Feasibility of attaining uniform grain structure and enhanced ductility in aluminum alloy by employing a beveled punch in equal-channel angular pressing

Nejadseyfi, Omid; Shokuhfar, Ali; Sadeghi, Seyedali

doi:10.1016/j.msea.2015.08.050

Cited by 8 publications

(9 citation statements)

References 30 publications

(45 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is clear that the strain is inhomogeneously distributed throughout the sample. This is in line with the previous findings of different researchers investigating the deformation inhomogeneity during ECAP . However, in the case of the die with the choked exit channel, the strain is more inhomogeneousely distributed.…”

Section: Resultssupporting

confidence: 92%

Die Design Modification to Improve Workability during Equal Channel Angular Pressing

et al. 2016

View full text Add to dashboard Cite

The effect of choked and relieved configurations of die exit channel on the workability of AA6063 alloy during equal channel angular pressing (ECAP) is investigated. Finite element simulation is used to predict variation in maximum principal stress (s 1 ) to be consequently correlated to the occurrence of surface cracking. Critical regions for fracture are found at the top surface of the sample at which tensile s 1 exists. Tensile stresses are involved when dies with parallel or relieved exit channels are used while the stresses are compressive in case of die with choked exit channel. Choke angle of 0.2 is found as the optimum value guaranteeing compressive s 1 in addition to avoiding significant increase in strain inhomogeneity and pressing pressure. Fig. 7. Effect of choke angle of die exit channel on (a) variation of extrusion pressure and the variation of maximum principal stress at points (b) P1, (c) P2, and (d) P3. M. Torabi et al./Die Design Modification to Improve Workability.

show abstract

Section: Resultssupporting

confidence: 92%

Die Design Modification to Improve Workability during Equal Channel Angular Pressing

et al. 2016

View full text Add to dashboard Cite

show abstract

“…For example, in the ECAE process, the deformation zone moves along the workpiece when it passes through a die with angular channel. In this case, dead zones are formed at the edges of the workpiece [11][12][13][14][15][16][17][18][19][20][21]. Similar deformation conditions are realized during Twist Extrusion (TE) [5].…”

Section: Introductionmentioning

confidence: 99%

Development and FEM Modeling of a New Severe Plastic Deformation Process according to the Reverse Shear Scheme

Tarasov

Altukhov

Gribkov

et al. 2019

Modelling and Simulation in Engineering

View full text Add to dashboard Cite

Industrial commercial use of SPD processes is in some cases hindered by the complexity of equipment and high loads on the tool associated with high hydrostatics upon implementation of existing deformation processes. New and modified SPD schemes are offered relatively often, so the methods for their creation, modeling, and ways of improvement are of particular interest. Therefore, the article provides a classification of SPD schemes, which are divided into several groups depending on the nature of the material flow in the deformation zone. The second attribute of the fission process is the volume of the metal, contemporaneously located in the plastic deformation zone. An analysis of the influence of SPD schemes on the features of formation of a plastic deformation zone allows us to identify promising ways to modify them. A new SPD process is proposed, called as the “Reverse Shear” (RS), in which the workpiece is deformed under conditions of flat deformed state, uniform in each cross section along the entire length of the workpiece. The RS process allows us to change the paths of deformation to redistribute strain within the workpiece volume due to different positioning of a workpiece in a die. To justify the proposed deformation scheme, the SPD processes are divided into groups and an analysis of the deformation schemes’ features, which are analogs of RS, is performed. Simulation of the considered SPD processes was performed using FEM, implemented in specialized QForm CAE-system. A study of the influence of a tool with inclined surfaces on formation of a deformation zone in a workpiece during RS and analogues has been carried out. The degree of deformation nonuniformity in a cross section for the considered deformation schemes has been determined, and the possibilities of the proposed process are shown in comparison with analogues. The advantage of the RS scheme is the absence of unformed edges of the workpiece, which reduces material consumption, increasing the accumulated degree of deformation by one operation and reducing the tooling complexity to obtain workpieces with a desired structure. It also provides an opportunity to deform workpieces by various routes (RS-60 and RS-180) and to more specifically develop or select SPD schemes based on modeling. Changing the aspect ratio of the workpiece cross section also allows us to manage the change in its stress-strain state during deformation. Comparisons with the experiment carried out for three operations of deformation of a Cu-ETP copper sample by the RS-60 route show that the simulation results correspond to the real process.

show abstract

“…[80][81] Independently have reported research in the ECAE application of bevel edge 2θ0-punches to an angular extrusion through 2θ-dies (2θ0 = 2θ, 2θ ≠ 90°) in Perig et al's FEM-based [53], CFD-based [54,60], and circular gridlines-based [61] articles. Independently and simultaneously have appeared an alternative original research article by Nejadseyfi et al (2015Nejadseyfi et al ( -2016, which was focused on the application of an inclined 2θ0-punch to ECAE through an angular die with channel intersection angle with 2θ = 90° and punch inclination angle 2θ0 ≠ 2θ [43][44].…”

Section: Introductionmentioning

confidence: 99%

“…The purpose of the present research study is to provide an analysis of geometric and energypower parameters of Nejadseyfi et al's ECAE scheme [43][44] from CFD-based viewpoint [42, 46, 50-51, 54, 56-58, 60, 92-98].…”

Section: Introductionmentioning

confidence: 99%

Alternative Study of a Bevel Punch-Assisted Ecae Scheme

Perig

Golodenko

2018

Acta Metall Slovaca

View full text Add to dashboard Cite

It is a common practice in pressure forming to make an Equal Channel Angular Extrusion (ECAE) of a workpiece through a die with channel intersection angle 2θ = 90° using a standard punch of brick or cylindrical shape with 2θ0 = 90°. However Nejadseyfi et al (2015) have applied a beveled 2θ0-punch to the process of ECAE through a standard angular die of Segal geometry with 2θ = 90° and 2θ0 ≠ 2θ. The scope of the article is focused on an alternative numerical study of Nejadseyfi-ECAE-Scheme using techniques of Computational Fluid Dynamics (CFD). A finite-difference method was applied to the numerical solution of the boundary value problem for the Navier-Stokes equations in the form of a vorticity transfer equation. The complex of 2D plots for CFD-derived fields of flow lines and flow velocities and 3D plots for spatial distributions of flow velocities and tangential stresses were firstly derived for Nejadseyfi-ECAE-Scheme during viscous flow of polymer workpiece models through angular die with 2θ = 90° for the different punch inclination angles 30° ≤ 2θ0 ≤ 150°. It was found that Nejadseyfi-ECAE-Scheme provides enhancement of the rotary modes of intensive deformations during ECAE. Results provide visualization of velocity gradients and macroscopic rotation and the illustration of Nejadseyfi et al’s ideas from an alternative CFD-based viewpoint.

show abstract

Feasibility of attaining uniform grain structure and enhanced ductility in aluminum alloy by employing a beveled punch in equal-channel angular pressing

Cited by 8 publications

References 30 publications

Die Design Modification to Improve Workability during Equal Channel Angular Pressing

Die Design Modification to Improve Workability during Equal Channel Angular Pressing

Development and FEM Modeling of a New Severe Plastic Deformation Process according to the Reverse Shear Scheme

Alternative Study of a Bevel Punch-Assisted Ecae Scheme

Contact Info

Product

Resources

About