Low Strain Rates Research Articles

Quantification and assessment of the error associated with engineering stress-strain analysis in stress accelerated creep tests in 316H stainless steel

ABSTRACT Historically, reduction of area has been neglected during uniaxial creep tests, and engineering rather than true stress-strain and strain rate have been considered. In high load accelerated tests, there is an increasing error associated with the engineering stress and strain, hence this assumption is no longer valid. In this work, uniaxial creep tests on Type 316H austenitic stainless steel at 480–550 °C have been analysed for both engineering and true stress–strain and strain rate. Significantly higher stresses and lower minimum strain rates were determined from true stress-strain rate relationships for as-received 316H. These differences diminish as the material is strain hardened, limiting plastic loading strains and reducing creep ductility. The true stress-strain rate analysis method is shown to be more accurate, however, the engineering stress-strain analysis predicts higher creep strain rates for a given stress and is the more conservative measure for component lifetime assessments.

Hot processing map and high temperature deformation behaviour of TB17 Ti alloy

The thermal compression experiments of TB17 titanium alloy under different thermal deformation process parameters were carried out using a thermal simulation compressor. The high-temperature plastic flow behaviour of the alloy was studied. It was found that with the decrease of the deforming temperature and the increase of the strain rate, the flow stress increased, and the discontinuous yield phenomenon occurred in hot deformation. The larger the strain rate, the more obvious the discontinuous yield phenomenon. The thermal activation energy Q decreased with the increase of strain, and the average value of activation energy Q is 209.54 KJ / mol. The constitutive equation of high-temperature plastic flow of TB17 titanium alloy was established. The predicted values of this equation are in good agreement with the experimental values. The average error is 3.987 %, and the correlation coefficient is 0.9972, which has high accuracy. Based on the Prasad criterion, the hot processing map of TB17 titanium alloy was constructed. It was found that the flow instability zone was mainly concentrated in the high strain rate region. The flow instability zone was determined to be 795 °C ~ 895 °C, 0.046s-1 ~ 1s-1, and the stable deformation zone was mainly located in the region with high temperature and low strain rate. The optimum processing parameter range is 860 °C ~ 895 °C, 0.001 s-1 ~ 0.025 s-1.

From shear bands to earthquakes in a model granular material with contact aging.

We perform molecular dynamics simulations of homogeneous athermal systems of poly-disperse soft discs under shear. For purely repulsive interactions between particles, and under a confining external pressure, a monotonous flow curve (strain rate vs. stress) starting at a critical yield stress is obtained, with deformation distributing uniformly in the system, on average. Then we add a short range attractive contribution to the interaction potential that increases its intensity as particles remain in contact for a progressively longer time, mimicking an aging effect in the system. In this case the flow curve acquires a reentrant behavior, namely, a region where shear stress decreases with increasing strain. Within this region the deformation is seen to localize in a shear band with a well defined width that decreases as the global strain rate does. At very low strain rates the shear band becomes very thin and deformation acquires a prominent stick-slip behavior. This regime can be described as the system possessing a fault in which deformation occurs with an earthquake-resembling phenomenology. In this way the system we are analyzing connects a regime of uniform deformation at large strain rates, a localized deformation regime in the form of shear bands at intermediate stain rates, and seismic phenomena at very low strain rate. The unifying ingredient of this phenomenology is the existence of a reentrant flow curve, originating in the aging mechanisms present in the model.

Investigation on deformation behaviors and dynamic recrystallization mechanism of spray formed Al–Zn–Mg–Cu alloy under hot compression

The thermal deformation behavior of spray formed Al–Zn–Mg–Cu alloy was investigated by the isothermal hot compression tests at the strain rates of 0.001–10 s−1 with the temperature range of 350–450 °C. An Arrhenius constitutive equation was established by the corrected strain-stress curves, and then the processing map was constructed based on the 3D instability map and 3D power dissipation map. The influence of strain rate and temperature on both flow stress and dynamic softening has been unveiled. The results show that dynamic recovery (DRV) is the primary softening mechanism and dynamic recrystallization (DRX) is substantively retarded due to the fine dispersed particles uniformly distributed in the spray formed alloy. Continuous dynamic recrystallization (CDRX) is the primary DRX mechanism at a low temperature or high strain rate. DRX grain was observed at the grain boundaries, especially at the triple junctions. The appropriate thermal deformation condition is recommended at the temperature range from 430 °C to 450 °C and strain rates from 0.003 s−1 to 0.1 s−1.

Grain boundary plasticity in Mg binary alloys by segregation of p-block element

The effect of p-block elements (Ga, Ge and In) addition on grain boundary structures and room temperature mechanical responses was investigated on extruded Mg binary alloys with fine-grained structures. Grain boundary segregation was confirmed in the Mg–Ga and Mg–In alloys, whereas the Mg–Ge alloy did not show such microstructures associated with solubility. Grain boundary segregation affected the plastic deformation of the Mg–Ga and Mg–In alloys. In particular, the Mg–In alloy had a large strain rate dependency and exhibited good deformability at low strain rate regimens. First-principles calculations indicated that p-block elements produce a bond-weakening effect at grain boundaries, and atomistic distances at grain boundaries varies according to the element. Solute atom which brings about both bond-weakening and bond-expansion effects to Mg atoms is effective in enhancing the contribution of grain boundary sliding in deformation.

EFFECT OF PRELIMINARY DEFORMATION ON THE FORMATION OF ULTRAFINE-GRAINED STRUCTURE DURING EQUAL CHANNEL ANGULAR PRESSING OF MAGNESIUM ALLOYS

The formation of ultrafine-grained structure is very desirable in the microstructural design of magnesium alloys, in particular Mg-Zn-Ca medical alloy, for a substantial increase in their strength and corrosion resistance. However, conventional processing of these alloys by equal channel angular pressing is not easily applicable due to their low deformability, which often leads to rapid fracture of billets. In this paper, computer simulation data and principles of physical mesomechanics are used to demonstrate that preliminary deformation of Mg alloy billets by reduction at high temperatures and low strain rates significantly increases their deformation capacity and enables equal channel angular pressing at lower temperatures, resulting in billets with ultrafine-grained structure. Consideration is given to the physical nature of the established effect.

Study on design and impact energy absorption of Voronoi porous structure with tunable Poisson's ratio

As the inner core of crash box, the porous structure could cushion impact load through its own deformation. The aims of this study were to propose a series of Voronoi porous structures with tunable Poisson's ratio (VP-VPS) by using the periodic array of unit cells based on Voronoi-Tessellation and to develop crash boxes filled with porous structures for strong crashworthiness and high energy absorption. VP-VPS structures through the periodic arrays of unit cells were constructed according to 4 independent unit cell design factors. The quasi-static and dynamic compressive mechanical responses of VP-VPS structures prepared by selective laser melting (SLM) were studied through the combinations of mechanical test and simulation. Relationships between VP-VPS unit cell design factors and mechanical properties of structures were determined by establishing regression equations using the response surface method (RSM). Finally, the energy absorption of new crash boxes filled with VP-VPS structures was investigated through simulation. Results showed that VP-VPS structures had high load-bearing capacities and energy absorption under quasi-static and dynamic compressive conditions. Regression equations based on RSM could well predict mechanical properties of structures. The mechanical properties of VP-VPS structures were enhanced with the increase of global strain rate, which showed different deformation modes at low and high global strain rates. Compared with typical crash boxes filled with negative Poisson's ratio (NPR) inner cores, new type VP-VPS crash boxes had stronger impact resistance and higher energy absorption. This investigation provided a feasible design solution and theoretical basis for the construction and engineering application of impact resistance protective structures.

Complete constitutive model of CFRP including continuous damage in low strain rate compression and temperature generation in high strain rate impact

AbstractThis paper reports a method to construct the complete constitutive model of carbon fiber‐reinforced plastic (CFRP) by distinguishing the strain rate state and modifying the material stiffness. In quasistatic (low strain rate) compression, the initial nonlinear effect caused by the material defects was described by introducing an nonlinear increasing factor. In dynamic (high strain rate) impact, the nonlinear strengthening effect was described by introducing the dynamic amplification factors of stress and strain based on the reference state. Considering the instantaneous temperature rise obtained from the impact work–temperature generation equation and the influence of temperature on modulus and strength, the coupled thermomechanical constitutive models combining the strain rate effect and the temperature effect were established. The user‐defined material subroutines (VUMAT) were developed, and then these constitutive models were verified by finite element analysis (FEA). Finally, the developed material subroutine was applied to predict the impact penetration of CFRP laminates, and the results show that the opening holes, damage and energy dissipation are in good agreement with the reference experiment. This work comprehensively analyzed the construction method of CFRP constitutive models, which would provide a guidance for the coupled thermomechanical behavior under dynamic impact.Highlights An anisotropic continuum mechanical constitutive behavior considering strain rate effect and damage evolution behavior was established. A macroscopic anisotropic constitutive model including the coupled impact temperature generation‐mechanical behavior was established. Combined with the incremental finite element method, the three‐dimensional user‐defined material subroutines (VUMAT) were developed and verified. The thermomechanical impact penetration behaviors of CFRP laminates was predicted, and the stress field, temperature field and failure characteristics were visualized.

Experimental study on mechanical and acoustic emission characteristics of sedimentary sandstone under different loading rates

In the field of rock engineering, complexity of stress environment is an important factor affecting its stability. Thus, in view of fracture mechanism of rock under different loading rates within the scope of quasi-static strain rate, four groups of uniaxial compression tests with different strain rates were carried out on sandstone specimens, and strength, deformation, failure modes and acoustic emission characteristics of specimens were compared and analyzed. Furthermore, the fracture mechanism was discussed from the perspective of fracture characteristics based on fractal dimension, crack propagation law inverted through acoustic emission b-value, and micro fracture morphology. The results showed that as the strain rate increased from 10 to 5 s−1 to 10−2 s−1, the fractal dimension of rock fragments increased, and the fractal dimension of rock fragments increased by 9.66%, 7.32%, and 3.77% successively for every 10 times increase in strain rate, which means that the equivalent size of fragments was getting smaller, and the fragmentation feature was becoming increasingly prominent. The crack propagation process based on acoustic emission b-value showed that with the increase of loading rate, the specimen entered the rapid crack propagation stage earlier, in order of 68%, 66%, 29%, and 22% of peak stress. Moreover, the microscopic fracture morphology showed that with the increase of loading rate, transgranular phenomenon was clear, and the fracture morphology changed from smooth to rough. That meant that the fracture of sandstone rock at high loading rates was mainly caused by the propagation of large cracks, which was different from the slow process of initiation, convergence and re-propagation of small cracks at low strain rates.

Lath decomposition and dispersion induced by heterostructure deformation and associated interactions in a lamellae metastable-β Ti alloy during subtransus processing

The mechanisms of lath decomposition and dispersion were hitherto rarely explained due to limited understanding into the heterostructure deformation between two phases and associated interactions. In this work, the lath decomposition and dispersion were systematically investigated in a wide subtransus processing range of 0.001 s−1–1 s−1 and 745 °C–820 °C with the consideration into the heterostructure deformation and associated interactions. The relationship between flowing behavior and microstructure evolution were discussed. Results indicated that the initial buckling of α laths caused high peak strength. The rotation and twist of α laths are helpful to decrease the flow stress, but it caused serious extra deformation and dislocation storage in the β matrix. The lath decomposition dominated by the ablation was greatly contributed by the adiabatic temperature rise (ATR) near boundaries with high energies. The α laths could rotate under low strain rates, and numerous residual laths (RLs) could be obtained. The increment in strain rates to 0.1 s−1 resulted in earlier lath decomposition and softening, as well as to disperse αp particles and homogenize the β matrix. But an overhigh strain rate of ∼1 s−1 caused adiabatic shear bands. The low temperatures are unfavorable to the lath decomposition, while over-high temperatures diminished the extra deformation and ATR. On this basis, a deformation mechanism map for the subtransus processing of lamellae Ti-55531 alloy was established. This investigation sheds deeper insight into the tailoring of microstructure and prediction of flowing behavior for the subtransus processing of lamellae metastable-β Ti alloys.

Revealing the dynamic behavior and micromechanisms of enhancing the formability of AA1060 sheets under high strain rate deformation

Developing high strain rate (HSR) forming technologies is significant for efficient and high-quality aerospace sheet metal parts manufacturing. Research on the deformation behaviors and micromechanism of materials under HSRs will contribute to the further application of HSR forming technologies. In this study, the mechanical behavior of AA1060 pure aluminum at low strain rates (LSRs, 0.001 s−1 and 0.1 s−1) and high strain rates (HSRs, 2400 s−1 and 3300 s−1) was tested utilizing quasistatic tensile tests and Hopkinson bar tests at room temperature. The results of the mechanical properties showed that the elongations were 30.01 %, 37.91 %, and 46.61 %, corresponding to strain rates of 0.1 s−1, 2400 s−1, and 3300 s−1, respectively, which were 29.86 % at a strain rate of 0.001 s−1. The maximum amplification of AA1060 elongation reached 56.10 % at the HSR. Microstructure characteristics, including the Schmid factor distribution, geometrically necessary dislocation (GND) distribution, slip band, and dislocation cell, were observed by electron backscattering diffraction (EBSD) and transmission electron microscopy (TEM) under the condition of the same elongation with strain rates of 0.001 s−1 and 3300 s−1. In addition, the reasons for the plastic improvements during HSR loading were also investigated. The hard-oriented grains participate in plastic deformation at HSRs, providing additional space for dislocation multiplication and movement, increased dislocation density, and interaction between dislocations. In addition, the deformed hard-oriented grains also coordinated the strain gradient with soft-oriented grains. This improved the overall deformation uniformity, thus avoiding the premature occurrence of strain localization, namely, the elongation increase.

Nano-indentation deformation behavior of heavy ion irradiated reduced activation ferritic/martensitic (RAFM) steels

The Nano-indentation deformation behavior of the heavy ion irradiated RAFMs is investigated in the present work. Specimens of the CLF-1 steel were irradiated with 123.4 MeV 20Ne ion at both -50 °C and 400 °C, respectively, to achieve a mean displacement damage level of 0.15 dpa. A quasi-uniform distribution of the displacement damage was produced in the specimens by utilizing an energy degrader at the irradiation chamber. The results of nano-indentation experiments indicate that during the loading stage, the irradiated materials exhibit a lower strain rate, but during the holding stage after reaching the maximum load, the irradiated materials show a higher strain rate than the un-irradiated material. Transmission electron microscopy observation showed that the low-temperature irradiation produced a high density of irradiation-induced dislocation loops, which impeded the glide of dislocation lines during the loading stage. However, as the load increases gradually to the holding stage, the dislocation lines can overcome the pinning by the dislocation loops. The strain that did not occur due to the pinned effect of the dislocation loops in the loading stage was released during the holding stage, resulting in a higher strain rate in the irradiated specimen during the holding stage. Based on the Peierls mechanism, a quantitative relationship between the number density of the irradiation-induced dislocation loops and the strain rate during the holding stage was established. The calculated results agree well with the experimentally obtained strain rate during the holding stage.

Investigation of the Hot Deformation Behavior and Mechanism of a Medium-Entropy CoCr0.4NiSi0.3 Alloy

The CoCrNi-based medium-entropy alloys (MEA) have been extensively investigated due to their exceptional mechanical properties at both room and cryogenic temperatures. To investigate the hot deformation behavior and the recrystallization mechanism of the CoCr0.4NiSi0.3 medium-entropy alloy, a series of deformation tests was conducted using the MMS-100 thermal simulation tester, with deformation conditions of 0.001–1 s−1/850–1150 °C. During the hot deformation process, the flow stress initially increases up to its peak value before gradually decreasing towards a steady state level. Higher flow stress levels are observed with increasing strain rate and decreasing deformation temperature. The estimated activation energy for hot deformation of this alloy is approximately 423.6602 kJ/mol. The Arrhenius-type constitutive equation is utilized to establish a modified model while incorporating power dissipation theory and the instability criterion of a dynamic material model to construct power dissipation maps and instability maps. By superimposing these maps, hot processing maps with strains of 0.4, 0.5, and 0.7 are derived. In this investigation, it is observed that regions of instability exclusively occur when the true strain exceeds 0.4. These regions of instability on the hot processing map align well with experimental findings. The suitable range of parameters for hot-working decreases as the true strain increases. The microstructure was analyzed using electron backscatter diffraction and transmission electron microscopy (TEM) techniques. The volume fraction of dynamic recrystallization (DRX) decreases with increasing strain rate but diminishes with rising temperature. The TEM characterization elucidated the mechanism of DRX in this MEA. The presence of the long-period stacking ordered (LPSO) phase was observed in both the face-centered cubic matrix and hexagonal close-packed recrystallized grains under different deformation conditions. The LPSO phase originates from the matrix at a low strain rate, whereas it is generated during recrystallization at a high strain rate. The observed increase in flow stress of the as-cast MEA is primarily attributed to the synergistic effects arising from the interaction of the dislocation with twins and the second phase. The onset of instability is effectively suppressed within a limited range through the formation of coherent second phases such as L12, LPSO, and superlattice structures resulting from phase transitions. These second phases serve as nucleation sites for recrystallization and contribute to the strengthening of dispersion. Furthermore, their interaction with dislocations and twins significantly influences both flow stress behavior and recrystallization kinetics under hot deformation. These findings not only deepen our understanding of the underlying deformation mechanisms governing MEA but also offer valuable insights for designing CoCrNi-based alloys with improved mechanical properties at elevated temperatures.

A constitutive model incorporating the interplay of dynamic recrystallization and twinning during hot deformation of AZ31 magnesium alloy

Dynamic recrystallization (DRX) and deformation twinning play a pivotal role in stress partitioning during hot deformation of magnesium alloy. However, the influence of twinning on stress is diverse, and the interaction between DRX and twinning is intricate. Existing constitutive models cannot simultaneously describe the relationship between DRX and twinning, as well as their effects on stress. In this study, the hot compression tests were conducted to study the flow behavior and microstructure evolution of AZ31. The obtained flow curves and microstructure revealed that AZ31 alloy undergoes simultaneously DRX softening and twinning hardening during hot deformation. Furthermore, texture evolution was significantly influenced by both DRX and twinning behaviors. As a result of DRX behavior, there was a decrease in twin volume fraction in the later stages of deformation. Consequently, a twin volume fraction model that incorporates the inhibitory effect of DRX was proposed. According to the experimental results of high temperatures and low strain rates, a constitutive model incorporating work hardening, dynamic recovery (DRV), and DRX was established. Additionally, the influence of twinning on flow stress was incorporated into the model, resulting in a constitutive model that considers both DRX and twinning simultaneously. Finally, the proposed model's reliability was validated through the wedging spinning process, successfully predicting both macroscopic deformation and microstructure evolution of the spinning parts.

Analysis of super Cr13 stainless-steel internal fracture growth effects during skew mill piercing process

The seamless tube piercing process of super Cr13 martensitic stainless steel is addressed in this paper by comparing industrial piercing tests, laboratory hot tensile tests for material behavior characterization, and finite element simulations. Particular focus is given to the effect of process parameters on internal fracture growth and geometrical homogeneity of the tube. The geometrical non-homogeneities found on industrial pierced tubes are closely related to the change of flow stress of super Cr13 stainless steel during the piercing process. This way, the non-uniform strain rate along the tube's cross-section during piercing affects the fracture growth and, consequently, the thickness homogeneity of the tube, which varies from tip to tail. Due to obtained results, the mean value of pierced tube perimeter is 660 mm, while the mean value of the tube perimeter in the FEM simulation was predicted to be 2 % more (675 mm). The contact temperature of the plug and piercing tube was predicted at 1100 °C, and the mean value of pierced tube diameter in the simulation (210 mm) was 1.5 % more than the mean value of the actual tube (207 mm). The morphology of δ-ferrite affects the origin of primary crack initiation during the piercing process. Short and thick grains of δ-ferrite created at low strain rates that lengthen with increasing strain rate affect fracture sensitivity at the tip of the plug, favoring the non-homogeneity of the material.

Mechanical properties of graphene-mortar at high strain rates

Graphene has been considerably studied as a reinforcing nanomaterial in cementitious composites to improve their mechanical properties under quasi-static loading. However, there is still lack of knowledge in graphene cementitious composites under high strain rate loadings. This paper reports the reinforcing effect of graphene on the mechanical behaviour of mortar at high strain rates. Different graphene contents were incorporated into the mortar to study their effect on the behaviour of mortar quasi-statically and dynamically. Compressive and split tensile strengths were measured under low and high strain rates using a universal testing machine and split-Hopkinson pressure bar (SHPB), respectively. It was found that adding 0.05% and 0.01% of graphene to the mortar enhanced the dynamic compressive and split tensile strengths up to 30% and 9.5% at 175 s-1 and 2–5 s-1 strain rates, respectively. Moreover, to understand the macroscale mechanical behaviour of the graphene mortar, Scanning Electron Microscopy (SEM), Energy Dispersive Spectrometer (EDS) and Mercury Intrusion Porosimeter (MIP) were employed to explore the morphology, porosity and hydration products of graphene mortar. The results indicated that graphene acted to fill the voids as well as to impede the crack path.

Characterizing piezoelectric properties of PVDF film under extreme loadings

Polyvinylidene fluoride (PVDF) as a polymer has been proven to be an effective piezoelectric sensor with advantages of good flexibility, high mechanical strength, and high chemical resistance. Numerous studies have focused on the response of PVDF film at high strain rates, but few on low strain rate response, and the response of PVDF film at different strain rates is unknown. To address these limitations, we examine the piezoelectric properties of PVDF film at extreme high and low loading rates. We design quasi-static compression and dynamic split Hopkinson pressure bar (SHPB) test setups to examine the response of PVDF film. Quasi-static compression test results show that PVDF films have good repeatability and linearity. The charge shift phenomenon is observed at quasi-static loading conditions, and the charge shift rate is found to be related to the gain coefficient of charge amplifier. Next, SHPB tests are performed and results show that PVDF film can well capture the propagation of stress wave. Moreover, it is observed that the PVDF film under high loading rate has a higher failure strength in comparison to that of low loading rate. Finally, based on the measured points by quasi-static compression and SHPB tests, the piezoelectric coefficients of PVDF film under extreme low (on the scale of strain rate of 10−2 s−1) and extreme high (on the scale of strain rate 105 s−1) loading rates are found to be 30.79 pC/N and 27.72 pC/N, respectively. Note that, the strain rate difference is seven orders of magnitude, the piezoelectric coefficient difference is only 9.97%. We believe our findings can advance the design and application of PVDF films in practical engineering.

{332}[formula omitted] twinning in a [formula omitted]-type Ti-Nb alloy over a wide range of strain rates

The {332}〈113〉 twinning in a β-type Ti-25Nb alloy is investigated quantitatively at 10% compression strain over a wide range of strain rate from 10−2 s−1 to 106 s−1, using material testing system, split Hopkinson pressure bar, and gas gun loading. Electron backscatter diffraction data are collected from the postmortem samples to obtain activated twinning systems and twinning strain tensors. With increasing strain rate, yield stress and twin density increase, and twin thickness decreases. At low strain rate, only the twinning systems with high Schmid factor can be activated to form thick twins. However, at medium and high strain rates, certain twinning activation deviates from the Schmid law, and twin thickening is relatively insensitive to Schmid factor. Twinning strain is the highest for the matrix grain orientations near 〈114〉, but approximately zero for the orientations near 〈111〉. Contribution of twinning to plastic strain at medium strain rate is significantly higher than those at low and high strain rates.

Discontinous and continuous dynamic recrystallization of Fe-12.5Cr–4Al–2Mo-0.03Nb-0.08Y alloy during hot deformation

The hot deformation behavior and microstructure of Fe-12.5Cr–4Al–2Mo-0.03Nb-0.08Y alloy were studied under conditions of 800 °C–1200 °C/0.01 s−1∼10 s−1 using a combination of hot compression experiments, EBSD and TEM characterization. The results indicate that the deformation temperature and strain rate have a significant impact on the flow stress and microstructure of the alloy, especially the deformation temperature. The constitutive equation constructed in this paper can reflect the hot deformation process and accurately calculate flow stress value of the FeCrAl alloy in corresponding states. The FeCrAl alloy undergoes DRV and DRX during hot deformation. DDRX grains distributed along the original grain boundaries mainly formed at low deformation temperatures and high strain rates, while CDRX grains mainly formed at high deformation temperatures and low strain rates and characterized by the internal distribution of the original grains. Moreover, the orientation of DDRX grains is mostly different from that of adjacent original grains, while the orientation of CDRX grains is relatively close to that of the original grains.

Evaluation of constitutive equations for modeling and characterization of microstructure during hot deformation of sintered Al–Zn–Mg alloy

Commercial simulation software like QFORM and DEFORM do not possess adequate material data for alloys produced through powder metallurgy. Therefore, in the present study, hot compression tests of Al-5.6%Zn–2%Mg aluminum alloy were conducted at temperature ranges (300 0C-500 °C) and strain rates (0.1 s−1-0.0001 s−1). The impact of compression temperature and strain rate on the flow curve behaviour and microstructure evolution-associated mechanisms were investigated through experimentally acquired flow curves and EBSD analysis. Four constitutive models were constructed; namely the Arrhenius-type, modified Johnson Cook (MJC), modified Zerilli-Armstrong (MZA), and an artificial neural network (ANN). The results demonstrated that among the models considered, the ANN and Arrhenius-type models exhibited the lowest AARE values of 0.486 % and 3.36 %, respectively. Conversely, the MZA and MJC models displayed higher AARE values of 8.84 % and 3.93 %, respectively. Notably, the Arrhenius-type model emerged as the most suitable prediction model due to its capability to handle nonlinear relationships between factors. However, in scenarios where material properties are unknown or experimental data is limited, the MJC model can serve as a simpler alternative. The MZA model was deemed unsuitable for accurately estimating flow stress in hot compression. Remarkably, the best-trained ANN model exhibited the highest predictive performance with an AARE of 0.486 % and an R-value of 0.99. This study offers fundamental insights to improve the accuracy of simulating hot compression procedures. EBSD analysis demonstrated that higher upsetting temperatures and lower strain rates promoted recrystallization, resulting in a more uniform microstructure.