Possibilities Of Possibilities Of Aluminium Extrusion Aluminium Extrusion By The ECAP MethodBy The ECAP Method

Miroslav Greger - VŠB – Miroslav Greger - VŠB – Technical University Technical University oof Ostravaf Ostrava

Stanislav Rusz - VŠB – Stanislav Rusz - VŠB – Technical University Technical University oof f OstravaOstrava

IntroductionIntroduction

The technology ECAP allows to The technology ECAP allows to obtain an ultra-fine grain in larger obtain an ultra-fine grain in larger volumes,volumes, moreover without change moreover without change of original cross-section of the input of original cross-section of the input

semi-product.semi-product. It is possible to use It is possible to use the obtained materials in automotive the obtained materials in automotive industry, in military and aerospace industry, in military and aerospace

industries.industries.

Principles Principles oof ECAPf ECAP

Fig. 1. Schematic illustration of equal channel Fig. 1. Schematic illustration of equal channel angular pressing angular pressing process process (ECAP)(ECAP)

Principles Principles oof Shearing f Shearing oon n Passage Passage TThrough hrough tthe ECAP Diehe ECAP Die

Route A

Route BA

Route C

Route BC

90°

180°

90°

Fig. 2. The four processing routes in ECAPFig. 2. The four processing routes in ECAP

Shearing Patterns Associated Shearing Patterns Associated wwith ith tthe Different Processing he Different Processing

RoutesRoutes

Fig. 3. Shearing associated Fig. 3. Shearing associated byby a single passage a single passage through the diethrough the die

X

Y

Z

Y

Z

X

Z plane

Y plane

X plane

Influences of the Forming Influences of the Forming Parameters on Plastic Parameters on Plastic

DeformationDeformation

Influence of inner energyInfluence of inner energy Non-homogeneity of deformationNon-homogeneity of deformation Density of dislocationDensity of dislocation Concentration of vacanciesConcentration of vacancies

Change Change oof Dislocation f Dislocation SubstructureSubstructure

Fig. 4. Scheme of change of dislocation sub-Fig. 4. Scheme of change of dislocation sub-structure after cold deformationstructure after cold deformation

DependenciesDependencies

0K

0 dislocation density

constant

size of deformation

K

Linear dependence of Linear dependence of dislocation density:dislocation density:

Flow stress necessary for continuing of Flow stress necessary for continuing of deformation:deformation:

1

20 k G b

0 value of init. flow stress

k constant

, modulus of elasticity in shear,

Burger's vector

G b

Experimental Experimental VVerificationerification

Fig. 5. Overall view on Fig. 5. Overall view on the forming equipment the forming equipment

and dieand die

Fig. 6. Detailed view oFig. 6. Detailed view onn the extruding punch for the extruding punch for

the ECAP technologythe ECAP technology

Samples Samples ffor Extrusionor Extrusion

Fig. 7. Initial sample Fig. 7. Initial sample and samples after and samples after

extrusionextrusion

Fig. 8. Structure in the Fig. 8. Structure in the central areacentral area

50 m

Deformation ResistanceDeformation Resistance

Fig. 9. Deformation Fig. 9. Deformation resistance of the resistance of the

aluminiumaluminium

Fig. 10. Deformation Fig. 10. Deformation resistance of the alloy resistance of the alloy

AlCuMgAlCuMg

Micro-structure Micro-structure oof Sample f Sample After ExtrusionAfter Extrusion

Fig. 11. The first Fig. 11. The first passagepassage

Fig. 14. The fourth Fig. 14. The fourth passagepassage

50 m

50 m

Fig. 13. The third Fig. 13. The third passagepassage

Fig. 12. The second Fig. 12. The second passagepassage

ConclusionConclusion

Refining of grain in poly-crystalline metals.Refining of grain in poly-crystalline metals. Micro-structure obtained by ECAP method Micro-structure obtained by ECAP method

depends on:depends on: Using of more passes and turning of the sample.Using of more passes and turning of the sample. Extruding the sample by 4 or more passes.Extruding the sample by 4 or more passes.

Optimal angle between horizontal and vertical Optimal angle between horizontal and vertical channel of the part is ≈ 90 degrees. Radius of fillet channel of the part is ≈ 90 degrees. Radius of fillet of the extrusion channel must correspond to of the extrusion channel must correspond to conditions for steady flow of metal.conditions for steady flow of metal.

Strain rate has only partial influence on Strain rate has only partial influence on deformation resistance and small influence on deformation resistance and small influence on micro-structure.micro-structure.

Practical Illustration Practical Illustration oof f tthe he ECAP MethodECAP Method by by

Mathematic Modeling Mathematic Modeling

Fig. 15. The example of stress intensity by Fig. 15. The example of stress intensity by the the simulation process of the AlCuMg extrusion simulation process of the AlCuMg extrusion (1st and 2nd sample)(1st and 2nd sample)

Practical Illustration Practical Illustration oof f tthe he ECAP MethodECAP Method by by Mathematic Mathematic

ModelingModeling

Fig. 16. The example Fig. 16. The example of of shear stresses shear stresses ppartition artition byby the the ECAP method (1st a 2nd sample)ECAP method (1st a 2nd sample)

Practical Illustration Practical Illustration oof f tthe he ECAP MethodECAP Method by by Mathematic Mathematic

ModelingModeling

Fig. 17. Contact pressure between sample and Fig. 17. Contact pressure between sample and tools tools for for AlCuMg alloy by the ECAP methodAlCuMg alloy by the ECAP method (1st a (1st a 2nd sample)2nd sample)

Practical Illustration Practical Illustration oof f tthe he ECAP MethodECAP Method by by

Mathematic ModelingMathematic Modeling

Fig. 18. Fig. 18. The example of the dThe example of the deformation intensity eformation intensity ofof AlCuMg AlCuMg alloyalloy by the ECAP method (1st a 2nd by the ECAP method (1st a 2nd sample)sample)

Practical Illustration Practical Illustration oof f tthe he ECAP MethodECAP Method by by Mathematic Mathematic

ModelingModeling

Fig. 19. The Fig. 19. The exexample of the lay-out of ample of the lay-out of temperature of AlCuMg alloy by the ECAP temperature of AlCuMg alloy by the ECAP method (1st a 2nd sample)method (1st a 2nd sample)

Thank you for your attentionThank you for your attention