Equal Channel Angular Extrusion Grain refinement by severe deformation and FEA of ECAE deformation was carried out using Hyper mesh, Abaqus for optimization of Billet. Tasks Performed Effect of friction on Strain Effect of die angle on Strain Effect of Fillet radius on Strain Effect of Thickness on Strain

1. Design of Equal Channel
Angular Extrusion For
Grain Refinement
MANUFACTURING PROCESSING TECHNIQUES
Pratik Saxena – GD8959

2. Outline
 Introduction
 Problem Statement
 Objectives
 Literature Review
 Results
 Conclusions/Recommendations
 References
2

3. What is ECAE?
 An extrusion technique used
to refine the microstructure
of metals and alloys, which
increases their strength.
 Developed first in Soviet
Union (now Russia), in the
early 1990s.
 Cold working process.
 Strain hardening achieved
without reduction in Cross
Sectional Area.

4. Introduction 4
► Equal-channel angular extrusion(ECAE) is a processing procedure in
which a sample, generally in the form of a rod or bar, is pressed
through a die constrained within a channel which is bent through a
sharp angle near the center of the die.
► Sample emerges from the die having experienced a high shearing
strain but without any change in the cross-sectional dimension.
► The shear deformation of the specimen occurs at the intersection of
the contact area between the channels.
► The repeated procedure is repeated ECAP the systematic increase of
deformation, leading to consistent reduction in grain size due to the
formation of low-angle grid first, and then the high angle boundaries.

5. Problem Statement
Grain refinement by severe deformation and FEA of ECAE
deformation, and provide a design guideline by FEA simulation to
obtain the following results:
 Task 1: Establishing a relationship between friction coefficient m (=0.0, 0.06,
0.08, 0.1 and 0.2) and plastic strain per pass, and the uniformity of strain
over the extruded sample.
 Task 2 :The effect of channel geometry on plastic deformation for
rectangular shape. What will happen if the angle is not 90º, but 120º? Will
this reduce the strain per pass and also reduce the extrusion pressure?
Without considering its effect on grain refinement, estimate the strain per
unit work from the extrusion force.
 Task 3: What will happen if the radius of corner fillet is 0.0, 0.5 or 1.0 mm?
 Task 4: The effect of width-to-thickness ratio on ECAE processes. Perform
simulation of 2D extrusion model with different thickness (1, 5, 10) while
friction coefficient keeps the same as 0.08. Build one 3D modeling, perform
simulation and compare the results with 2D case.
 Task 5: The effect of temperature on ECAE processes.
5

6. Literature Review
 Journal of Pregaman “AN EXPERIMENTAL STUDY OF EQUAL
CHANNEL ANGULAR EXTRUSION” by Baker, Y.W.a.I 1996-1997
 Experimental Data was analyzed by jig design for die with different
angles
 Die with 120 angle has smaller shear deformation than 90
 Effect of equal channel angular pressing on microstructure and
mechanical properties of commercial purity aluminum. by Manna,
R., N.K. Mukhopadhyay, and G.V.S. Sastry, 2008.
 Shear deformation was clearly observed on Y plane
 Shear deformation near the surface which pass through the inner
corner of the die is very uniform while that near the surface which pass
through the outer corner of the die in not uniform
 Aidang Shan, I.-G.M., 2 Hung-Suk Ko,2 and Jong-Woo Park2,
DIRECT OBSERVATION OF SHEAR DEFORMATION DURING EQUAL
CHANNEL ANGULAR PRESSING OF PURE ALUMINUM. 1999
6

7. Objectives
 To perform FEA with Abaqus/standard or dynamic
methods for optimal process design.
 The optimization of the process is defined by the
maximization of strain localization, or to achieve a
maximal plastic strain per pass.
7

8. FEA Procedure
 Material, property and component cards were created.
 Geometry of the billet was defined. 2D mesh with element size
0.2 was generated using spline command. Element type used
was CPE4R.
 Contact definitions were created. For modeling die, two
analytically rigid walls were created along die surfaces and
contact was defined between walls and billet surface.
 To simulate the extrusion, displacement in negative “Y” direction
was given to top surface of the billet.
 Analytical rigid were fixed with respect to ground.
 Output block was created. Load step was defined.
 Analysis was submitted to run in ABAQUS-CAE.
8

9. FEA Procedure

9
FEA Model with 90 °
Die Angle
FEA Model with 120 °
Die Angle

10. Results: Task 1: Effect of friction on Strain
 The strain value is linearly increasing with the increase in friction coefficient.
 The effective plastic strain distribution along the billet middle portions induced an
extended deformation plastic zone.
 The other important effect of friction is to change the degree to which the dies
internal corner is filled and the magnitude of the shear developed within the
homogeneous deformed section of the specimen.
 Reduction of the intensity of the shear strain per pass.
10
Sr. No. Fillet radius Friction Maximum Strain
1 0.5 0 2.09
2 0.5 0.06 2.2
3 0.5 0.08 2.24
4 0.5 0.1 2.27
5 0.5 0.2 2.641

11. Results: Task 1: Effect of friction on Strain
11
μ= 0.0
μ= 0.06
μ= 0.1 μ= 0.2
μ= 0.08
2.09 2.2 2.24 2.27
2.641
0
1
2
3
0 0.05 0.1 0.15 0.2 0.25
STRAIN
COEFFICIENT OF FRICTION
STRAIN

12. Results:Task2: Effect of die angle on Strain
 Modeling was carried out with the 120° die using two values of friction on the
sliding surfaces between the billet and the die. The internal die corners were
assumed with fillet radius=1mm.
 The results of this model were compared to previous finite element results
obtained using the same methodology with a 90° die, for same friction
coefficients.
 With both die angles, when there is low friction and no back-pressure, it can be
seen that the shear strain is very inhomogeneous. It increases for 40% of the
sample width for the 120° die. With the 90° die it behaves similarly, but reaches a
stable level at about 30% of the billet width as shown in fig 10.
 There is a substantial improvement in the strain homogeneity across the billet
width for the extrusions carried out under the higher friction conditions.
12
Sr. No.
Die
Angle
Maximum
Strain
1 90 2.234
2 120 0.7

13. 13
Die angle = 90°
Results:Task2: Effect of die angle on Strain
0
0.5
1
1.5
2
2.5
80 85 90 95 100 105 110 115 120 125
Strain
Die Angle
Effect of Die Angle on Plastic Strain
Die angle = 120°

14. Results:Task3 Effect of Fillet radius on Strain
 Low values of fillet radius would tend to prevent the spread of deformation away
from the shear zone, thus promoting a more localized form of shear flow.
 Simultaneously, the occurrence of strain hardening and a small to medium amount
of strain-rate hardening would be expected to prevent noticeably unstable shear
concentration.
 The deformation homogeneity caused by fillets of the outer corner is larger than
that induced by the ECAE dies without outer corner fillets from the simulation,
because fillet at the inner channel surface junction where the two straight channels
meet helps to process materials with high percentage of flow softening.
 Hence as the radius increases the plastic strain decreases.
14
Sr. No. Fillet radius Maximum Strain
1 0.5 2.532
2 1 2.08
3 2 1.617

15. Results:Task3 Effect of Fillet radius on
Strain 15
0
1
2
3
0 0.5 1 1.5 2 2.5
Strain
Fillet Radius
Effect of Fillet radius on Plastic Strain
r = 0.5mm
r = 1mm
r = 2mm

16. Results:Task4 Effect of Thickness on Strain
 As the thickness increases, the strain in different models was exactly same.
 Thus we can Say that there is no effect of thickness on the equivalent plastic strain.
16
Sr. No. Thickness Maximum Strain
1 1 2.24
2 5 2.24
3 10 2.24
0
0.5
1
1.5
2
2.5
0 1 2 3 4 5 6 7 8 9 10 11 12
Strain
Thickness
Effect of Thickness on Plastic Strain

17. 1mm Thickness 5mm Thickness
10mm Thickness
17

18. Results:Task5 Effect of Temperature on
Strain
 To investigate the temperature effect, the test is carried out in four different
temperatures; 20° C, 50° C, 100° C and 150° C .
 Increase in temperature reduces the difference among grain sizes during the
initial passes which mean grain refinement efficiency reduces because of
recrystallization.
 Also, due to increase in temperature, the stresses and strain values increase as
the material is subjected to thermal stresses as well.
 Low values of fillet radius would tend to prevent the spread of deformation away
from the.
18
Sr. No. Temperature
Maximum
Strain
1 20 2.08
2 50 2.172
3 100 2.322
4 150 2.56

19. PEEQ Contour for
Temperature 200 C
Stress-strain curve for
Temperature 200 C

20. PEEQ Contour for
Temperature 500 C
Stress-strain curve for
Temperature 500 C

21. PEEQ Contour for
Temperature 1000 C
Stress-strain curve for
Temperature 1000 C

22. PEEQ Contour for
Temperature 1500 C
Stress-strain curve for
Temperature 1500 C

23. Results:Task5 Effect of Temperature on Strain 23
Temperature= 20°C Temperature= 50°C
Temperature= 100°C Temperature= 150°C

24. Conclusions & Recommendations
Conclusions
• The strain value is linearly increasing with the increase in friction coefficient.
• Based on the CAE results it seems that there was no significant change in strain
level with the change in friction coefficients.
• The strain per pass and the extrusion pressure are considerably lesser in the
120 degree model as compared to the 90 degree.
• Adding a fillet and increasing the radius reduces the strain introduced through
extrusion.
• The Strain remains constant from 1mm to 5 mm to 10mm
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25. References
1. Duan, Z.C. and T.G. Langdon, An experimental evaluation of a special ECAP die containing two equal arcs of
curvature. Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing, 2011.
528(12): p. 4173-4179.
2. Segal, V.M., Materials processing by simple shear. (A197 (1995) 157 164).
3. Manna, R., N.K. Mukhopadhyay, and G.V.S. Sastry, Effect of equal channel angular pressing on microstructure and
mechanical properties of commercial purity aluminum. Metallurgical and Materials Transactions a-Physical Metallurgy
and Materials Science, 2008. 39a(7): p. 1525-1534.
4. P.B. Prangnell’, C.H.p.a.S.M.R., FINITE ELEMENT MODELLING OF EQUAL CHANNEL ANGULAR EXTRUSION. 1997. PII
S1359-6462(97)00192-9.
5. Aidang Shan, I.-G.M., 2 Hung-Suk Ko,2 and Jong-Woo Park2, DIRECT OBSERVATION OF SHEAR DEFORMATION
DURING EQUAL CHANNEL ANGULAR PRESSING OF PURE ALUMINUM. 1999. PII S1359-6462(99)00188-8.
6. Baker, Y.W.a.I., AN EXPERIMENTAL STUDY OF EQUAL CHANNEL ANGULAR EXTRUSION 1996-1997(PI1 S1359-
6462(97)00132-).
7. Ghazani, M.S. and B. Eghbali, Finite element simulation of cross equal channel angular pressing. Computational
Materials Science, 2013. 74: p. 124-128.
8. Ebrahimi, M., et al., Experimental Investigation of the Equal Channel Forward Extrusion Process. Metals, 2015. 5(1): p.
471-483.
9. Horita, Z., T. Fujinami, and T.G. Langdon, The potential for scaling ECAP: effect of sample size on grain refinement and
mechanical properties. Materials Science and Engineering a-Structural Materials Properties Microstructure and
Processing, 2001. 318(1-2): p. 34-41.
10. Sepahi-Boroujeni, S. and F. Fereshteh-Saniee, Expansion equal channel angular extrusion, as a novel severe plastic
deformation technique. Journal of Materials Science, 2015. 50(11): p. 3908-3919.
11. Djavanroodi, F., et al., Equal Channel Angular Pressing of Tubular Samples. Acta Metallurgica Sinica-English Letters,
2013. 26(5): p. 574-580.
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26. Thank You
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