New Die Design Configuration for Grain Refinement by Hollow Twist Extrusion (HTE) Process

2020 ◽  
Author(s):  
J. Joudaki ◽  
M. Safari ◽  
S. M. Alhosseini
Keyword(s):  
Grain Refinement ◽  
Die Design ◽  
Twist Extrusion

Plastic Flow and Grain Refinement under Simple Shear-Based Severe Plastic Deformation Processing

2008 ◽  
Vol 604-605 ◽  
pp. 171-178 ◽  
Author(s):  
Dmitry Orlov ◽  
Yoshikazu Todaka ◽  
Minoru Umemoto ◽  
Yan Beygelzimer ◽  
Z. Horita ◽  
...  
Keyword(s):  
Grain Refinement ◽  
High Pressure Torsion ◽  
Equivalent Strain ◽  
Severe Plastic Deformation Processing ◽  
Structure Evolution ◽  
Twist Extrusion ◽  
High Purity Aluminum ◽  
Strain Reversal ◽  
Deformation Modes ◽  
Loading Scheme

In the present work, effects of loading scheme and strain reversal on structure evolution are studied by using high pressure torsion (HPT) and twist extrusion (TE) techniques. High purity aluminum (99.99%) was processed at room temperature up to a total average equivalent strain of ~4.8 by TE and HPT with two deformation modes: monotonic and reversal deformation with a step of 12˚ rotation. It was revealed that microstructural change with straining observed in pure Al was a common consequence of the SPD processing and was not affected significantly by the loading scheme. At the same time, it was found that strain reversal retarded grain refinement in comparison with monotonic deformation.

Die Design and Its Parameters for Grain Refinement of AA6XXX Series Through Equal Channel Angular Pressing

2021 ◽  
pp. 343-353
Author(s):  
Arshit Kapoor ◽  
Bhuwan Gupta ◽  
Abhishek Singhal ◽  
Krishna Mohan Agarwal
Keyword(s):  
Grain Refinement ◽  
Equal Channel Angular Pressing ◽  
Die Design ◽  
Angular Pressing

Grain Refinement in OFHC Cu Subjected to Repetitive Upsetting Extrusion (RUE) Process

2012 ◽  
Vol 710 ◽  
pp. 270-275 ◽  
Author(s):  
I. Balasundar ◽  
K.R. Ravi ◽  
T. Raghu
Keyword(s):  
Grain Refinement ◽  
Metal Forming ◽  
Large Deformations ◽  
Deformation Behaviour ◽  
Die Design ◽  
Powder Materials ◽  
Bulk Materials ◽  
Large Plastic Strain ◽  
Optical Scanning ◽  
Transmission Electron

Repetitive Upsetting Extrusion (RUE) is a relatively new severe plastic deformation (SPD) process in which two conventional metal forming operations such as upsetting and extrusion has been combined to impart large plastic strain. Though originally invented to process powder materials for bulk mechanical alloying, a more recent study on the process has revealed that by suitably modifying the die design, the process can be used to impart large deformations in bulk materials as well. Using this new die, oxygen free high conductivity (OFHC) copper has been subjected up to 10 cycles of RUE. Microstructures across the cross-section of the RUE processed samples were evaluated using optical, scanning and transmission electron microscope to ascertain the deformation behaviour and the mechanism of grain refinement. The results obtained are presented and discussed.

Grain Refinement of Pure Magnesium Using Nonlinear Twist Extrusion

2018 ◽  
Vol 939 ◽  
pp. 54-62 ◽  
Author(s):  
Muhammad Lutfi Maulidi ◽  
Hiroyuki Miyamoto ◽  
Motohiro Yuasa
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Bulk Material ◽  
Equivalent Plastic Strain ◽  
Pure Magnesium ◽  
Electron Backscattered Diffraction ◽  
Twist Extrusion ◽  
First Pass ◽  
Different Temperatures ◽  
Number Of Passes

Nonlinear Twist Extrusion (NTE) is a new severe plastic developed (SPD) method for producing grain refinement by extruding and twisting bulk materials through the channel designed for more effective straining compared with the so-called twist extrusion (TE). In this experiment pure magnesium was pressed using NTE for up to 4 passes. The pressing was conducted under two different temperatures, the first pass was conducted in 523K followed by pressing from 2 to 4 passes at 473K pressing temperature. The microstructure of the material is observed with increasing number of passes using optical microscopy (OM), laser microscope and scanning electron microscopy (SEM) electron backscattered diffraction (EBSD). Grain size decreased with increasing passes and become finer than those obtained by other SPD processing. If compared by the same equivalent plastic strain, and it suggests that NTE is a promising approach in strengthening bulk material. The grain size of the as-received material reduced from 97μm down to 3μm after 4 passes. Moreover, the hardness of material also increasing up to 41Hv for the first pass and constantly increased with the increasing number of pressing. This result shows that NTE is one of the promising methods in severe plastic deformation.

Twist Extrusion: Fundamentals and Applications

2010 ◽  
Vol 667-669 ◽  
pp. 31-37 ◽  
Author(s):  
Viktor Varyukhin ◽  
Yan Beygelzimer ◽  
R. Kulagin ◽  
O. Prokof'eva ◽  
Alexey Reshetov
Keyword(s):  
Grain Refinement ◽  
Equal Channel Angular Pressing ◽  
Simple Shear ◽  
Shear Layers ◽  
Powder Consolidation ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Specimen Axis ◽  
Twist Extrusion ◽  
Physical Effects

We present a study of the kinematics of Twist Extrusion (TE) and show that the mode of deformation in ТЕ is a simple shear. Unlike in Equal-Channel Angular Pressing (ECAP), there are two main shear layers perpendicular to the specimen axis. TE has a significant commercial potential due to the following physical effects: intensive grain refinement; homogenization and mixing; intensive powder consolidation. Donetsk Institute for Physics and Engineering created a TE Center to showcase the process and educate investors. Our experience with the center has shown that the most prospective directions are producing ultrafine-grained (UFG) alloys for medical and aircraft applications.

Grain refinement response during twist extrusion of an Al-0.13% Mg alloy

2007 ◽  
Vol 98 (3) ◽  
pp. 200-204 ◽  
Author(s):  
Marco Berta ◽  
Dmitry Orlov ◽  
Philip B. Prangnell
Keyword(s):  
Grain Refinement ◽  
Mg Alloy ◽  
Twist Extrusion

A new upper bound solution for the analysis of the twist extrusion process with an elliptical die cross-section

2009 ◽  
Vol 223 (9) ◽  
pp. 1975-1981 ◽  
Author(s):  
Salehi M Seyed ◽  
S Serajzadeh
Keyword(s):  
Upper Bound ◽  
Extrusion Process ◽  
Die Design ◽  
Design Parameters ◽  
Element Analysis ◽  
Die Geometry ◽  
Proposed Model ◽  
Twist Extrusion ◽  
Upper Bound Technique ◽  
Highly Strained

The twist extrusion process is a rather new route to produce highly strained materials. In this process, severe plastic deformation is applied by large shear strains. In this regard, prediction of materials behaviour and extrusion pressure is of importance to die designers and engineers. In this article, utilizing an admissible velocity field together with the upper bound technique, the required energy for twist extrusion is predicted. The proposed model is capable of considering the effect of various parameters such as die geometry and friction conditions. In addition, the model anticipates the critical die design parameters. To verify the proposed model, the predictions are compared with the results of a finite-element analysis and reasonable consistency is observed.

Twist Extrusion as a Tool for Grain Refinement in Al-Mg-Sc-Zr Alloys

2006 ◽  
pp. 77-82 ◽  
Author(s):  
D. Orlov ◽  
A. Reshetov ◽  
A. Synkov ◽  
V. Varyukhin ◽  
D. Lotsko ◽  
...  
Keyword(s):  
Grain Refinement ◽  
Twist Extrusion ◽  
Zr Alloys

Grain Refinement in Titanium-Erbium Alloys

1974 ◽  
Vol 32 ◽  
pp. 522-523
Author(s):  
B. B. Rath ◽  
J. E. O'Neal ◽  
R. J. Lederich
Keyword(s):  
Electron Microscopy ◽  
Size Distribution ◽  
Grain Refinement ◽  
Grain Growth ◽  
Volume Fraction ◽  
Pure Titanium ◽  
Systematic Investigation ◽  
Second Phase ◽  
Titanium Matrix ◽  
Average Size

Addition of small amounts of erbium has a profound effect on recrystallization and grain growth in titanium. Erbium, because of its negligible solubility in titanium, precipitates in the titanium matrix as a finely dispersed second phase. The presence of this phase, depending on its average size, distribution, and volume fraction in titanium, strongly inhibits the migration of grain boundaries during recrystallization and grain growth, and thus produces ultimate grains of sub-micrometer dimensions. A systematic investigation has been conducted to study the isothermal grain growth in electrolytically pure titanium and titanium-erbium alloys (Er concentration ranging from 0-0.3 at.%) over the temperature range of 450 to 850°C by electron microscopy.

Sign in / Sign up

Export Citation Format

Share Document