Friction Stir Processing of Aluminum Alloy

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Friction Stir Processing of Aluminum Alloy

• Renée Gordon
• Adv Microstructure Analysis
• Dr. A.D. Rollett
• Dr. P.N. Kalu

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Friction Stir Processing (FSP)

• Developed in 1991 at The Welding Institute of the
  United Kingdom
• A rotating cylindrical pin tool with a shoulder
  of larger diameter plunges into material
• Once shoulder of tool touches material surface,
  tool is traversed along weld line

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Friction Stir Processing

• Solid-state process
• Material is softened by Frictional Heat
• Temperature below melting point
• Process has characteristic microstructure that is
  dependent on
• Load (axial force)
• Pin and shoulder diameter
• Tilt angle

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Friction Stir Processing

• Example where microstructure varies based on
  applied load
• As load is increased defects are eliminated

Arrows indicate presence of voids in welded
material.
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Friction Stir Processing

• Three distinct microstructural zones are
  generated
• Stir zone (SZ)
• Thermo mechanically affected zone (TMAZ)
• Heat affected zone (HAZ)

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Friction Stir Processing

• Variation in microstructure
• SZ
• TMAZ
• HAZ
• Stir zone has finer grain size
• Random orientation of grain boundaries

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Orientation Imaging Microscopy (OIM)

• Friction Stir Processed AA5052 (1 pass)
• Tool rotation rate 500 rpm
• Traverse speed 2 ipm (inches per minute)
• Center of the Stir Zone

• As received AA5052
• Directional Orientation

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Motivation of Study

• Elimination of defects within microstructure of
  stir zone
• Strength and ductility improves
• Increases resistance to fatigue
• Has potential to form superplasticity through
  fine grain microstructure
• Cost Efficient
• Reliable

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Future Work

• Characterize AA5083
• Electron Backscattered Diffraction (EBSD)
• OIM
• Analyze microstructural zones
• Model the effects of FSP on the microstructure

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References

• Y. Wang, R.S. Mishra, Materials Science and
  EngineeringA, Volume 463, Issues 1-2, August
  2007.
• W.M. Thomas, E.D. Nicholas, J.C. Needham, M.G.
  Murch, P. Templesmith, C.J. Dawes, GB Patent
  Application No. 9125978.8, December 1991.
• T.R. McNelley, S. Swaminathan, J.Q. Su, Scripta
  Materialia, Volume 58, Issue 5, March 2008.
• S. Mironov, Y.S. Sato, H. Kokoawa, Acta
  Materialia, March 2008.

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• THANK YOU