Deformation Strain Rate Research Articles

Study on thermal compression deformation behavior and constitutive model of homogenized Mg–5Zn–1Mn alloy

The thermal compression deformation behavior of homogenized Mg–5Zn–1Mn (wt.%) alloy was systematically investigated over the temperature and strain rate ranges of 285–345 °C and 0.001–1 s−1, respectively. The constitutive model and thermal processing diagrams were established. The microstructure evolution process and dynamic recrystallization (DRX) mechanisms were analyzed. The results demonstrate that the flow stress curves of the ZM51 alloy exhibit prominent DRX characteristics. The peak stress can be improved by decreasing the deformation temperature or increasing the strain rate. A finite element simulation is performed, and the Arrhenius constitutive model can accurately depict the plastic flow process of the alloy with strain correction, and the average activation energy is about 143.821 kJ/mol. Both the percentage DRX and the DRX grain size are found to be sensitive to the applied deformation conditions, including temperature, strain rate, and true strain. The formation of DRX grains promotes the weakness of the texture and the refinement of the grains. Grain boundaries nucleation (including discontinuous and continuous DRX) and particle-stimulated nucleation (PSN) are the main DRX mechanisms. Based on the processing map, ZM51 alloy is suitable for large plastic deformation by multi-pass forging. The optimum processing temperature is 345 °C, and as the degree of plastic deformation increases, the strain rate can be suitably increased. Local plastic flow and microcracking at grain boundaries are the primary instability mechanisms of the alloy.

Classical and machine learning interatomic potentials for BCC vanadium

BCC transition metals (TMs) exhibit complex temperature and strain-rate dependent plastic deformation behavior controlled by individual crystal lattice defects. Classical empirical and semiempirical interatomic potentials have limited capability in modeling defect properties such as the screw dislocation core structures and Peierls barriers in the BCC structure. Machine learning (ML) potentials, trained on DFT-based datasets, have shown some successes in reproducing dislocation core properties. However, in group VB TMs, the most widely used DFT functionals produce erroneous shear moduli ${C}_{44}$ which are undesirably transferred to machine-learning interatomic potentials, leaving current ML approaches unsuitable for this important class of metals and alloys. Here, we develop two interatomic potentials for BCC vanadium (V) based on (i) an extension of the partial electron density and screening parameter in the classical semiempirical modified embedded-atom method (XMEAM-V) and (ii) a recent hybrid descriptor in the ML Deep Potential framework (DP-HYB-V). We describe distinct features in these two disparate approaches, including their dataset generation, training procedure, weakness and strength in modeling lattice and defect properties in BCC V. Both XMEAM-V and DP-HYB-V reproduce a broad range of defect properties (vacancy, self-interstitials, surface, dislocation) relevant to plastic deformation and fracture. In particular, XMEAM-V reproduces nearly all mechanical and thermodynamic properties at DFT accuracies and with ${C}_{44}$ near the experimental value. XMEAM-V also naturally exhibits the anomalous slip at 77 K widely observed in group VB and VIB TMs and outperforms all existing, publically available interatomic potentials for V. The XMEAM thus provides a practical path to developing accurate and efficient interatomic potentials for nonmagnetic BCC TMs and possibly multiprincipal element TM alloys.

Strain Hardening Exponent and Strain Rate Sensitivity Exponent of Cast AZ31B Magnesium Alloy

The flow curves of as-cast AZ31B magnesium alloy during high temperature deformation were obtained with a thermal compression test, and the effects of deformation amount, grain size, strain rate, and deformation temperature on the flow stress, strain rate sensitivity index, and strain hardening index were analyzed. The results showed that deformation and grain size were negatively correlated with both the strain rate sensitivity index and strain hardening index. The increase in strain rate increased the strain hardening index but made the strain rate sensitivity index show an opposite trend. Increasing temperature reduced the strain rate sensitivity index and strain hardening index but, when the temperature exceeded 700 K, the strain rate sensitivity index was no longer affected by temperature. Since the strain rate sensitivity index m and strain hardening index n are important parameters for measuring the plastic deformation of metal materials, this study has great significance for guiding the selection of process parameters in the plastic processing of as-cast AZ31 magnesium alloy.

Limiting oxidation of high entropy alloy via high strain-rate deformation: Insights from electrochemical impedance spectroscopy

Material processing is often performed to form a fine grain structure with uniform distribution of mechanical properties. In the present study, a one-step solid phase processing technique that take advantage of in-situ reactive metallurgy, called stationary friction processing (SFP), is proposed to improve high temperature oxidation performance of AlCoCrFeNi high entropy alloy (HEA). The strategy involves producing a multi-phase fine-grain microstructure through SFP. The processed specimen retarded the oxidation kinetics by ∼52%. The electrochemical impedance spectroscopy coupled with transmission electron microscopy provided new insights into the physico-chemical nature and performance of the oxide-scale. Processed specimen demonstrated an increase in the polarization resistance with the immersion time while unprocessed HEA showed the reverse trend. The excellent oxidation performance was attributed to thin, adherent and uniform oxide layer on the processed HEA.

Hot workability and microstructural evolution of a nickel-based superalloy fabricated by laser-based directed energy deposition

Recently, an innovative process chain has been investigated and proposed, using laser-based directed energy deposition technology to produce pre-forms for forging. The advantage of this technology is to get high-performance near-formed parts at a low cost, compared traditional processing. Clarifying the hot workability and the microstructural evolution of as-deposited samples is the key to obtaining high performance parts. In present work, the plastic behaviors and dynamic recrystallization mechanisms of as-deposited nickel-based superalloy are studied. The compression curves are corrected by eliminating adiabatic heating and friction effect. And then the hot deformation activation energy and the constitutive equation of as-deposited sample are obtained. Compared to the wrought Inconel 625, as-deposited Inconel 625 has lower hot deformation activation energy (466.511 kJ/mol). The peak stress gradually decreases, while the recrystallized grain volume fraction gradually increases when deformation temperature increases and strain rate decreases. The characterization results of TEM and EBSD show that the discontinuous dynamic recrystallization mechanism nucleating by the bowing of grain boundaries occupies an absolute dominant position. In addition, combined with the microstructural evolution and hot processing map, the best hot working conditions of as-deposited Inconel 625 are obtained (deformation temperature: 1050–1150 ℃, strain rate: 0.001–0.01 s−1).

Revealing Crustal Deformation and Strain Rate in Taiwan Using InSAR and GNSS

AbstractInterseismic deformation describes the gradual accumulation of crustal strain within the tectonic plate and along the plate boundaries before the sudden release as earthquakes. In this study, we use 5 years of high spatial and temporal geodetic measurements, including Global Navigation Satellite System and Interferometric Synthetic Aperture Radar to monitor 3‐dimension interseismic crustal deformation and horizontal strain rate in Taiwan. We find significant deformation (strain rate >8 10−6 yr−1) along the plate boundary between the Philippine Sea and the Eurasian Plates in east Taiwan. The high strain rate in the southern part of the Western Foothills is distributed along a few major fault systems, which reveals the geometry of the deformation front in west Taiwan. Our results help identify active faults in southwest and north Taiwan that were not identified before. These findings can be insightful in informing future seismic hazard models.

In Situ Strain Measurements Within Helmet Padding During Linear Impact Testing.

Drop and Impact testing of helmets are used extensively in the design process and eventual certification of helmets. These techniques have traditionally relied heavily on the measurement of the kinematic response to impact, which provides an indirect measurement of the liner response that is subject to interpretation during the design process. In the present work, we introduce an in situ experimental technique that provides a time-resolved measurement of the deformation of the helmet and its components during an impact event. The data collected from a high-speed X-ray imaging system can provide a full description of the deformation at the component level, which provides a helmet designer further insight into the performance of their helmet, while also returning the traditional kinematic metrics. The data presented focuses on the deformation of a commercial hockey helmet subjected to a series of linear impacts with three different impactor caps at speeds ranging from 2.4 to 4.5m/s. Deformation of the liner was monitored in the midsagittal and a parasagittal plane of the helmet. The results show that there is a clear dependence on the maximum strain achieved in the foam that is dependent on the impact type, the impactor shape, and the resulting strain rate of deformation in the foam liner. These techniques can provide the first data for a direct validation and calibration of finite element helmet deformation models, while also providing a new tool-set to improve the efficacy of helmet design.

Deformation mechanisms of primary γ′ precipitates in nickel-based superalloy

Coarse γ′ precipitates with ordered structure (i.e. primary γ′ precipitates) residing on grain boundaries in nickel-based superalloys are generally considered to be non-deformable, they are thus being tailored to restrict grain growth during hot deformation. We demonstrate here, using both transmission electron microscopy analysis and molecular dynamics simulation, that deformation actually occurred on these precipitates and it is dominated by 1/6 <112> Shockley partial dislocation shear mechanism. Molecular dynamics simulations further reveal that all the critical strains triggering plastic deformation of primary γ′ under uniaxial tensile test are identically very low, depending on the deformation temperatures and strain rates. These findings provide new insight into the precise control of microstructure in nickel-based superalloy containing grain boundary precipitates.

Hot Deformation Behavior and Processing Maps of ZnSnO3/Cu Composites.

In this work, we designed ternary ZnSnO3 particle-reinforced Cu matrix composites and evaluated the hot deformation behavior of ZnSnO3/Cu composites. The hot deformation characteristics of typical dynamic recrystallization were probed by the resulting true stress–strain curves of ZnSnO3/Cu composites. The influences of deformation conditions, including temperatures (650–850 °C) and strain rates (0.01–5 s−1), on the flow stress of the designed composites were investigated. This revealed that the peak stress increased with the increasing of strain rate and decreasing of temperature. Additionally, the activation energy was calculated to be 237.05 kJ/mol and followed by yielding a constitutive equation for low-stress ZnSnO3/Cu composites. The processing maps established by dynamic materials model theory indicated that the designed composites possessed excellent hot workability, and then the processing parameters (790–850 °C and 0.01–0.04 s−1) of the ZnSnO3/Cu composites were determined for practical industrial production. Our work discloses the deformation behavior of ZnSnO3/Cu matrix composites and extends the rational process design for ternary ceramic/metal materials with excellent hot workability.

High temperature flow behavior and deformation mechanism of Nb-22.5Cr-2.5Mo alloy

The high temperature compression is performed by isothermal compression tests using Gleeble 3500 thermo-mechanical simulator at a constant strain rate for the hot-pressed Nb-22.5Cr-2.5Mo alloy. The deformation temperature ranges from 800 to 1200 °C and the strain rate ranges from 0.001 to 0.1 s−1. The high temperature flow behavior and deformation mechanism of the alloy are investigated based on the compression test data and TEM observation of the deformed microstructure. The results show that the ductile–brittle transition temperature of the alloy is about 800 °C, and the flow stress is sensitive to the deformation temperature and strain rate, in which the plastic deformation ability increases obviously with the increase of deformation temperature and the decrease of strain rate. Besides, the hyperbolic sine Arrhenius model with stress exponent of 3.131 and apparent activation energy of 402 kJ/mol is established for the peak flow stress. The value of apparent activation energy is higher than that of Nb metal (246 kJ/mol), which implies the existence of Laves phase NbCr2 makes the deformation of the alloy more difficult. Moreover, it is found that the deformation mechanisms in the Nbss matrix are mainly DRV controlled by the glide and climb of the dislocations and DRX formed by bulging nucleation mechanism, while the deformation mechanisms in the Laves phase NbCr2 particles are mainly twinning and synchroshear of the Shockley partial dislocation.

Micro-laminated CoCrFeMnNi−TiNp/CoCrFeMnNi high-entropy alloy matrix composite with bimodal grain structure via multi-material selective laser melting (MM-SLM) additive manufacturing

Deviating from most studies on selective laser melting (SLM) additively manufactured single metals or homogeneous metal matrix composites (MMCs), this work engaged in a multi-material SLM (MM-SLM) route for micro-laminated MMCs with bimodal grain structures. Structurally hierarchical micro-laminate of CoCrFeMnNi high-entropy alloy (HEA)-based HEA−TiNp/HEA MMC was built by the MM-SLM to overcome the strength-ductility trade-off and improve the anti-impact performance under high strain-rate compression deformation. The dynamic impacts were performed on the SLM-built HEA and MM-SLM-built HEA−TiNp/HEA using a split Hopkinson pressure bar (SHPB) system, with the strain rates of 1000 s−1, 2000 s−1, and 3000 s−1. The structurally hierarchical HEA−TiNp/HEA exhibited higher strength and deformability than the HEA. The strain-rate-dependent work hardening capacity and macroscopic plasticity of the HEA−TiNp/HEA indicated a better resistance to dynamic shocks. The promising results pave a road for achieving high-performance HEA-based MMCs of the MM-SLM-built hierarchical structures with a relatively low proportion of nano-ceramic reinforcements and bimodal-grained HEA matrix.

Mechanical behavior and shear band of a powder-metallurgy-fabricated CoCrFeMnNi high-entropy alloy during high strain-rate deformation

High-entropy alloys (HEAs) fabricated by powder metallurgy are considered to exhibit extremely-great potential application values in the field for high-speed impact deformation due to their uniform microstructures and compositions. The mechanical behavior of a powder-metallurgy-fabricated (PM) CoCrFeMnNi HEA was investigated at room temperature with strain rates ranging from 1200 s−1 to 2800 s−1. It was found that the serration behavior and shear localization of the alloy under dynamic conditions occurred. Results also indicated that the serrated flow took place in the PM CoCrFeMnNi HEA during mechanical deformation at high strain rates (>1000 s−1) and became more pronounced as the strain rate increased. Furthermore, it was determined that the yield-strength values of the PM CoCrFeMnNi HEA were sensitive to strain rates, where the values increased from 500 MPa to 700 MPa when the strain rates increased from 1200 s−1 to 2800 s−1. Shear bands with a width of about 20 μm were generated in the PM CoCrFeMnNi HEA after the shear stress reached a maximum value of 635 MPa, which corresponded to a nominal strain of about 8.71. Nanotwins and ultrafine-equiaxed grains with a diameter of about 150 nm also developed at the core of the shear band during deformation. The results revealed that the strength of the shear band was much higher than that of the matrix grain. Nanotwins in the shear band were composed of a single face-centered-cubic (FCC) structure with the twin plane of (1¯11¯), which could be formed via a rotational dynamic recrystallization (RDR).

Investigation of High-Temperature Constitutive Behavior of Ti555211 Titanium Alloy Subjected to Plastic Deformation in the Different Phase Regions

Ti555211 titanium alloy is subjected to plastic deformation in the dual-phase (α + β phase) zone and single-phase (β phase) zone at various deformation temperatures and strain rates. High-temperature constitutive equations of the alloy in the dual-phase zone and single-phase zone are established in order to describe deformation behavior of the alloy in the different phase zones. By comparing the constitutive equation of the alloy in the dual-phase zone with that of the alloy in the single-phase zone, the deformation activation energy of the former was found to be higher than that of the latter. It is obvious that the deformation activation energy of α phase is obviously greater than that of β phase. Furthermore, the microstructural evolution of the alloy is different in the dual-phase zone and single-phase zone. When the alloy was subjected to plastic deformation in the dual-phase zone, the size of the grains in the β phase increased with the decreasing strain rate. When the alloy was subjected to plastic deformation in the single-phase zone, the size of the grains in the β phase considerably increased with the increasing deformation temperature. In particular, in the microstructures of the alloy subjected to plastic deformation in the single-phase region, the elongated grains can be observed at higher strain rates. Furthermore, it is more difficult for the alloy to induce plastic deformation in the dual-phase region than in the single-phase region.

High temperature and strain-rate response of AA2124-SiC metal matrix composites

This paper presents the results of the study of the dynamic impact behaviour of the AA2124-SiC Metal Matrix Composite (MMC) material with different particle reinforcement sizes and qualities using a compressive Split-Hopkinson Pressure Bar (SHPB) apparatus. Mechanical tests were performed at strain rates 1000 s−1, 2000 s−1, and 3000 s−1 and at temperatures of room temperature (25 °C), 100 °C and 200 °C. Microstructural analyses were carried out on the samples pre and post-compression experiments to study the fracture characteristics and mechanisms of the MMC materials. The flow stress-strain, strain rate, temperature effects and deformation mechanism were investigated. The backscattered electron images show that a higher strain rate of deformation induces the formation of denser and smaller grain size of CuAl2 precipitates, especially in composites with smaller SiC particle sizes. Temperature has posed a minor effect on the microstructural change. Heating the samples close to a solution treatment temperature, and then followed by an air quenching has resulted in a fine dispersion of CuAl2 precipitates, as well as a high saturation for the materials with a higher volumetric fraction of SiC reinforcement. The SHPB compression results reveal that the 225XF material has developed the highest stress among all materials. For materials with a higher volumetric fraction of SiC reinforcement (225XE and 225XF), cracks and failures have appeared in the samples during high strain rate and high-temperature compression experiments, which is believed to be caused by the increased brittleness of the material as a result of intensified oxide phases.

Deformation behaviour and strain rate sensitivity of 304L SS at elevated temperatures

ABSTRACT Tensile deformation behaviour of nuclear grade 304 L SS (PHWR calandria vessel material) was presented at temperatures 300 K to 1123 K and at three different strain rates. The deformation behaviour is influenced by the strain-induced martensitic transformation at 300 K, the occurrence of dynamic strain ageing (DSA) at intermediate temperatures (573–873 K) and the dominance of strain softening at high temperatures (973–1123 K). The occurrence of DSA caused anomalies in flow behaviour and ductility for the steel. At high temperatures, strain softening manifested in a rapid decrease in flow strength with increasing temperature and decreasing strain rate. Further, instantaneous (mi) and quasi-steady state strain rate sensitivity (ms) with strain were evaluated using strain rate jump tests. At low and DSA temperatures, the initial and quasi-steady transient response differs. Contrary to this, the value of mi is equal to ms at high temperatures.

On the Mechanical Response of Aluminum Alloy 6061-T6 under Extreme Strains and Strain Rates, and Rapid Heating

The flow stress of aluminum alloy 6061-T6 produced by conventional thermomechanical methods has been investigated under the application of strains up to 80% at a strain rate of the order of 50001/s, and temperatures ranging from ambient to near melting. The high strain and strain rate deformation was imposed using a Kolsky bar compression apparatus equipped with a fast pulse-current heating system to reach the target temperatures at high heating rates. The flow stress was measured under strains, strain rates, temperatures and heating rates that match thermomechanical conditions developed in the primary shear zone of a specially designed machining with chip pulling test method. Flow stress error is estimated by statistics obtained from experimental replicates. It is expected that these measurements will enable the formulation of realistic machining models for Al6061-T6. Temperature measurements were obtained using non-contact infrared (IR) full field imaging together with embedded micro-thermocouple (TC) point probing. The TC measurements were used to estimate the emissivity of the aluminum specimen via separate, in situ calibration tests, and to track temperature evolution during the compression, also via separate testing, not compromising the flow stress measurements. Type-K TC measurements were made using the separated junction principle by embedding the TC wires into two micromachined holes in the specimen. The temperature measurement technique is discussed in detail, and temperature uncertainties are estimated. The Kolsky bar and machining test with chip pulling will be used going forward to study the effect of heating time on the dynamic thermal softening behavior of Al6061-T6, which has been shown to be time-sensitive under quasi-static loading when temperatures exceed 200°C, due to Mg-Si precipitate growth.

Dynamic recrystallization behavior and numerical simulation of S280 ultra-high strength stainless steel

The S280 ultra-high strength stainless steel was subjected to isothermal constant strain rate compression experiments under the conditions of deformation temperature 1000–1150 °C and strain rate 0.001–10 s−1 by Thermecmaster-Z thermal simulation testing machine. The flow behavior of S280 ultra-high strength stainless steel was analyzed; the dynamic recrystallization critical strain model, dynamic recrystallization volume fraction model, dynamic recrystallization grain size and average grain size model of the steel were established, and its dynamic recrystallization behavior was numerically simulated. The results show that the flow stress of S280 ultra-high strength stainless steel increases with the increase of strain rate and the decrease of deformation temperature. The distribution of dynamic recrystallization volume fraction and average grain size in each deformation region after thermal compression is not uniform, and the dynamic recrystallization volume fraction increases with the increase of deformation temperature and decrease of strain rate; the average grain size increases with the increase of deformation temperature and strain rate. The numerical simulation results are in good agreement with the experimental results, which can provide a theoretical basis for the microstructure control of the steel during thermal deformation.

Failure behaviors and processing maps with failure domains for hot compression of a powder metallurgy Ni-based superalloy

Processing maps are key to guiding the thermo-mechanical processing (TMP) of superalloys. However, traditional processing maps are incapable of delimiting failure, which is an essential factor to be concerned about during the TMP of superalloys. Employing isothermal hot compression experiments and finite element analysis (FEA), the present study examined the failure behaviors of a powder metallurgy (P/M) Ni-based superalloy and constructed processing maps with failure domains based on the predicted failure threshold. The micromechanical Gurson-Tvergaard-Needleman (GTN) damage model was employed in the FEA to model the cavity-driven intergranular fracture of the superalloy. Deformation temperature and strain rate were considered in the range of 1050–1150 °C and 0.001–1 s−1, respectively. The FEA results reveal that the maximum tensile stress locates at the outer budging surfaces of the samples, which causes failure initiation and subsequent propagation into longitudinal cracks, being consistent with the experiments. It is further demonstrated that the failure is strain-controlled and the critical failure strain remains nearly insensitive to the range of strain rates considered while increasing with the increase of temperature in a third-order polynomial. Finally, an optimized processing window for hot deformation of the superalloy is formulated to warrant good hot workability while avoiding flow instability and failure. The present study offers direct insights into the failure behaviors of P/M Ni-based superalloys and details a modeling strategy to delineate optimized parametric spaces for the TMP of superalloys.

Dynamic recrystallization behavior of a Mo-2.0%ZrO2 alloy during hot deformation

The high-temperature deformation process of molybdenum alloy reinforced by 2.0%ZrO2 was tested in the temperature range of 1100–1400 °C and strain rate range of 0.005–1 s−1 in a vacuum environment, and the microstructure evolution during the high-temperature deformation process was investigated. Based on the Arrhenius model, the transient equation of the Mo-2.0%ZrO2 alloy was established, and the relationship between deformation temperature, strain rate and flow stresses was described. The flow stresses of the Mo-2.0%ZrO2 alloy were characterized by dynamic recovery and recrystallization in the deformation process. Dynamic recrystallization of the Mo-2.0%ZrO2 alloy mostly occurs at high temperatures and low strain rates. At higher strain rates (0.1–1 s−1) and low temperatures (1100–1200 °C), chain-like fine crystals and fine equiaxed grains were found, indicating that partial dynamic recrystallization occurred. At low strain (0.005 s−1) and low temperatures (1100–1200 °C), equiaxed grains were found to demonstrate continuous dynamic recrystallization. Coarse equiaxed grains were found at low strain (0.005–0.1 s−1) and high temperature (1300–1400 °C), indicating a dominance of grain growth. The Mo-2.0%ZrO2 alloy have low activation energy compared with Mo-Al2O3 alloy, which is beneficial to hot working. The Mo-2.0%ZrO2 alloy has two typical textures, 〈100〉//ND and 〈111〉//ND, after high temperature deformation. As the strain decreases, there is enough kinetic energy to reduce the basal plane deviation in TD and RD directions, and the texture of Mo-2.0%ZrO2 alloy is dominated by 〈100〉//ND.

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 (ln = −4.6–−1.8).