Finite element analysis for the geometry effect on strain inhomogeneity during high-pressure torsion

Lee, Dong Jun; Kim, Hyoung Seop

doi:10.1007/s10853-014-8283-3

Cited by 23 publications

(14 citation statements)

References 29 publications

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“…Among various types of SPD methods such as high pressure torsion (HPT) [2][3][4] or accumulative roll bonding (ARB) [5,6], because of several reasons, the equal channel angular extrusion (ECAE) [7,8] has been nearly the most preferred one. However, ongoing attempts have been made by different investigators in order to improve and increase the efficiency of various SPD methods.…”

Section: Introductionmentioning

confidence: 99%

Expansion equal channel angular extrusion, as a novel severe plastic deformation technique

Sepahi-Boroujeni

Fereshteh-Saniee

2015

J Mater Sci

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A novel severe plastic deformation (SPD) process, namely expansion equal channel angular extrusion (Exp-ECAE) is proposed in this paper. With this regard, a spherical cavity is provided at the junction of the ECAE channels. The numerical simulations of the Exp-ECAE process resulted in finding suitable tool geometry for this operation. Using this optimum shape, several practical Exp-ECAE experiments were conducted with AA6063 aluminum at different process conditions. Because of the expansion cavity, a pseudo back-pressure mechanism was provided for the tests. The experimental findings showed that after the 1st pass of the Exp-ECAE process, the yield stress and hardness of the material were increased about 300 and 50 %, respectively. These improvements were much more than those achieved via other SPD techniques such as ECAE and twist extrusion for the same alloy. The homogeneity of hardness distribution along the cross section of the Exp-ECAE product was also acceptable. Further passes of the process just resulted in better ductility for the component such that after the 3rd pass, almost 97 % of ductility of the annealed billet was recovered. However, a slight decrease in the strength of the product was observed after the 2nd and 3rd passes.

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Section: Introductionmentioning

confidence: 99%

Expansion equal channel angular extrusion, as a novel severe plastic deformation technique

Sepahi-Boroujeni

Fereshteh-Saniee

2015

J Mater Sci

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“…The themes and variables investigated in this paper and the corresponding simulation parameters are listed in Table 1. In order to avoid slipping between the sample and the dies, the friction was set to satisfy the sticking condition in simulation [9,13]. D 1 and θ are the depth of the concave on the cylinder and the half cone angle of the die in t-HPS pressurized by wedge effect, and D 2 is the wall thickness of the pressurizing ring in t-HPS pressurized on both ends of the tube, these parameters are variables, as shown in Figure 1b,c.…”

Section: Methodsmentioning

confidence: 99%

“…Equation (2) shows that there is a linear strain gradient along the radial direction for HPT, while along the axial direction, the strain distribution is homogeneous. However, several researchers [8][9][10][11][12] reported that along the axis direction inhomogeneity of strain, hardness and microstructure also appeared, and the "dead metal zone" (DMZ) [13] at the corner of the sample was found for HPT. The strain inhomogeneity during the HPT is closely related to the die and sample geometries [9,14].…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Strain Distribution in Tube High-Pressure Shearing

Meng

Liu

et al. 2019

Metals

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The Finite-element method (FEM) and experiments were used to investigate the geometric factors and material parameter on the strain distribution during tube high-pressure shearing (t-HPS). The results show that t-HPS could be realized successfully either by pressurizing on both ends of the tube, or by pressurizing using the wedge effect; and in both cases, the “dead metal zone” could be found at both ends of the tube. The grain size distribution from the experiment confirmed this strain distribution feature. In the case of t-HPS pressurized using the wedge effect, the half cone angle has little effect on the strain distribution. Decreasing the strain-hardening exponent leads to increased deformation inhomogeneity in both the ideal t-HPS described by theoretical equations and the close to practical t-HPS described by FEM. This feature of t-HPS stands out from other SPD processes like HPT, and makes practical t-HPS behavior more predictable using the analytical formation than any other SPD processes, and places it an advantageous position in understanding the basics of deformation physics through the coupling between practical experiments and theoretical approaches.

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“…Finite element analyses were also performed to investigate the flow process during the compression-torsion stage in quasi-constrained HPT. These FEM simulations used either bi-dimensional 2224,49) or three-dimensional 13,14,37,39,40) models to represent the HPT facilities. The first FEM study of quasi-constrained HPT was conducted using a 3D model in Fig.…”

Section: Flow Process In High-pressure Torsionmentioning

confidence: 99%

“…9. 39) In these simulations, the shallow depressions of the anvils have a depth of 0.25 mm and the inclinations of the lateral walls vary between 0 up to 75°. Fig.…”

Section: Flow Process In High-pressure Torsionmentioning

confidence: 99%

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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Finite element analysis for the geometry effect on strain inhomogeneity during high-pressure torsion

Cited by 23 publications

References 29 publications

Expansion equal channel angular extrusion, as a novel severe plastic deformation technique

Expansion equal channel angular extrusion, as a novel severe plastic deformation technique

Investigation on the Strain Distribution in Tube High-Pressure Shearing

Finite Element Modelling of High-Pressure Torsion: An Overview

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