Stress-strain curve measurements of aluminum alloy and carbon steel by unconstrained-type high-pressure torsion testing

Yogo, Yasuhiro; Sawamura, Masatoshi; Iwata, Noritoshi; Yukawa, Natsuo

doi:10.1016/j.matdes.2017.03.007

Cited by 9 publications

(8 citation statements)

References 14 publications

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“…It should be further noted that a large and thick ribbon was formed at the periphery of the sample after 1 HPT turn. This ribbon is also observed in other FEM investigations 25,44) and its length may be diminished by increasing the ratio of r/h.…”

Section: Hpt Facilities and Constraining Conditionssupporting

confidence: 81%

“…76) Further accomplishments in FEM modelling of HPT processing include models for the establishment of flow vortices in HPT-processed composites, 77) predictions of the evolution of texture in FCC metals, 42) simulations showing the influence of formation of anisotropic lamellar structure in pearlitic steel 78) and the development of an iterative model to measure stress-strain curves based on torque measurements during processing of disc-shaped samples using anvils having either constrained or unconstrained configurations. 43,44) It has been consistently shown throughout the numerous investigations summarised in this overview that the finite element method is recognized as an important mathematical tool capable of providing a better understanding concerning the flow behaviour and the microstructural evolution during HPT processing. Nevertheless, in view of the new developments in this research area, there remain numerous research questions which may be well addressed using this numerical method.…”

Section: Further Achievements and New Challenges In Hpt Modellingmentioning

confidence: 99%

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Finite Element Modelling of High-Pressure Torsion: An Overview

Pereira

Figueiredo

2019

Mater. Trans.

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Finite element modelling (FEM) has been extensively performed to study the flow process, the distribution of hydrostatic stress and the temperature rise in materials processed by high-pressure torsion (HPT). This overview provides a summary and a critical assessment of the most important findings obtained by means of these FEM simulations which permitted a better understanding about the microstructural evolution during processing by HPT. For convenience, FEM investigations focused on examining the nature of the HPT facility, the plastic flow, the hydrostatic pressure and the temperature evolution in HPT processing were separated into different topics. It is shown the distributions of strain, temperature and hydrostatic pressure along the disc diameter depend upon different factors such as the configuration of the HPT facility and the dimensions of the processed sample. [

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Section: Hpt Facilities and Constraining Conditionssupporting

confidence: 81%

Section: Further Achievements and New Challenges In Hpt Modellingmentioning

confidence: 99%

Finite Element Modelling of High-Pressure Torsion: An Overview

Pereira

Figueiredo

2019

Mater. Trans.

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“…A pressure F p of 4 GPa was imposed, and it was kept constant during the subsequent torsional loading. For steel, Yogo et al (2017) reported that application of pressure greater than 3 GPa is adequate to prevent slippage between the contacted disc–anvil surfaces. The pressure seems to be sufficient for AA2024 that is physically softer than steel, to hold the sample and provides a non-slip condition.…”

Section: Methodsmentioning

confidence: 99%

Hardening model of severe plastically deformed AA2024 by high-pressure torsion

Lamin

Ihsan

Mohamed

et al. 2020

IJSI

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PurposeThis paper aims to evaluate the validity of bilinear hardening model to represent the stress flow of high-pressure torsion (HPT)-strengthened lightweight material, AA2024.Design/methodology/approachFinite-element HPT simulation was performed by applying a simultaneous prescribed displacement on the axial and rotational axis that is equivalent to 4 GPa pressure and 30° torsion. The material behaviour incorporates plasticity attributes with a bilinear constitutive equation that consists of elastic and tangent modulus.FindingsAs a result, the von Mises stress generated from the simulation is in good agreement with the experiment, indicating that the assumptions of plasticity properties applied for the FEM simulation model are acceptable. The model verification confirms the anticipated plasticity parameters’ effect on the generated von Mises stress. The disc centre also evidenced an insignificant stress increment due to the limited shear straining.Research limitations/implicationsA reliable hardening model would assist in understanding the stress flow associated with mechanical properties enhancement.Practical implicationsThe bilinear hardening model exhibits a satisfactory stress estimation. It simplifies the ideal strain variable hardening procedures and lessens the total computation time that is valuable in solving severe plastic deformation problems.Originality/valueAn integration of well-defined input parameters, concerning the hardening behaviour and the plasticity properties, contributes to the establishment of a validated HPT simulation model, particularly for AA2024. This study also proved that perfectly plastic behaviour is inappropriate to represent hardening in the HPT-strengthened materials due to the remarkable stress deviation from the experimental data.

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“…However, a slippery contact surface is clearly not the case for HPT, where slippage between sample and anvils surfaces is intended to be prevented during the process. A non-slippery condition was mainly established in HPT to introduce a severe plastic deformation to the processed sample by the application of a sufficient compressive loading (Khoddam et al, 2016;Yogo et al, 2017) as well as the tool surface roughness (Cao et al, 2010;Lee et al, 2014). Therefore, higher friction coefficient approaching the required non-slip condition of µ ¼ 1.0 is more appropriate towards representing the actual HPT experiment.…”

Section: Effect Of Friction On Effective Plastic Strainmentioning

confidence: 99%

Finite element analysis of plasticity behaviour of aluminium alloys in high-pressure torsion compressive loading stage

Lamin

Ariffin

Mohamed

2019

IJSI

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Purpose The purpose of this paper is to examine the plasticity behaviour of aluminium alloys in high-pressure torsion (HPT) compressive loading stage. It is a part of the strengthen lightweight material development through severe plastic deformation. Design/methodology/approach A finite element simulation of HPT compression stage by displacement control incremental loading was proposed by taking into account an unconstraint HPT configuration. The quasi-static condition was utilised, by embedding strain hardening plasticity constitutive model and considering frictional effects, to assess the plasticity behaviour of aluminium alloys, particularly AA2024 and AA6082. Findings The present investigation clearly indicates that the deviation of material flow as a result of sticking condition of µ⩾0.5, was found to be negligible. An inhomogeneous material flow along the sample radial and thickness direction was evident, producing a stress concentration at the edge of the loaded surface, indicating the anticipated region of failure. The effective plastic strain in the compression stage was also found to be significant. Based on the effective strain response, plasticity behaviour of the compressed sample was predicted. Originality/value This paper demonstrates the plasticity behaviour of the analysed aluminium alloys. Since the mechanical properties produced by the deformed material are closely related to the exerted plastic deformation, understanding the phenomenon associated with the plastic strain development is essential. The outcome of this research will assist in seizing the opportunities of improving both material properties and the HPT procedures.

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Stress-strain curve measurements of aluminum alloy and carbon steel by unconstrained-type high-pressure torsion testing

Cited by 9 publications

References 14 publications

Finite Element Modelling of High-Pressure Torsion: An Overview

Finite Element Modelling of High-Pressure Torsion: An Overview

Hardening model of severe plastically deformed AA2024 by high-pressure torsion

Finite element analysis of plasticity behaviour of aluminium alloys in high-pressure torsion compressive loading stage

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