Metallurgical and Materials Transactions A

, Volume 44, Issue 3, pp 1519–1529

Recrystallization Phenomena During Friction Stir Processing of Hypereutectic Aluminum-Silicon Alloy

  • A. G. Rao
  • K. R. Ravi
  • B. Ramakrishnarao
  • V. P. Deshmukh
  • A. Sharma
  • N. Prabhu
  • B. P. Kashyap
Article

DOI: 10.1007/s11661-012-1489-6

Cite this article as:
Rao, A.G., Ravi, K.R., Ramakrishnarao, B. et al. Metall and Mat Trans A (2013) 44: 1519. doi:10.1007/s11661-012-1489-6

Abstract

Microstructural evolution and related dynamic recrystallization phenomena were investigated in overlapping multipass friction stir processing (FSP) of hypereutectic Al-30 pct Si alloy. FSP resulted in the elimination of porosities along with the refinement of primary silicon particles and alpha aluminum grains. These alpha aluminum grains predominantly exhibit high angle boundaries with various degrees of recovered substructure and dislocation densities. The substructure and grain formation during FSP take place primarily by annihilation and reorganization of dislocations in the grain interior and at low angle grain boundary. During multipass overlap FSP, small second phase particles were observed to form, which are accountable for pinning the grain boundaries and thus restricting their growth. During the multipass overlap FSP, the microstructure undergoes continuous dynamic recrystallization by formation of the subgrain boundary and subgrain growth to the grain structure comprising of mostly high angle grain boundaries.

Copyright information

© The Minerals, Metals & Materials Society and ASM International 2012

Authors and Affiliations

  • A. G. Rao
    • 1
    • 2
  • K. R. Ravi
    • 3
  • B. Ramakrishnarao
    • 2
  • V. P. Deshmukh
    • 2
  • A. Sharma
    • 4
  • N. Prabhu
    • 1
  • B. P. Kashyap
    • 1
  1. 1.Department of Metallurgical Engineering and Materials ScienceIndian Institute of Technology, BombayMumbaiIndia
  2. 2.Marine Materials DivisionNaval Materials Research LaboratoryAmbernath (East)India
  3. 3.Nanotech Research FacilityPSG Institute of Advanced StudiesCoimbatoreIndia
  4. 4.Department of Mechanical EngineeringIndian Institute of Technology, BombayMumbaiIndia