High Strain Rate Research Articles

Investigations of the Progressive Damage and Failure Behaviors of Thermally Treated Granite Under the Coupling Action of Biaxial Stress Constraint and High Strain Rate

Investigations of the Progressive Damage and Failure Behaviors of Thermally Treated Granite Under the Coupling Action of Biaxial Stress Constraint and High Strain Rate

Modelling a Response of Complex-Phase Steel at High Strain Rates

In this article, a response of the complex-phase high-strength steel SZBS800 was modelled by considering the strain-rate influence. The material’s response was first measured with a series of standard tensile tests at lower strain rates. Higher strain rates were achieved using the unconventional test of shooting the ball into flat specimens. A viscoplastic formulation of the Cowper–Symonds material model was applied to consider the strain-rate effects. The parameters SIGY, p, and C of the material model were estimated using a step-wise procedure. First, rough estimates of the three parameters were obtained from the tensile tests using the grid search method. Then, the parameters p and C were fine-tuned using the reverse engineering approach. With the help of explicit dynamic simulations and all the experimental data, a multi-criteria cost function was defined and applied to obtain a smooth response function for the parameters p and C. Its optimum was determined by a real-valued genetic algorithm. The optimal values of the estimated parameters model the material response well, although a domain of optimum candidates spans two orders of magnitude for the parameter p and a few orders of magnitude for the parameter C.

The Quasi-Plastic Deformation Mechanisms and Inverse Hall-Petch Relationship in Nanocrystalline Boron Carbide under Compression

Abstract Grain boundary (GB) plays a significant role in the deformation behaviors of nanocrystalline ceramics. Here, we investigate the compression behaviors of nanocrystalline boron carbide (n-B4C) with varying grain sizes, using molecular dynamics simulations with a machine-learning force field. The results reveal quasi-plastic deformation mechanisms in n-B4C: GB sliding, intergranular amorphization, and intragranular amorphization. GB sliding arises from the presence of the soft GBs, leading to intergranular amorphization. Intragranular amorphization arises from the interaction between grains with unfavorable orientations and the softened amorphous GBs, finally causing structural failure. Furthermore, the n-B4C models with varying grain sizes from 4.07 nm to 10.86 nm display an inverse Hall-Petch relationship due to the GB sliding mechanism. A higher strain rate in n-B4C often leads to higher yield strength, following a 2/3 power relationship. These deformation mechanisms are critical for the design of ceramics with superior mechanical properties.

Image‐based inertial impact test for viscoelastic constitutive identification: A digital replica for error quantification

AbstractPolymers find widespread use in applications where they are subjected to impact loading. Therefore, understanding the time dependence of their mechanical response is critical to the design of structures subjected to these high strain rate environments. However, characterising these materials on microsecond time scales has proven challenging. Traditional experimental techniques rely on satisfying a number of limiting assumptions and typically do not provide direct measurements of the material parameters. Here, we propose a novel implementation of the image‐based inertial impact (IBII) test to extract viscoelastic constitutive parameters on these microsecond time scales using the stress gauge implementation of the virtual fields method. We validate the experiment using a digital replica approach in which the constitutive parameters are first extracted on a finite element model of an IBII test on a viscoelastic material. The finite element data are then used to synthetically deform computer‐generated grid images, which are then polluted with grey‐level noise to simulate the images that would be captured in a real‐life experiment. These images are processed identically to a physical experiment, and the identification is repeated using the full‐field displacements extracted from the computer‐generated images to determine the ideal processing parameters. Parameter identification was found to strongly depend on the processing parameters used to extract the kinematic fields from full‐field images, emphasising the need for computational validation before attempting a physical experiment to extract constitutive parameters. The IBII experimental method was found to be capable of simultaneously identifying the bulk modulus and the shear modulus along with their associated time constant.

Dynamic tensile behaviour of 7A04-T6 aluminium alloy at elevated temperatures

As typical light engineering metals, aluminium alloys are widely employed in modern manufacturing and construction sectors. Among them, 7A04-T6 high-strength aluminium alloy (AA7A04-T6), alloying with Zn, Mg and Cu and manufactured via the T6 temper process, is a good alternative to steel in construction and is now attractive to engineers and researchers. The structural members made from 7A04-T6 High-strength aluminium alloy are also vulnerable to a variety of accidental actions, such as impact and blast which expose the AA7A04-T6 material to both high strain rates and elevated temperature. To date, investigations into the mechanical properties of AA7A04-T6 material under the loading conditions with strain rates and temperatures coupled are still limited. Dynamic tensile tests were conducted under the rate-temperature coupling test conditions in this work, to study the influence of strain rate and temperature on the stress-strain response of AA7A04-T6 material. The ranges of the test strain rate and temperature were from 0.001 s−1 to 102 s−1 and from 20 ℃ to 200 ℃, respectively. Based on the classical Johnson-Cook model and Cowper-Symonds model, a modified model was proposed for AA7A04-T6 material and good agreement is achieved in the comparison between the predictions and the measured stress-strain curves, which could facilitate the relevant fine analysis and resilient design in the future.

Region specific anisotropy and rate dependence of Göttingen minipig brain tissue.

Traumatic brain injury is a major cause of morbidity in civilian as well as military populations. Computational simulations of injurious events are an important tool to understanding the biomechanics of brain injury and evaluating injury criteria and safety measures. However, these computational models are highly dependent on the material parameters used to represent the brain tissue. Reported material properties of tissue from the cerebrum and cerebellum remain poorly defined at high rates and with respect to anisotropy. In this work, brain tissue from the cerebrum and cerebellum of male Göttingen minipigs was tested in one of three directions relative to axon fibers in oscillatory simple shear over a large range of strain rates from 0.025 to 250s-1. Brain tissue showed significant direction dependence in both regions, each with a single preferred loading direction. The tissue also showed strong rate dependence over the full range of rates considered. Transversely isotropic hyper-viscoelastic constitutive models were fit to experimental data using dynamic inverse finite element models to account for wave propagation observed at high strain rates. The fit constitutive models predicted the response in all directions well at rates below 100s-1, after which they adequately predicted the initial two loading cycles, with the exception of the 250s-1 rate, where models performed poorly. These constitutive models can be readily implemented in finite element packages and are suitable for simulation of both conventional and blast injury in porcine, especially Göttingen minipig, models.

Crystal plasticity modeling and analysis for the transition from intergranular to transgranular failure in nickel-based alloy Inconel 740H at elevated temperature

The precipitation-strengthened Nickel-based alloy Inconel® 740H® (IN740H) exhibits increased ductility at higher applied strain rates during quasi-static tensile tests at an elevated temperature of 760 °C. The examination of fracture surfaces in this context reveals a noteworthy transition of underlying fracture mechanisms from transgranular to intergranular fracture as the applied strain rate decreases from 1×10−3/s to 0.83×10−4/s. To thoroughly understand the mechanical response of IN740H under these conditions, this study develops a crystal plasticity finite element (CPFE) model. This model incorporates various deformation mechanisms including dislocation slips, climb, and grain boundary sliding, which are relevant to the test conditions. The model is calibrated using data from both tensile tests at different strain rates and creep tests across a broad stress range at 760 °C, enabling the accurate determination of model parameters for each mechanism. Simulation results well captured the experimental observations of different failure modes. At higher strain rates, the model shows a dominance of dislocation slip leading to heterogeneous plastic deformation and formation of transgranular shear bands causing the failure, while at lower strain rates, an increased activity of grain boundary sliding causes grain boundaries crack leading to intergranular failure.

Influence of strain rate on the work hardening, strain induced martensite formation, strain partitioning, and variant selection in a medium-Mn steel

In this study, we investigated the effect of strain rate on the work hardening, strain-induced martensite transformation, strain partitioning, and crystallographic variant selection in a medium-Mn steel. Uniaxial compression tests were performed under quasi-static and dynamic loading conditions at the strain rates of 10−3, 1 and 103s−1. Besides, to determine the contribution of temperature rise due to adiabatic heating at a higher strain rate, compression tests were carried out at 409 K (estimated temperature rise) under quasi-static conditions. The work hardening rate was higher at high strain rates and it rapidly decreased at all strain rates up to a true plastic strain of ∼0.05. Beyond the true plastic strain of ∼0.05, the work hardening rate increased at a low strain rate up to a true plastic strain of ∼0.15 while at a high strain rate, it remained relatively constant and gradually decreased beyond a true plastic strain of ∼0.15. From the analysis of microstructures obtained from electron backscatter diffraction, it was observed that the strain-induced transformation of retained austenite to α′-martensite is significantly impeded at higher strain rates and in the sample tested at 409 K at low strain rates. The higher stability of retained austenite is attributed to the adiabatic heating which decreases the chemical driving force for retained austenite to martensite phase transformation and increases the stacking fault energy. Analysis of the misorientation axis and angle evolution revealed that while the Kurdjumov–Sachs relationship was followed under quasi-static conditions, it deviated at higher strain rates. Analysis of crystallographic variants related to strain-induced martensitic transformation at a true plastic strain of ∼0.15 revealed that the samples deformed at a lower strain rate did not show any noticeable variant selection. However, in samples deformed at a higher strain rate, a significant variant selection was observed. It is reasoned that the martensitic transformation nucleates initially on favorably oriented habit planes of retained austenite grains at all strain rates and other variants get activated with an increase in strain. As the transformation is impeded beyond a critical strain at a higher strain rate, the variants activated at lower strains remains predominant.

Compressive mechanical properties of styrene-butadiene rubber under medium-low strain rates: Experiments and modeling

Styrene-butadiene rubber (SBR) is widely employed as a cushioning material in engineering applications to resist impact loadings due to its excellent mechanical properties and energy absorption capacity. This paper aims to investigate the compressive mechanical properties and constitutive model of SBR under medium–low strain rates both experimentally and theoretically. Firstly, quasi-static and dynamic compression tests of SBR were carried out under the strain rate up to 220 s−1 using an electronic universal testing machine and a drop-weight machine, respectively. Subsequently, the effect of loading rate on mechanical properties, strain rate sensitivity and energy absorption capacity was examined. The results indicate that SBR exhibits visco-hyperelastic characteristics with reversible compression deformation and strain rate dependency, ie., the yield stress, flow stress and dynamic increase factor (DIF) increase approximately exponentially with increasing logarithmic strain rate. In addition, the SBR exhibits excellent energy absorption capacity during compression, especially under higher strain rates and larger strain levels. Finally, a visco-hyperelastic constitutive model was proposed by replacing the nonlinear spring with a hyperelastic element in Zhu-Wang-Tang (ZWT) viscoelastic constitutive model to describe the nonlinear mechanical behaviors in SBR, and an acceptable agreement between experimental results and model predictions were observed. The findings of this research can provide a valuable guide for designing and optimizing the impact resistance of SBR structures.

Constitutive model of viscoelastic dynamic damage for the material of gas obturator in modular-charge howitzer

In order to investigate the mechanical response behavior of the gas obturator of the breech mechanism, made of polychloroprene rubber (PCR), uniaxial compression experiments were carried out by using a universal testing machine and a split Hopkinson pressure bar (SHPB), obtaining stress-strain responses at different temperatures and strain rates. The results revealed that, in comparison to other polymers, the gas obturator material exhibited inconspicuous strain softening and hardening effects; meanwhile, the mechanical response was more affected by the strain rate than by temperature. Subsequently, a succinct viscoelastic damage constitutive model was developed based on the ZWT model, including ten undetermined parameters, formulated with incorporating three parallel components to capture the viscoelastic response at high strain rate and further enhanced by integrating a three-parameter Weibull function to describe the damage. Compared to the ZWT model, the modified model could effectively describe the mechanical response behavior of the gas obturator material at high strain rates. This research laid a theoretical foundation for further investigation into the influence of chamber sealing issues on artillery firing.

Effects of strain rate on dynamic deformation behavior and microstructure evolution of Fe-Mn-Cr-N austenitic stainless steel

In this work, the effects of strain rate on dynamic hot deformation behavior and microstructure evolution of Fe-Mn-Cr-N steel were studied under quasi-static and dynamic loading conditions using a Gleeble-3800 thermal-mechanical simulator and Split-Hopkinson pressure bar (SHPB) system. The stress-strain curves show that the yield and flow stresses are both significantly dependent on strain rate, also the strain rate sensitivity increases from 0.050 at a low strain rate (0.001–0.1 s−1) to 1.507 at a high strain rate (4500–5500 s−1). At a low strain rate (0.001–0.1 s−1), the microstructure evolution is dominated by dislocation slip and dynamic recovery (DRV). When strain rates are increased to 2500–3500 s−1, dislocation slip and mechanical twining together coordinate plastic deformation. When the strain rate was 4500–5500 s−1, the dynamic recrystallization (DRX) based on twinning formed in the deformation bands, and its fraction increased with the increasing strain rate due to adiabatic temperature rise (ΔT). The high micro-hardness value was obtained mainly because of the strain rate hardening (2500–3500 s−1), but the decrease at the strain rate of 4500–5500 s−1 is primarily attributed to recrystallization softening after deformation. The modified Johnson-Cook (J-C) model considering adiabatic temperature rise agrees with experimental results. It can be used to predict the plastic deformation behavior of Fe-Mn-Cr-N steel under high strain rate loading.

Dynamic tensile properties of a novel high strength and high toughness bolt steel: Constitutive models and microstructures

With the continuous increase of depth in underground engineering, rock bursts or rock explosions can cause instantaneous shock load and result in rock engineering disasters. To solve these problems, a novel high strength and high toughness (HSHT) bolt steel with constant resistance and large deformation is proposed. This study aims to investigate the dynamic constitutive models and microstructure of HSHT steel under extreme loading conditions. A series of dynamic tension tests were conducted using a Split Hopkinson Tensile Bar (SHTB) system with a high-speed camera. The results revealed that the HSHT steel exhibited a positive strain rate effect. As the strain rate increased from 1000 s−1 to 5000 s−1, the yield strength and ultimate strength of the HSHT steel increased gradually. However, no obvious changes in the uniform elongation. Specifically, the yield strength, tension strength, and uniform elongation of strain rate at 5000 s−1 were 1100 MPa, 1170 MPa, and 30%, respectively. According to the results of the SHTB tests, a modified Johnson-Cook model was proposed. Additionally, we investigated the microstructure of HSHT steel at a high strain rate through microscopic characterization techniques. A large number of fine and deep dimples were observed near the fracture of HSHT steel under dynamic loading. Moreover, the HSHT steel demonstrates a significant presence of nano-twins, which effectively impedes crack propagation both within the grain interior and along grain boundaries. The above findings reveal the relationship between mechanical behavior and microstructure in HSHT steel within dynamic loading conditions, providing valuable insights for the design of HSHT steel in underground engineering.

Investigation on dynamic deformation behavior of 7A75 aluminum alloy over wide strain rates and constitutive model establishment

The aluminum alloy components on automobile often experience high strain rate deformation during accidents. The dynamic deformation behavior and constitutive model are crucial for analysis of vehicle body collisions and failures. In this work, the 7A75 aluminum alloy plate was heat treated according to standard body manufacturing procedures. Quasi-static and dynamic tensile experiments were conducted on the aged 7A75 alloy in a wide strain rate range from 0.001 s−1 to 500 s−1. The dynamic deformation behavior of the alloy was revealed, and the constitutive models were established. It was found that the 7A75 alloy has strong strain rate sensitivity, and its mechanical properties can be significantly improved with the increase of strain rate. As the strain rate increases, the necking instability strain shifts towards higher values, which leads to a larger uniform deformation ability and fracture elongation. This behavior results in a better energy absorption capacity at high strain rates, thus providing a good collision protection property. The constitutive models, including Johnson-Cook (J-C) and Zerilli-Armstrong (Z-A) types, were established and compared. Note that the conventional J-C and Z-A models exhibit severe prediction distortion. Therefore, a modified J-C model incorporating strain rate compensation was introduced, which decrease the errors by 149% and achieves accurate predictions of both dynamic and static deformation behaviors over a wide range of strain rates.

Tensile and impact behavior of 3D-printed (FeCoNi)86Al7Ti7 high entropy alloy at ambient and cryogenic temperatures

High-entropy alloys (HEAs) demonstrate superior mechanical properties at room temperature, highlighting potential for engineering applications. With the increasing demand for advanced materials, especially in modern applications facing rigorous conditions, it becomes imperative to gain profound insights into the dynamic behavior of HEAs. In this study, the (FeCoNi)86Al7Ti7 HEA, renowned for exceptional printability and room-temperature mechanical properties, has been fabricated by selective laser melting (SLM), and its tensile and impact behaviors at ambient and cryogenic temperatures are systematically investigated. Experimental results reveal enhanced tensile properties as temperature decreases, achieving a high ultimate strength of 1313.6 MPa and impressive ductility of 24.8 % at 77 K. This improvement is attributed to the synergistic deformation mechanisms, including dislocation slip, stacking faults, Lomer and Lomer-Cottrell locks, which maintain a high strain-hardening rate and thus suppress strain localization. In contrast, impact properties deteriorate due to constrained dislocation mobility at high strain rates and low temperatures, with Charpy impact energy decreasing from 8.1 J at 293 K to 5.1 J at 77 K. Consequently, cracks readily initiate at cellular boundaries or defects, propagating in an intergranular manner and inducing localized deformation. This study provides valuable insights for the future applications of 3D-printed HEAs in extreme operational environments.

Thermomechanical constitutive behaviour of 3D printed biomimetic polymer material under high strain rates

With the continuous technical breakthroughs of flexible electronics, materials with outstanding application potential are constantly being designed and optimized. Biomimetic polymer materials are particularly appealing due to their versatility and ease of fabrication, but their mechanical reliability, particularly their thermomechanical constitutive behavior under extreme working loads, remains unclear. In this paper, the impact responses of a 3D printed biomimetic polymer material named “Tangoblack” are investigated under thermomechanical, focusing on the effect of strain rate. By adjusting the pressure of the gas gun in the split Hopkinson pressure bar, different strain rates are achieved, while the high temperature of the tested sample can be controlled using a heating furnace integrated into the experiment system. Materials for pulse shapers are carefully selected to ensure longer durations at nearly constant strain rates. The constitutive behaviour of the biomimetic polymer material is further investigated under a wide strain rate range from 958 s-1 to 2158 s-1 and three different temperatures (20 °C, 70 °C and 120 °C). The results demonstrate a significant dependence of the polymer material on both strain rate and temperature. A rapid increase in forming strain rate enhances the strain hardening process, while simultaneously revealing a substantial temperature softening effect. Then, an improved nonlinear thermoviscoelastic ZWT constitutive model is proposed utilizing the Vogel-Fulcher-Tammann equation and implemented as a user-defined material model in ABAQUS/Explicit. The proposed constitutive model is demonstrated to be distinctly advantageous, which suggests a novel pathway for describing the mechanical reliability of biomimetic polymer materials under extreme working conditions.

Dynamic mechanical properties and energy release characteristics of Mg-Na-Al alloy under impact load

To investigate the ignition behavior of Mg-Na-Al alloy under impact load and its mechanical properties under different strain rates, the universal testing machine and Separated Hopkinson Pressure Bar (SHPB) experimental system were used to conduct static and dynamic mechanical performance tests of Mg-Na-Al alloy, and the mechanical properties of Mg-Na-Al alloy under different strain rates were discussed. The light gas gun experimental setup was used to launch Mg-Na-Al alloy projectiles and impact rigid target plates to study the energy release behavior of Mg-Na-Al alloy under impact loads. Finally, based on the 12.7mm ballistic gun experimental platform, the penetration of 12.7mm armor-piercing projectiles equipped with Mg-Na-Al alloy wind caps into the homogeneous armor steel plates with a thickness of 15mm, and the ignition test of the oil box behind the steel plates were conducted. The results indicate that the yield strength of Mg-Na-Al alloy under static compression is 265MPa, while under high strain rates (from 2490s-1 to 5640s-1), the yield strength of Mg-Na-Al alloy is 406~423MPa, which is 53%~60% higher than that under quasi-static compression. When reaching a certain impact velocity, the Mg-Na-Al alloy projectile breaks and induces ignition behavior, releasing energy. The 12.7mm armor-piercing projectile equipped with an Mg-Na-Al alloy wind cap penetrated the homogeneous armor steel plate with a thickness of 15mm and ignited. The released energy and the kinetic energy of the fragments ignited the oil box behind the steel plate.

Strength-ductility materials by engineering a coherent interface at incoherent precipitates.

In the quest for excellent light-structural materials that can withstand mechanical extremes for advanced applications, design and control of microstructures beyond current material design strategies have become paramount. Herein, we design a coherent shell at incoherent precipitates in the 2195 aluminum alloy with multi-step metastable phase transitions. A high local strain rate via a neoteric deformation-driven metallurgy method facilitated the diffusion of Li. The original T1 (Al2CuLi) phases were transformed into coherent-shell (Li-rich) irregular-coated incoherent-core (Al2Cu) precipitates. The ultimate tensile strength and elongation reached 620 ± 18 MPa and 22.3 ± 2.2%, exhibiting excellent strength-ductility synergy. Grain boundaries, dislocation, solid solution atoms, and precipitates all contributed to the yield strength of the materials, among which precipitates occupied a dominant position, contributing approximately 56.07%. A new "incoherent-coherent interact" strain-hardening mechanism was also clarified, which was believed to be promoted in other heat-treatable alloy systems, especially with multi-step metastable phase transitions.

Nonlinear analysis model of the progressive damage of aluminum–wood sandwich structures under high-speed impact conditions

The impact responses of various protective structures composed of 2A12 aluminum alloy and wood laminates were studied experimentally. The experiments were conducted using different impact energies. By varying the sandwich material thickness and using two different bullet shapes, the effects of the sandwich material’s damage process and the core layer thickness on the protective performance were studied. The multilayer structure’s core layer failure condition was determined using the improved 3D Hashin criterion and a finite element model was established using Abaqus software. Tensile and three-point bending tests were conducted and the progressive damage model was verified statically. The model was then verified dynamically using the Hopkinson bar test. The mechanical properties of the materials under high dynamic strain rates were obtained through action loading testing of the specimens at different loading rates. The loading waveform was analyzed and a stress-strain relationship diagram was drawn at various strain rates. By verifying the experimental data, a numerical model that could capture the deformation and failure details during crushing was established, and the composite target plate impact failure mode and the trajectory change law were described. This study could lead to use of a new impact damage prediction method for laminates.

Effect of the loading-rate and stress state on the constitutive modelling and fracture of 2205 Duplex stainless steel

Shear cutting is a high-speed forming process where material separation is involved. The nature of the process leads to high strain rates and temperatures on the sheared zone of the material subjected to the operation. In this work, the mechanical behavior in terms of flow stress, plastic deformation and fracture of a 2205 Duplex stainless steel sheet is determined. Uniaxial tension, uniaxial compression, stack compression, plane strain tension and simple shear tests at different angles with respect to the rolling direction of the metal sheet are performed to determine the anisotropic behavior of the material. Strain rate and temperature dependence of the flow stress and the plastic behavior of the material is determined through notched tensile tests performed under various temperatures (20°C, 100°C, 300°C and 500°C) and strain rates (0.001 s−1, 10 s−1 and >100 s−1). Finally, fracture behavior under various stress states is determined through notched tensile, central hole, in-plane shear and plane strain tests. The temperature and strain rate dependence of the fracture behavior is determined through notched tensile, in-plane shear and plane strain tests performed under various temperatures (20°C, 100°C, 300°C and 500°C) and strain rates (0.001 s−1, 10 s−1 and >100 s−1). The anisotropic behavior and work hardening of the material are modelled by the Hill48 yield function and Swift-Hockett-Sherby hardening law, respectively. Among the two ductile fracture models tested, Hosford-Coulomb model showed the best agreement and is therefore used to account for the temperature and strain rate effects on the fracture behavior. By combining these three models, an accurate reproduction of the mechanical behavior of the 2205 Duplex stainless steel sheet is achieved.

Effect of equal channel angular pressing on magnesium alloys − A review

Magnesium (Mg) alloys own excellent properties that includes better castability, low density and great specific strength. Mg and its alloys are easily available and economical. Necessity of Mg and its alloys for manufacturing and engineering purposes has increased, predominantly in the area of aircraft and automobile applications. The known limitation of magnesium is its poor formability at room temperature, with inadequate slip systems due to hexagonal closed packed construction of magnesium. Formability of magnesium alloys will be enhanced at room temperature by grain structure refinement which improves ductility with grain refined structure. Severe plastic deformation (SPD) procedure induces extreme strain within the sample to produce ultrafine grained structure. Additionally, few shortcomings of magnesium is increased wear mass loss and corrosion rate obstructing the use of Mg and its alloys in several industrial appliances. Wear resistance and corrosion behaviour can be enhanced by SPD thereby increasing the requirement of magnesium alloys for engineering applications. Among SPD, equal channel angular pressing (ECAP) is an efficient approach to develop and vary the mechanical and microstructural properties as per the need. In ECAP approach, the workpiece undergoes shear deformation and large strains are induced in the workpiece with no variation in cross sectional aspect of the workpiece. Microstructure plays a very important role in achieving the required mechanical properties. ECAP process creates ultrafine-grained microstructure with different number of ECAP passes with varying temperatures inducing high strain rate.