S. Rusz, K. Malanik, J. Kedroň

1. NANO Ostrava 2008(1 – 4. 9. 2008)Refining of structure of the alloy AlMn1Cu with use of multiple severe plastic deformation S. Rusz, K. Malanik, J. Kedroň VSB – Technical university of Ostrava, Faculty of Mechanical Engineering, Czech Republic VUHZ Dobra a. s. , Czech Republic

2. Principle of the Equal Channel Angular Pressing(ECAP) p Fig. 1 Channel angles Fig. 2 Channel parameters R1 – outer radius R2 – inner radius b – channel width b1 – channel width between roundings p - load  - angle of transition of 2 channels  - angle of outside rounding of the channel

3. Mathematical simulation of the SPD process ●Existing state of development of simulation 3D simulation of extrusion by the ECMAP process Fig. 3 Obtained amount of deformation for 3 types of passes

4. 1 2 3 4 5 6 Fig. 4 CONFORM process 1 Pressure roller 2 Supporting insert 3 Feed roller 4 Formed material 5 Insert of forming tool 6 Fastening casing

5. Principle of the ECAP technology ●Channel parameters: R1 – outer radius R2 – inner radius Ø – inside angle of 2 channels Ψ – angle of rounding of the outer channel b – channel width p - load ●Types of passes : - A, Ba, Bc, C Fig. 5 Pass - type „Bc“ Fig. 6 Channel geometry

6. Parameters required for mathematical simulation ●Boundary conditions: - Tool temperature : Tn = 20 and 350°C - Temperature of blank: Tp = 20 and 350°C - Ambient temperature: To = 20°C - Tool material: SKD 61 - Material of sample: AlMn1Cu - Friction coefficient: f = 0.1 - Rate of extrusion: v = 0.5 mm/s Fig. 7 ECAP tool arrangement

7. Simulation of the ECAP process – alloy AlMn1Cu R1 = 4 mm R2 = 0.5 mm b = 10 mm Ø = 90° Ψ = 90° Fig. 8 Design of suitable forming tool geometry

8. Effective Plastic Strainafter the 1st pass of the type Bc 50% of the section Full section

9. Effective Plastic Strain of the alloy AlMn1Cu at 20°C and 4 passes Effective Plastic Strain Effective Plastic Strain 2nd pass 1st pass Effective Plastic Strain Effective Plastic Strain 3rd pass 4th pass

10. Effective Plastic Strain of the alloy AlMn1Cu at 350°C and 4 passes Effective Plastic Strain Effective Plastic Strain 2nd pass 1st pass Effective Plastic Strain Effective Plastic Strain 4th pass 3rd pass

11. Obtained values of Effective Plastic Strain independence on temperature, classical geometry of channel

12. Modification of tool geometry for increased amount of deformation Channel geometry R1 = 4 mm R2 = 0.5 mm R3 = 5 mm b = 10 mm Ø = 90° Ψ = 90° Fig. 9ECAP tool with deflection of 20°

13. Effective Plastic Strain of the alloy AlMn1Cu at 20°C and 4 passes, channel deflection 20° Effective Plastic Strain Effective Plastic Strain 1st pass 2nd pass Effective Plastic Strain Effective Plastic Strain 3rd pass 4th pass

14. Magnitude of deformation intensity of the alloy AlMn1Cu at 350°C and 4 passes, channel deflection 20° Effective Plastic Strain Effective Plastic Strain 1st pass 2nd pass Effective Plastic Strain Effective Plastic Strain 4th pass 3rd pass

15. Obtained Values of Effective Plastic Strain in dependence on temperature, channel deflection 20°

16. Overall comparison of results Obtained values of Effective Plastic Strain in dependence on temperature, channel geometry and number of passes

17. Metallographic analysis on AFM microscope a)b) Fig. 10 Microstructural analysis a) after the 3rd pass b) after the 4th pass through the ECAP tool

18. Conclusion ● Growth of deformation intensity was obtained at extrusion of sample alloys through the ECAP tool after multiple passes. In conformity with theoretical assumptions greater number of passes results in substantial growth. ●No influence of temperature on obtained deformation intensity was detected after individual passes. ● Modified tool geometry aimed at increase of the value of effective plastic strain (20° offset of horizontal part of the channel)enabled substantial increase of sample deformation already after the first pass and subsequent passes through the ECAP tool, which contributes significantly to enhancement of the SPD process efficiency. This value achieves16-18% of growth in individual passes. ● According to the input analysis of microstructure of extruded samples the process brought substantial refinement of grain to the final size daverage= 250-300 nm, from the input grain size 20-30 mm.

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