A new experimental approach for modelling the constitutive behaviour of sheet metals at elevated temperature through interrupted bulge tests

Guglielmi, Pasquale; Sorgente, Donato; Lombardi, Andrea; Palumbo, G.

doi:10.1016/j.ijmecsci.2020.105839

Cited by 7 publications

(3 citation statements)

References 46 publications

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“…To evaluate the combined effect of these factors on the stress-strain curves obtained at different strain rates, the material model provided in [30] for the approximation of flow behavior of AA5083 alloy at 470 • C was used. The model is described by Equation (6). The results of these simulations are presented in Figure 11.…”

Section: The Effect Of Strain Ratementioning

confidence: 99%

“…Thus, the experimental methods of mechanical testing, providing information about the flow behavior of superplastic materials, deserve extensive and thorough analysis. Aiming to reproduce the stress conditions realized in real forming processes, sustained efforts have been made to develop technological experiments and characterization techniques based on bulge [3][4][5][6], cone [7], and tube [8] forming tests. Nevertheless, tensile testing at constant strain rate remains the most widely used experimental way providing information about the deformation behavior of superplastic materials.…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Material Properties on the Accuracy of Superplastic Tensile Test

Aksenov

Mikolaenko

2020

Metals

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Tensile testing is widely used for the mechanical characterization of materials subjected to superplastic deformation. At the same time, it is known that the obtained flow data are affected by specimen geometry. Thus, they characterize the specimen rather than the material. This work provides the numerical analysis aimed to study how the material flow behavior affects the results of tensile tests. The simulations were performed by the finite element method in Abaqus software, utilizing user-defined procedures for calculation of forces acting on the crossheads. The accuracy of tensile testing is evaluated by the difference between the input material flow behavior specified in the simulations and the output one, obtained by the standard ASTM E2448 procedure based on the predicted forces. The results revealed that the accuracy of the superplastic tensile test is affected by the material properties. Even if the material flow behavior follows the Backofen power law, which is invariant for the effective strain, the output stress–strain curves demonstrate significant strain hardening and softening effects. The relation between the basic superplastic characteristics and the tensile test errors is described and analyzed.

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Section: The Effect Of Strain Ratementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Effect of Material Properties on the Accuracy of Superplastic Tensile Test

Aksenov

Mikolaenko

2020

Metals

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“…Owing to its exceptional combination of high specific strength, low density, and excellent corrosion resistance, among other advantages, the Ti-6Al-4V alloy finds extensive applications in aviation, medical, automotive, and various other industries [1][2][3]. Over the 80 years since its discovery, superplasticity refers to the performance of a material that can achieve large elongation without fracture in a specific temperature and strain rate range [4,5]. Superplastic forming (SPF) enables the processing of complex structures [6,7].…”

Section: Introductionmentioning

confidence: 99%

The Constitutive Equation-Based Recrystallization Mechanism of Ti-6Al-4V Alloy during Superplastic Forming

Chang,

Yang

2024

Coatings

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The present paper is concerned with the dynamic recrystallization of the Ti-6Al-4V alloy. Electron Backscatter Diffraction (EBSD) observations are performed after high-temperatures tensile tests, with the temperature ranging from 700 to ~950 °C, and the strain rates varying between 10−4 and 10−2/s. Based on the analysis of flow behavior, the dominant mechanism is identified, and a mechanism map is proposed. In particular, the conditions of 890 °C and strain rates ranging from 10−3 to ~10−2/s serve as the delineating boundary of dynamic recovery (DRV) and dynamic recrystallization (DRX). For superplastic deformation, the dominant softening mechanism is DRV. Consequently, the occurrence of continuous dynamic recrystallization (CDRX) can naturally be ascribed to the process of grain refinement. Then, a multi-scales physical-based constitutive model of CDRX is developed, demonstrating a good agreement is obtained between the experimental and calculated grain sizes, so the above model could be used to describe the grain growth for superplastic deformation. In conclusion, DRV and DRX in the superplastic forming of Ti-6Al-4V are studied in this study, the condition boundaries of their occurrence are distinguished, and a constitutive equation-based CDRX recrystallization mechanism is given, which might be employed in the fracture mechanism research.

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