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 - load  - angle of transition of 2 channels  - angle of outside rounding of the channel R 1 – outer radius R 2 – inner radius b – channel width b 1 – channel width between roundings Fig. 2 Channel parametersFig. 1 Channel angles p

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 1 Pressure roller 2 Supporting insert Feed roller 34 Formed material Insert of forming tool 56 Fastening casing Fig. 4 CONFORM process

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 Fig. 6 Channel geometry Fig. 5 Pass - Fig. 5 Pass - type „B c “ ● Types of passes : - A, B a, B c, C

6. Parameters required for mathematical simulation ● Boundary conditions: - Tool temperature : T n = 20 and 350°C - Temperature of blank:T p = 20 and 350°C - Ambient temperature:T o = 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 Strain after the 1 st pass of the type B c Full section 50% of the section

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

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

11. Obtained values of Effective Plastic Strain in dependence on temperature, classical geometry of channel Temperature Pass „Bc“ 1.2.3.4. 20°C1.12.12.93.7 350°C1.052.12.93.6

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

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

14. Magnitude of deformation intensity of the alloy AlMn1Cu at 350°C and 4 passes, channel deflection 20° 1 st pass2 nd pass 3 rd pass 4 th pass Effective Plastic Strain

15. Obtained Values of Effective Plastic Strain in dependence on temperature, channel deflection 20° Temperature Pass „Bc“ 1.2.3.4. 20°C1.252.33.34.3 350°C1.252.33.44.3

16. Overall comparison of results Temperature / channel deflection Pass „Bc“ 1.2.3.4. 20°C1.152.12.93.7 350°C1.22.12.93.6 20°C / 20°- deflection1.252.33.34.4 350°C / 20° - deflection1.252.33.44.3 Obtained values of Effective Plastic Strain in dependence on temperature, channel geometry and number of passes

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

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 achieves 16-18% 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 d average = 250-300 nm, from the input grain size 20-30 mm.

19. Thank you for your attention