Strain-Rate Compression

The mechanical behavior of titanium alloys has been mostly studied in quasi-static conditions when the strain rate does not exceed 10 s⁻¹, while the studies performed in dynamic settings specifically for Ti-based composites are limited. Such data are critical to prevent the “strength margin” approach, which is used to assure the part performance under dynamic conditions in the absence of relevant data. The purpose of this study was to obtain data on the mechanical behavior of Ti-based composites under dynamic condition. The Metal Matrix Composites (MMC) on the base of the alloy Ti-6Al-4V (wt.%) were made using Blended Elemental Powder Metallurgy with different amounts of reinforcing particles: 5, 10, and 20% of TiC or 5, 10% (vol.) of TiB. Composites were studied at high strain rate compression ~1–3·10³·s⁻¹ using the split Hopkinson pressure bar. Mechanical behavior was analyzed considering strain rate, phase composition, microstructure, and strain energy (SE). It is shown that for the strain rates up to 1920 s⁻¹, the strength and SE of MMC with 5% TiC are substantially higher compared to particles free alloy. The particles TiC localize the plastic deformation at the micro level, and fracturing occurs mainly by crushing particles and their aggregates. TiB MMCs have a finer grain structure and different mechanical behavior. MMC with 5 and 10% TiB do not break down at strain rates up to almost 3000 s⁻¹; and 10% MMC surpasses other materials in the SE at strain rates exceeding 2200 s⁻¹. The deformation mechanism of MMCs was evaluated.     

Microstructure,Hot Deformation Behavior,and Recrystallization Behavior of Zn-1Fe-1Mg Alloy under Isothermal Compression

Nowadays, wrought zinc-based biodegradable alloys are favored by researchers, due to their excellent mechanical properties and suitable degradation rates. However, there are few research studies on their thermal deformation behavior at present. This study took Zn-1Fe-1Mg and explored its microstructural change, deformation, recrystallization behavior and processing map by means of the thermal simulation experiment, at temperatures ranging from 235 °C to 340 °C and strain rates ranging from 10⁻² s⁻¹ to 10 s⁻¹. The constitutive model was constructed using the Arrhenius formula. The results indicated that the evolution of microstructure included the dynamic recrystallization (DRX) of the Zn matrix, the spheroidization of the Mg₂Zn₁₁ phase, and breaking of the FeZn₁₃ phase. The subgrains observed within the deformed grain resulted mainly from continuous dynamic recrystallization (CDRX). The precipitated FeZn₁₃ grains overlapped with the precipitated MgZn₂ from the matrix, thus forming a spine-like structure at the phase interface. After compression, the alloy possessed a strong basal texture. Affected by the change of Zn twins, textural strength decreased at first and then increased as the deformation temperature rose. There was only a small unstable region in the processing map, indicating that the alloy exhibited good machinability.     

Johnson–Cook Parameter Identification for Commercially Pure Titanium at Room Temperature under Quasi-Static Strain Rates

Background: To simulate mechanical shocks on an intracranial implant called WIMAGINE^®, Clinatec chose a Johnson–Cook model to account for the viscoplastic behavior of grade 2 titanium in a dynamic study using Radioss^©. Methods: Thirty tensile specimens were subjected to tensile tests at room temperature, and the influence of the strain rate (8 × 10⁻³ and 8 × 10⁻² s⁻¹) and sandblasting was analyzed. Relaxations were included in the tests to analyze viscosity phenomena. Results: A whole set of parameters was identified for the elastic and plastic parts. Strain rate influence on stress was negligible at these strain rates. As expected, the sandblasting hardened the material during the tests by decreasing the hardening parameters, while local necking occurred at an earlier strain. Conclusions: This article provides the parameters of a Johnson–Cook model to simulate the elastoplastic behavior of pure titanium (T40, grade 2) in Finite Element Model (FEM) software.     

Microstructure and Constitutive Equation of Hot Compressive Fe-15Mn-15Al-5Ni-1C Low-Density Steel

The hot deformation behavior and dynamic recrystallization (DRX) of Fe-15Mn-15Al-5Ni-1C low-density steel in the as-cast state was investigated via hot compression experiments over temperature and strain rate ranges of 925 to 1150 °C and 0.01 to 10 s⁻¹, respectively. A constitutive equation and a critical DRX model of the Fe-15Mn-15Al-5Ni-1C low-density steel were also constructed. The results showed that higher strain rates resulted in significant work hardening and subsequent rapid softening of the Fe-15Mn-15Al-5Ni-1C low-density steel, while lower strain rates resulted in predominantly steady-state flow behavior. The activation energy of deformation for the Fe-15Mn-15Al-5Ni-1C low-density steel was Q = 540 kJ mol⁻¹ and the stress index was n = 4. The hot deformation mechanism was solute dragging and dislocation climbing, which was controlled by the strain rate. Increasing the deformation temperature or strain rate reduced the critical stress value σ_c of the DRX of the Fe-15Mn-15Al-5Ni-1C low-density steel and contributed to the DRX of austenite and δ-ferrite. The Fe-15Mn-15Al-5Ni-1C low-density steel after the hot compression deformation was mainly composed of austenite, ferrite, and κ carbide phases.     

Hot Deformation Behaviour and Constitutive Equation of Mg-9Gd-4Y-2Zn-0.5Zr Alloy

The thermal deformation behaviour of Mg-9Gd-4Y-2Zn-0.5Zr alloy at temperatures of 360–480 °C, strain rates of 0.001–1 s⁻¹ and a maximum deformation degree of 60% was investigated in uniaxial hot compression experiments on a Gleeble 3800 thermomechanical simulator. A constitutive equation suitable for plastic deformation was constructed from the Arrhenius equation. The experimental results indicate that due to work hardening, the flow stress of the alloy rapidly reached peak stress with increased strain in the initial deformation stage and then began to decrease and stabilize, indicating that the deformation behaviour of the alloy conformed to steady-state rheological characteristics. The average deformation activation energy of this alloy was Q = 223.334 kJ·mol⁻¹. Moreover, a processing map based on material dynamic modelling was established, and the law describing the influence of the machining parameters on deformation was obtained. The experimental results indicate that the effects of deformation temperature, strain rate and strain magnitude on the peak dissipation efficiency factor and instability range were highly significant. With the increase in the strain variable, the flow instability range increased gradually, but the coefficient of the peak power dissipation rate decreased gradually. The optimum deformation temperature and strain rate of this alloy during hot working were 400–480 °C and 0.001–0.01 s⁻¹, respectively.     

Monitoring Dynamic Recrystallisation in Bioresorbable Alloy Mg-1Zn-0.2Ca by Means of an In Situ Acoustic Emission Technique

The tensile behaviour of the biocompatible alloy Mg-1Zn-0.2Ca (in wt.%) in the fine-grained state, obtained by severe plastic deformation via multiaxial isothermal forging, has been investigated in a wide range of temperatures (20 ÷ 300) °C and strain rates (5 × 10⁻⁴ ÷ 2 × 10⁻²) s⁻¹ with the measurements of acoustic emission (AE). The dependences of mechanical properties, including the yield stress, ultimate strength, ductility, and the strain-hardening rate, on the test temperature and strain rate, were obtained and discussed. It is shown for the first time that an acoustic emission method is an effective tool for in situ monitoring of the dynamic recrystallisation (DRX) process. The specific behaviour of the acoustic emission spectral density reflected by its median frequency as a function of strain at various temperatures can serve as an indicator of the DRX process’s completeness.     

Dynamic Deformation Behavior and Fracture Characteristics of a near α TA31 Titanium Alloy at High Strain Rates

The quasi-static and dynamic impact compression tests of the TA31 titanium alloy were conducted at the strain rates from 0.001 s⁻¹ to 4000 s⁻¹ and deformation temperatures from 293 K to 773 K, and the TA31 titanium alloy showed typical elastic-plastic characteristics. In the initial stage of compression (elastic deformation), the stress and strain are proportional, and the stress–strain curve is a straight line. In the plastic deformation stage, the flow stress decreases significantly with the increase of deformation temperature, while the strain rate has no significant effect on the flow stress during dynamic compression. A constitutive model has been established to predict the flow stress, and the relative error is 2.32%. It is shown by observing the microstructure that when the deformation temperature is 293 °C, and the strain rate reaches 1600 s⁻¹, a shear band with an angle of about 45° to the axial direction of the specimen appears, and the severe shear deformation makes the α phase in the shear band fibrous and contains high-density dislocations. The formation process of the shear band and its influence on fracture are analyzed and discussed.     

Mechanical and Gamma Ray Absorption Behavior of PbO-WO3-Na2O-MgO-B2O3 Glasses in the Low Energy Range

The Makishima and Mackenzie model has been used to determine the mechanical properties of the PbO-WO₃-Na₂O-MgO-B₂O₃ glass system. The number of bonds per unit volume of the glasses (n_b) increases from 9.40 × 10²² to 10.09 × 10²² cm⁻³ as the PbO content increases from 30 to 50 mol%. The Poisson’s ratio (σ) for the examined glasses falls between 0.174 and 0.210. The value of the fractal bond connectivity (d) for the present glasses ranges from 3.08 to 3.59. Gamma photon and fast neutron shielding parameters were evaluated via Phy-X/PSD, while that of electrons were calculated via the ESTAR platform. Analysis of the parameters showed that both photon and electron attenuation ability improve with the PbO content. The fast neutron removal cross section of the glasses varies from 0.094–0.102 cm⁻¹ as PbO molar content reduced from 50–30 mol%. Further analysis of shielding parameters of the investigated glass system showed that they possess good potential to function in radiation protection applications.     

Characterization of Hot Deformation of near Alpha Titanium Alloy Prepared by TiH2-Based Powder Metallurgy

TiH₂-basd powder metallurgy (PM) is one of the effective ways to prepared high temperature titanium alloy. To study the thermomechanical behavior of near-α titanium alloy and proper design of hot forming, isothermal compression test of TiH₂-based PM near-α type Ti-5.05Al-3.69Zr-1.96Sn-0.32Mo-0.29Si (Ti-1100) alloy was performed at temperatures of 1123–1323 K, strain rates of 0.01-1 s⁻¹, and maximum deformation degree of 60%. The hot deformation characteristics of alloy were analyzed by strain hardening exponent (n), strain rate sensitivity (m), and processing map, along with microstructure observation. The flow stress revealed that the difference in softening/hardening behavior at temperature of 1273–1323 K and the strain rate of 1 s⁻¹ compared to the lower deformation temperature and strain rate. The strain hardening exponents at temperatures of 1123 K are all negative under all strain rates, and the most severe flow softening with minimum value of n was observed at 1123 K and 1 s⁻¹. The strain rate sensitives showed that the peak region with m value greater than 0.5 generally appeared in the high temperature range of 1273–1323 K, while strain rate sensitivity at low temperature behaved differently with strain rates. The processing map developed for strain of 0.6 exhibited high power dissipation efficiency at high temperatures of 1273–1323 K and a low strain rate of 0.01 s⁻¹, due to microstructure evolution of β phase. The decrease of strain rate at 1323 K resulted in the formation of globularization of α lamellae. The instability domain of flow behavior was identified in the temperature range of 1123–1173 K and at the strain rate higher than 0.01 s⁻¹ reflecting the localized plastic flow and adiabatic shear banding, and inhomogenous microstructure. The variation of power dissipation energy (η) slope with strain demonstrated that the power dissipation mechanism during hot deformation has been changed from temperature-dependent to microstructure-dependent with the increase of temperature for the alloy deformed at 0.1 s⁻¹. Eventually, the optimum processing range to deform the material is at 1273–1323 K and a strain rate range of 0.01–0.165 s⁻¹ (lnε˙ = −4.6–−1.8).     

Constitutive Descriptions and Restoration Mechanisms of a Fe-17Cr Alloy during Deformation at Temperatures of 700–1000 °C

The deformation behavior for highly purified Fe-17Cr alloy was investigated at 700~1000 °C and 0.5~10 s⁻¹. The microstructure evolution and corresponding mechanism during deformation were studied in-depth, using electron backscattering diffraction, transmission electron microscopy and precession electron diffraction. During deformation, dynamic recrystallization (DRX) occurred, along with extensive dynamic recovery, and the active DRX mechanism depended on deformation conditions. At higher Zener-Hollomon parameter (Z ≥ 5.93 × 10²⁷ s⁻¹), the development of the shear band was promoted, and then continuous DRX was induced by the formation and intersection shear band. At lower Zener-Hollomon parameter (Z ≤ 3.10 × 10²⁵ s⁻¹), the nucleation of the new grain was attributed to the combination of continuous DRX by uniform increase in misorientation between subgrains and discontinuous DRX by grain boundary bulging, and with increasing temperature, the effect of the former became weaker, whereas the effect of the latter became stronger. The DRX grain size increased with the temperature. For alleviating ridging, it seems advantageous to activate the continuous DRX induced by shear band through hot deformation with higher Z. In addition, the modified Johnson-Cook and Arrhenius-type models by conventional way were developed, and the modified Johnson-Cook model was developed, using the proposed way, by considering strain dependency of the material parameters. The Arrhenius-type model was also modified by using the proposed way, through distinguishing stress levels for acquiring partial parameter and through employing peak stress to determine the activation energy and considering strain dependency of only other parameters for compensating strain. According to our comparative analyses, the modified Arrhenius-type model by the proposed approach, which is suggested to model hot-deformation behavior for metals having only ferrite, could offer a more accurate prediction of flow behavior as compared to other developed models.     

Hot Deformation Behavior and Microstructural Evolution Based on the Processing Map of Dual-Phase Mg-Li Based Alloy

The deformation behavior of the as-extruded Mg-Li-Al-Zn-Si alloy was studied by conducting a hot compression test, with a temperature range of 180–330 °C and a strain rate range of 0.01–10 s⁻¹. The constitutive relationship of flow stress, temperature, and strain rate was expressed by the Zener–Hollomon parameter and included the Arrhenius term. By considering the effect of strain on the material constants, the flow stress at 240–330 °C could be precisely predicted with the constitutive equation (incorporating the influence of strain). A processing map was established at the strain of 0.7. The unsafe domains that are characterized by uneven microstructures were detected at low temperatures (<230 °C) or high temperatures (>280 °C), with high strain rates (>1 s⁻¹). The optimum hot deformation region was obtained at a medium temperature (270–300 °C), with a peak power dissipation efficiency of 0.44. The microstructural evolution in different domains is investigated. The unstable domains are characterized by a non-uniform flow behavior and uneven microstructure. The observation showed that the dynamic recrystallization (DRX) process could easily occur at the safe domain with high power dissipation efficiency. For the α-phase, some features of continuous dynamic recrystallization can be found. The triple points serve as prominent nucleation sites for the β-phase DRX grains and the growth in the grains was carried out by subgrain boundary migration. The microstructure exhibits characteristics of discontinuous dynamic recrystallization.     

Hot Deformation and Dynamic Recrystallisation Behaviour of Twin-Roll Cast Mg-6.8Y-2.5Zn-0.4Zr Magnesium Alloy

In this work, the deformation behaviour of a twin-roll cast (TRC) Mg-6.8Y-2.5Zn-0.4Zr alloy during plane strain compression was characterised by high-temperature testing. Based on the experimental data, the values of strain-rate sensitivity, the efficiency of power dissipation and the instability parameter were investigated under the conditions of various hot deformation parameters. In contrast to conventionally cast material, no lamellae of the LPSO (long period stacking ordered) phase were precipitated in the magnesium matrix after TRC. The precipitation of fine lamellar LPSO phases only occurred during cooling to forming temperature after the heat treatment. Dynamic recrystallization (DRX) hardly occurred during deformation at temperatures between 350 °C and 400 °C. This can be attributed to the precipitation of the lamellar LSPO phases, which contribute to retardation of the DRX process. At higher deformation temperatures and strain rates DRX is pronounced and the twin-induced (TRDX) as well as continuous dynamic recrystallization could be identified as the dominant softening mechanisms. The processing maps were established by superimposing the instability map over the power dissipation map, this being associated with microstructural evolution analysis in the hot deformation processes. Two instability zones could be recognised for the twin-roll cast and heat-treated Mg-6.8Y-2.5Zn-0.4Zr alloy: (1) 350 °C to 460 °C and 0.01 s⁻¹ to 0.3 s⁻¹ and (2) 485 °C to 525 °C and 2.5 s⁻¹ to 10 s⁻¹, where deformation is not favourable.     

Effect of Strain Rate and Temperature on Tensile and Fracture Performance of AA2050-T84 Alloy

AA2050-T84 alloy is widely used in primary structures of modern transport aircraft. AA2050-T84 is established as a low-density aluminum alloy with improved Young’s modulus, less anisotropy, and temperature-dependent mechanical properties. During flights, loading rate and temperature variation in aircraft engine subsequent parts are commonly observed. The present work focuses on the effect of loading rate and temperature on tensile and fracture properties of the 50 mm thick (2-inch) AA2050-T84 alloy plate. Quasi-static strain rates of 0.01, 0.1, and 1 s⁻¹ at −20 °C, 24 °C and 200 °C are considered. Tensile test results revealed the sensitivity of mechanical properties towards strain rate variations for considered temperatures. The key tensile properties, yield, and ultimate tensile stresses were positive strain rate dependent. However, Young’s modulus and elongation showed negative strain rate dependency. Experimental fracture toughness tests exhibited the lower Plane Strain Fracture Toughness (K_IC) at −20 °C compared to 24 °C. Elastic numerical fracture analysis revealed that the crack driving and constraint parameters are positive strain rate dependent and maximum at −20 °C, if plotted and analyzed over the stress ratio. The current results concerning strain rates and temperatures will help in understanding the performance-related issues of AA2050-T84 alloy reported in aircraft applications.     

Microstructure Evolution and Deformation Mechanisms of As-Cast Antibacterial Ti6Al4V-5Cu Alloy for Isothermal Forging Process

The hot workability behavior of antibacterial Ti6Al4V-5Cu alloy was investigated using a hot compression experiment in the temperature range of 790–1040 °C and strain rate of 10⁻³–10 s⁻¹ with a strain of 0.4. The deformation behavior of the alloy was characterized by Gleeble 3800 compression experiment, and the relationship among deformed microstructures and deformation parameters was established. The deformations of Ti6Al4V-5Cu alloy were temperature and strain rate-dependent. Higher temperature and lower strain rate made power dissipation efficiency (η) increase and reach 89%. The activation energies (Q) in the dual-phase (α + β) and single β phase regions were calculated as 175.43 and 159.03 kJ mol⁻¹, respectively. In the dual (α + β) phase region, with an increase in strain rate, flow-softening behavior was dominated, however in the single β phase region such as processing at 940 °C. Flow stress increased slightly in which work-hardening behavior was dominated (especially between strain rates of 10⁻³–1 s⁻¹). The deformation at various conditions exhibited different stress-strain profiles, providing an insight that work hardening and flow softening coexisted in Ti6Al4V-5Cu alloy. The relative intensity of oscillatory change in flow stress profile decreased as the strain rate decreased. The hot workability of Ti6Al4V-5Cu alloy was also accessed from the viewpoint of the sub-grain structure.