Hardening Exponents Research Articles

Influence of printing orientation on power-law hardening and ductile damage parameters for 3D-printed SS316L steel: experimental and FEA approach

In the present investigation, the selective laser melting (SLM) technique has been utilized for the 3-dimensional printing (tensile test specimens) of SS316L steel powder at 00 (horizontal) and 900 (vertical) angles. Further, an experimental and finite element analysis approach has been made to analyse the effect of printed orientation or direction on the Hollomon power law parameters (strain hardening exponent (n) and strength coefficient (K)) and ductile damage parameters (fracture strain (εf), stress triaxiality (η) and strain rate ( ε ̇ )). The influence of printing orientation on plastic deformation behavior has also been analysed. The results revealed that 00 angle 3D-printed specimens exhibited 11.05%, 21.97% and 9.50% more yield strength, tensile strength and elongation than 900 angle 3D-printed tensile test specimens. Further, the strain hardening exponent (n) and strength coefficient (K) (Hollomon power law hardening model parameters) for 00 angle 3D-printed specimens are 35.80% and 32.47% more than the 900 angle 3D-printed tensile test specimens respectively. The fracture strain for 00 angle 3D-printed specimens is 37.82% less than the 900 angle 3D-printed tensile test specimens. The percentage difference between FEA and experimental results is less than 5% which shows the good prediction capability of estimated Hollomon power law parameters and ductile damage model parameters with developed FEA model for 00 and 900 3D printed specimens.

The investigation on microstructure evolution and mechanical behavior of extruded Mg-1.5Al-xLa-Mn (x=0.5, 1, 2wt%) alloys

In this study, the microstructure evolution and mechanical behaviour of Mg-1.5Al-xwt%La-Mn (ALaM-x) (x = 0.5, 1, and 2) alloys with low-cost were investigated. Microstructure analysis of the cast alloys revealed that the Al11La3 was preferentially precipitated, followed by Al2La, and finally Mg12La, as the Al/La ratio decreased. Nonetheless, the main precipitated phase in the alloy was Al11La3 phase, and it gradually coarsened and the content increased, with the increase of La content. The fine rod-like Al11La3 was broken and refined after extrusion, while the coarse Al11La3 was not completely broken, and aggregated unevenly within Mg matrix. As a result, the grain size of the alloys gradually increased, and the strength gradually decreased. When adding 0.5 wt%La, compared with pure Mg, the ALaM-0.5 alloy exhibited finer grain microstructure with an average size of 1.83 μm and a grain refinement rate of 90%; the corresponding tensile yield strength (TYS) and ultimate tensile strength (UTS) are 262.5±3.0 MPa and 275.0±2.4 MPa, with an increase rate of 124.7% and 52.1%, respectively. The calculation and analysis of strengthening mechanism showed that the high strength of the alloy was mainly attributed to fine-grained strengthening with an accounting for up to 42%. Besides, the inverse relationship between the square root of the reciprocal of grain size (d−1/2) and strain hardening exponents (n) was found in this study, and the precipitates were found to delay the weakening trend of strain hardening capacity with decreasing grain size.

Further investigation of two-parameter J-A estimation for clamped SET specimens

Based on the J-A two-parameter characterization, this paper presents a systematic study of the crack-tip constraint for clamped single-edge notched tension (SET) specimens. Extensive finite element analyses (FEA) are conducted to obtain the A solutions for the modified boundary layer (MBL) model and the SET specimen. The material used in the analysis is the Ramberg-Osgood power-law material, with varying yield stress and strain hardening exponents. Based on previous studies, the T-stress-related A solutions for MBL problems under small-scale yielding conditions are obtained from FEA results, and the A solutions for the SET specimen are found to scale with normalized applied load under large-scale yielding conditions. By summing up these two solutions, the total A for the SET specimen can be estimated, covering the entire range from small-scale to large-scale yielding conditions. A key geometry factor is introduced as a function of material properties, crack depths and applied load. Some fitting equations are proposed in this estimation method, and a Python program is developed to quickly and accurately obtain the total A for the SET specimen. The results of the present study show good agreement for all the simulated cases. The proposed solutions of constraint parameter A can be used to establish the constraint-corrected J-R curve for SET specimens.

Microstructure characteristics and strain hardening behaviour of Ti17 linear friction welded joints

This study investigated the microstructure variations in Ti17 linear friction welded joints and evaluated the effect of strain rate and post weld heat treatment on the strain hardening behaviour. The welded zone of the as-welded joints consists of equiaxed β grains, while the prior-β grains in the thermal mechanical affected zone are severely deformed. After heat treatment, fine needle-like α S precipitates dispersed in the β matrix strengthen the tensile properties. The fracture mechanism transforms from brittle to ductile. The strain hardening capacity and exponent are negatively correlated with strain rate. At higher strain rates, the strain rate sensitivity increases during the initial stage of deformation.

Constitutive relations of nanoscale hydration products present in engineered cementitious composites from machine learning assisted experimental nanoindentation

In this work, a method to evaluate the stress-strain properties (at nano-scale) of constitutive phases present in the hydration cement matrix is presented. Using an experimental grid nanoindentation using Berkovich indenter, the constituent phases i.e., Low Density Calcium Silicate Hydrate (LD CSH), High Density Calcium Silicate Hydrate (HD CSH) and clinkers are indented upon during different points of Ordinary Portland Cement (OPC) paste hydration. Further, this study is conducted on four other cement pastes: OPC +20% fly ash, OPC +40% fly ash, OPC +0.5% nanosilica and OPC +1% nanosilica. Using experimental grid nanoindentation technique results in a large dataset depending upon the size of the gird. Three different machine learning algorithms including K-means, Gaussian mixture model (GMM) clustering and, support vector machine (SVM) have been implemented. The developed stress-strain evaluation method has allowed to ascertain the constitutive relations as yield stresses of 354 MPa for LD CSH, 393 MPa for HD CSH and 4340 MPa for clinkers, yield strains of 1.8 × 10−2 for LD CSH, 1.1 × 10−2 for HD CSH and 3.7 × 10−2 for clinkers; ultimate stresses of 371 MPa for LD CSH, 424 MPa for HD CSH and 6085 MPa for clinkers, ultimate strains of 2 × 10−2 for LD CSH, 1.4 × 10−2 for HD CSH and 4.4 × 10−2 for clinkers; and strain hardening exponents of 0.85 for LD CSH, 0.72 for HD CSH and 2.1 for clinkers. Elastic modulus, hardness and the stress-strain values obtained from the load vs. displacement curves are used for the clustering analysis and compared with deconvolution results. These properties have been used to test the feasibility of application of machine learning algorithms to classify the grid nanoindentation data. It was found that the machine learning algorithms were indeed capable of clustering the data obtained from experimental grid nanoindentation. This study presents a novel method to evaluate stress-strain properties of the constituent phases present in the cement microstructure and application of machine learning in the field of material characterisation using nanoindentation technique.

A novel flat indentation test method for obtaining stress–strain relationships of metallic materials based on energy density equivalence

For power-law hardening metallic materials under flat cylindrical indentation loading conditions, a theoretical model was derived to describe the relationships among the stress and strain of the equivalent material representative volume element, load, displacement, and diameter of the indenter based on energy density equivalence. Subsequently, a novel flat indentation test method was developed such that the stress vs. strain data points of a material with a known elastic modulus could be directly calculated by utilizing the collected load vs. displacement data points. Numerical verifications were performed on 64 elastoplastic materials with various combinations of elastic moduli, yield strengths, and strain hardening exponents. In addition, flat indentation tests were carried out on 12 metallic materials. The results showed that the stress–strain curves obtained by the proposed method were consistent with those pre-input in finite element analysis and those obtained from uniaxial tensile tests. Furthermore, the proof strength and tensile strength of the experimental materials were obtained according to the predicted Hollomon law parameters, and the relative errors between the predicted and standard test results were mostly within 3%.

Evaluation of the plastic deformation behavior of modified 100Cr6 steels with increased fractions of retained austenite using cyclic indentation tests

Abstract In highly loaded components, such as roller bearings, early failures may occur due to microstructural defects. Thus, a higher defect tolerance of the material can improve the fatigue lifetime. To produce steels with high defect tolerance, innovative alloying concepts, and a sound knowledge of the influence of heat treatment parameters on the resultant mechanical properties is indispensable. Consequently, two bearing steels based on 100Cr6 with different silicon contents were investigated to achieve relatively high retained austenite (RA) fractions, which are assumed to increase the defect tolerance at cyclic loading. To understand the relation between bainitic heat treatment and mechanical characteristics, the resultant RA fractions, Vickers hardness, microhardness, and cyclic hardening exponent CHT eII, which correlates to defect tolerance of metallic materials, were determined for differently heat-treated conditions. Based on the statistical design of experiments and measurements obtained with X-ray diffraction and cyclic indentation testing, regression calculations were conducted. Pertaining to the results of the regression analyses, the heat treatment parameterizations of these steels were specifically determined for certain desired property combinations within the boundaries investigated. Therefore, the temperatures used in the austenitizing and bainitizing procedures have shown the highest influence on the mechanical characteristics and the RA fraction of both steels.

Two-parameter elastic-plastic fracture criterion and corrected fracture toughness

The basic aspects of the J-A concept of elastic-plastic two-parameter fracture mechanics, based on a three-term asymptotic description of the stress field at the crack tip are presented. It is noted that the field of elastic-plastic stresses at the crack tip is controlled by two parameters of fracture mechanics, namely, J-integral and parameter A. Parameter A is a measure of the deviation of the stress field from the HRR-stress field and can be considered a parameter of elastic-plastic constraint at the crack tip both under conditions of small- and large-scale yielding. The results of studying the influence of the exponent of the strain hardening of the material, crack aspect ratio and the thickness of standard specimens with a crack on the elastic-plastic stress intensity factor and parameter A are presented. A two-parameter elastic-plastic J-A fracture criterion based on the relationship between J-integral and strain(stress) on the surface of the crack-notch and the principle of linear summation of damage is formulated. To reflect the crack-tip constraint, the parameter A is introduced into the criterion equation as a function of applied failure stresses. The elastic-plastic fracture toughness as a function of the crack-tip constraint in the fracture criterion is interpreted as the corrected elastic-plastic fracture toughness of a specimen with the corresponding constraint parameters A. The results of studying the normalized corrected fracture toughness as a function of failure stresses, crack aspect ratio and strain hardening exponent of the material are presented.

Low-Temperature Deformation Mechanism and Strain-Hardening Behaviour of Laser Welded Dual-Phase Steels

This paper analysed the change in microstructure after laser welding DP800 and DP1000, the effect of the laser welds on low temperatures deformation, and strain hardening behaviour when loaded at temperatures between −40 °C and 20 °C using quasi-static strain rates (1.7 × 10−2 s−1). The results showed that the fusion zone (FZ) was fully martensitic due to the rapid cooling during welding. Owing to the severity of the heat-affected zone, the joint efficiencies of DP800-DP800 and DP1000-DP1000 welds were 99.0% and 88.7%, respectively. The UTS, YS, and work hardening exponents of the welded joints increased slightly, while the strain hardening capacity of the base metals was much higher than those of the welded joints with decreasing temperatures. The evaluated work hardening exponents of the welded joints were determined using the Hollomon equation, Afrin equation, and Crussard-Jaoul analysis are in the range of 0.2–0.47, 0.24–0.59, and 0.45–0.71, respectively. The welded joints and the base metals demonstrated only stage III strain hardening, with DP800 joints exhibited excellent uniform and total elongation ranging between 8.0–8.7% and 10.4–14.2%, respectively. Fractures were located in the base metal of welded DP800 and SCHAZ of DP1000 welds, respectfully. The fracture surfaces demonstrated characteristic dimple fractures. The uniqueness of this study is found in its design, as there is currently no known literature on the low-temperature deformation mechanism and strain-hardening behaviour of similar DP800 and DP1000 welds.

Data-Driven Derivation of Sheet Metal Properties Gained from Punching Forces Using an Artificial Neural Network

The ongoing digitization of production processes provides new possibilities and potentials for process monitoring of forming and stamping processes. The component quality achievable by these processes is strongly dependent on the properties of the sheet metal material, so that a permanent digital recording of material data offers high potential for monitoring each component produced. In this context, presented paper deals with a novel AI-based method for the direct determination of ma-terial parameters from measured punching force curves. Using software systems Python and Tensor-Flow, an artificial neural network was first set up to determine mechanical material parameters (out-put data) from punching force curves (input data). As data basis for the adopted neural network, force curves were measured during punching of various sheet metal materials using a punching tool equipped with a direct force measurement device. Punching force curves were experimentally deter-mined for the sheet metal materials DP1200, DP1000, DP800, DP600, HX380LA, DC03 and DX54. Additionally, tensile tests were performed for these sheet metal materials to determine ultimate tensile strengths (Rm), yield strengths (Rp0.2, Re), uniform strains (Ag), elongations at break (At) and strain hardening exponents (n). The presented paper reveals that neural networks can accurately quantify the relationship between characteristic parameters of punching force curves and the mentioned me-chanical material properties.

Flexural buckling of extruded high-strength aluminium alloy SHS columns

The structural performance and design of extruded high-strength aluminium alloy square hollow section (SHS) columns were presented in this paper. A total of 12 extruded 7A04-T6 aluminium alloy SHS column specimens were tested under axial compression, together with tensile coupon tests and initial global geometric imperfection measurements. The flexural buckling failure mode and axial load versus end shortening and mid-height lateral deflection curves were reported. Based on validated finite element (FE) models, 480 numerical results were generated by means of parametric studies over a broad range of cross-section dimensions, member lengths, proof strengths and strain hardening exponents of the aluminium alloy material. The applicability of current design rules used for normal-strength aluminium alloy columns in European, Chinese and American standards to extruded 7A04-T6 high-strength aluminium alloy SHS columns was evaluated through comparisons with the test and FE results. The analysis results showed that the three standards consistently yielded conservative axial compression resistance predictions by about 9% for extruded 7A04-T6 high-strength aluminium alloy SHS columns. New flexural buckling curves with linear and nonlinear imperfection terms for the Chinese code, as well as modifications to the American specification, were separately proposed, resulting in improved accuracy with significantly reduced scatter. Additionally, the continuous strength method (CSM) was further extended for the flexural buckling design of extruded 7A04-T6 high-strength aluminium alloy SHS columns, and was shown to provide accurate and consistent resistance predictions. Reliability analyses of the codified and the proposed design methods were performed, confirming that the design proposals meet the target reliability indices except the Eurocode approach.

The Application of a Hybrid Method for the Identification of Elastic-Plastic Material Parameters.

The indentation test is a popular method for the investigation of the mechanical properties of materials. The technique, which combines traditional indentation tests with mapping the shape of the imprint, provides more data describing the material parameters. In this paper, such methodology is employed for estimating the selected material parameters described by Ramberg–Osgood’s law, i.e., Young’s modulus, the yield point, and the material hardening exponent. Two combined identification methods were used: the P-A procedure, in which the material parameters are identified on the basis of the coordinates of the indentation curves, and the P-C procedure, which uses the coordinates describing the imprint profile. The inverse problem was solved by neural networks. The results of numerical indentation tests—pairs of coordinates describing the indentation curves and imprint profiles—were used as input data for the networks. In order to reduce the size of the input vector, a simple and effective method of approximating the branches of the curves was proposed. In the Results Section, we show the performance of the approximation as a data reduction mechanism on a synthetic dataset. The sparse model generated by the presented approach is also shown to efficiently reconstruct the data while minimizing error in the prediction of the mentioned material parameters. Our approach appeared to consistently provide better performance on the testing datasets with considerably easier computation than the principal component analysis compression results available in the literature.

Analysis of spring back behaviour during bending of AISI 1045 sheet metal

Springback during forming process shows the elastic recovery of the sheet metal which indicates the physical change that happens during the deformation of the metal. Springback is being affected by various factors like sheet thickness, tooling geometry, lubricating conditions, material properties and processing parameters. The learning of spring back characteristics of AISI1045 sheets during the air bending process was performed in this paper. ExperimentalThe actual influence of control parameters namely Orientations (strain hardening exponent) (θ), breadth of the sheet (Ws), Punch travel (dp), Holding time (hd) and Punch Velocity (v) on spring back behavior were established during the experimental investigations conducted on the meshed mild steel. The conduction of experiments showed the increase of spring back when the process parameters such as punch travel, velocity, and width of the sheets were increased. Trials also showed the reduction due to the increase of holding time. Finally it was resolved that punch travel was identified as the dominant factor among the others through a statistical tool called Analysis of Variance (ANOVA).

Study of strain rate sensitivity exponent and strain hardening exponent of typical titanium alloys

In this study, the flow stress-strain curves of three typical titanium alloys, cast TA15 titanium alloy (near α-type), cast Ti40 titanium alloy (full β-type) and cast TC21 titanium alloy (α + β-type), were obtained based on hot compression tests, based on which the deformation activation energy, softening fraction, strain rate sensitivity exponents and strain hardening exponents of the three typical titanium alloys were calculated under different process parameters and analyzed The variation law of each parameter was analyzed. The effect of nascent grain size on the strain rate sensitivity exponent and strain hardening exponent was analyzed by counting the dynamic recrystallization grain size of the alloy. The results show that the deformation activation energy of Ti40 titanium alloy is much higher than that of TA15 and TC21 titanium alloys during thermal deformation, mainly because the alloying element content of Ti40 titanium alloy is much higher than that of the other two. The maximum value of strain rate sensitivity exponents m is obtained at the minimum strain rate for all three titanium alloys, and the deformation temperature also has a great influence on the value of m. Combined with the microstructure of the material under different deformation conditions, it is found that the effect of strain and strain rate on the strain hardening exponents n is very significant. Moreover, grain refinement during deformation can effectively increase the strain rate sensitivity exponent and reduce the strain hardening exponent.

Effect of Plastic Anisotropy on Ironing Formability of 3104 Aluminum Alloy Hard Sheets

3104 aluminum alloy hard sheets are widely used for aluminum beverage can body stock (CBS) mainly because of their high ironing formability. The CBS has large anisotropy of r-value (Lankford value) and n-value (work hardening exponent), however, the effect of such anisotropy on the ironing formability remains unclear. In this study, cup and DI forming behavior was investigated using cold-rolled 3104 aluminum alloy hard sheets with different anisotropy of r and n-values. Magnitude of the anisotropy changes during drawing and ironing. Ironing fracture tests reveal that fracture occurs at angles between 10 and 20° in the can circumferential direction. From the strain distribution measurement of the can wall, it is found that the axial strain of the can wall at the fracture angle is larger. A theoretical analysis method of ironing stress introducing r and n-value anisotropy is devised based on the Hill’s anisotropic plasticity theory (quadratic yield function). The devised analysis reveals that as the anisotropy of r-value in the can wall becomes smaller, (1) the fracture is less likely occur, (2) the margin of stress which calculated from the ratio of the can axial tensile stress to fracture stress is larger.

Virtual design of formability for Zircaloy-4 sheet through texture control

Zircaloy-4 (Zr-4) sheet is commonly used in fuel assembly structural parts as spacer grids which are subjected to high temperature and stresses, corrosive and radiation environment. The knowledge regarding the properties and the formability with respect to initial texture of Zr-4 sheet is not enough. In this paper, finite element method was used to simulate the forming process of Zr-4 sheet, and effect of different initial hardening exponent (n value) on the formability of sheet is studied. The results show formability of sheet reveals better with larger n value. However, the hardening exponent (n value) is closely related to the features of initial texture of sheet. Thus, the well-established polycrystal plasticity method, visco plastic self-consistent (VPSC) model, was used to predict the effect of different initial textures on the hardening exponent of Zr-4 sheet, and plastic deformation mechanism of different initial textures in stamping process was analyzed. The results show that a larger the hardening exponent is obtained under a smaller normal Kearn factor (Fn) of the initial texture, and the activation of prismatic slip decreases with increasing the Fn.

Effects of Osteoporosis on Bone Morphometry and Material Properties of Individual Human Trabeculae in the Femoral Head.

ABSTRACTOsteoporosis is the most common bone disease and is conventionally classified as a decrease of total bone mass. Current diagnosis of osteoporosis is based on clinical risk factors and dual energy X‐ray absorptiometry (DEXA) scans, but changes in bone quantity (bone mass) and quality (trabecular structure, material properties, and tissue composition) are not distinguished. Yet, osteoporosis is known to cause a deterioration of the trabecular network, which might be related to changes at the tissue scale—the material properties. The goal of the current study was to use a previously established test method to perform a thorough characterization of the material properties of individual human trabeculae from femoral heads in cyclic tensile tests in a close to physiologic, wet environment. A previously developed rheological model was used to extract elastic, viscous, and plastic aspects of material behavior. Bone morphometry and tissue mineralization were determined with a density calibrated micro‐computed tomography (μCT) set‐up. Osteoporotic trabeculae neither showed a significantly changed material or mechanical behavior nor changes in tissue mineralization, compared with age‐matched healthy controls. However, donors with osteopenia indicated significantly reduced apparent yield strain and elastic work with respect to osteoporosis, suggesting possible initial differences at disease onset. Bone morphometry indicated a lower bone volume to total volume for osteoporotic donors, caused by a smaller trabecular number and a larger trabecular separation. A correlation of age with tissue properties and bone morphometry revealed a similar behavior as in osteoporotic bone. In the range studied, age does affect morphometry but not material properties, except for moderately increased tissue strength in healthy donors and moderately increased hardening exponent in osteoporotic donors. Taken together, the distinct changes of trabecular bone quality in the femoral head caused by osteoporosis and aging could not be linked to suspected relevant changes in material properties or tissue mineralization. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Microstructure and Mechanical Properties of the AA7075T7352 Aluminum Alloy

Microstructure evolution and their effects on mechanical behaviors of the AA7075T7352 aluminum alloy are reported. Phase analysis was done by X-ray diffraction and transmission electron microscope. The presence of the GP-Zones, ɳ', and ɳ, along with Al2Cu, Al2CuMg, and Al3Zr, was noticed. Mechanical characterizations were done with the help of a tensile test and Vickers microhardness. Flow behaviors were studied to evaluate the impact of second-phase particles in the properties. Strain hardening exponents along with UTS/YS ratio have been calculated. Flow curve fitting follows Ludwigson relationship with two distinct slopes. Dislocation loops and forest dislocation were noticed in the low strain range, while dense dislocation walls in the high strain range. Variation in flow parameters is due to the random spread of precipitate particles in the matrix. The material fails by mixed mode of ductile and brittle fractures.

Simplified method to identify full von Mises stress-strain curve of structural metals

The relationship between von Mises equivalent stress σ¯ and equivalent plastic strain ε¯ (PEEQ), termed as von Mises stress-strain, plays an important role in numerical simulations for ductile fracture of structural metallic materials with large plastic strain. The standard uniaxial tensile test on cylindrical specimens is the most straightforward method to derive the (σ¯−ε¯) data. However, the distribution of the stress and strain along the necking section of the tensile specimen is no longer uniform in the post-necking process, which induces difficulty in acquiring the (σ¯−ε¯) data. The existing correction methods to identify von Mises stress-strain in the post-necking regime need instantaneous geometry of the notched region and ignore influence of the initial geometry of the specimen, which induces these methods are inconvenient for application and inapplicable for circumferentially notched tensile specimens to determine (σ¯−ε¯) of each individual material zone in a hybrid coupon (e.g. weldment). In the present study, influences of initial geometry of the specimen and plastic hardening property of material on necking process are investigated firstly. It is found that the shrinking behavior of the minimum cross-section of the specimen is determined by the geometric parameter of specimen and plastic hardening exponent of materials. Based on an extensive parametric study a modified power law function to characterize the von Mises stress-strain curve from tensile tests on circumferentially notched specimens without measuring instantaneous geometry of cross-section is proposed.

Heterogeneous microstructure and deformation behavior of an automotive grade aluminum alloy

Aluminum alloy is today considered as a prime selection for manufacturing lightweight structural components in the automotive industry to increase fuel efficiency and reduce harmful emissions. The aim of this study was to identify the effect of microstructure and strain rate on the tensile deformation behavior of a high-pressure die-cast Silafont®-36 alloy, with special attention to strain hardening behavior and deformation mechanisms. The alloy consisted of randomly oriented primary α-Al phase and Al–Si eutectic structure in a form of heterogeneous microstructures, with Sr-modified Si particles exhibiting a coral-like fibrous network. The local misorientations in most primary α-Al grains was below 1°, suggesting strain-free grains along with some extent of near-boundary residual strains due to the thermal mismatch between aluminum and silicon. A superior strength-ductility combination was achieved, along with enhanced Young’s modulus and quality index owing to the unique heterogeneous microstructures. The cast alloy exhibited a smooth deformation characteristic with good coordination deformation and strong strain hardening capacity. Strain hardening exponents evaluated via the equations proposed by Ludwik, Hollomon, Swift, and Afrin et al., respectively, showed basically the absence of strain-rate effect from 1 × 10−5 to 1 × 10−2 s−1. During the tensile deformation, crack initiated from the sample surface and propagated through the alternate microconstituents of softer primary α-Al phase and harder eutectic structure.