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Title: The effect of postprocessing on tensile property and microstructure evolution of friction stir welding aluminum alloy joint

Friction stir welding is an efficient manufacturing method for joining aluminum alloy and can dramatically reduce grain size conferring excellent plastic deformation properties. Consequently, friction stir welding is used to manufacture tailor welded blanks to optimize weight or performance in the final component. In the study, the microstructural evolution and mechanical properties of friction stir welding joint during plastic forming and subsequent heat treatment were investigated. The microstructural characteristics of the friction stir welding joints were studied by Electron Backscattered Diffraction and Transmission Electron Microscopy. The mechanical properties were evaluated by tensile and microhardness tests. It is found that the tensile and yield strengths of friction stir welding joints are significantly improved after severe plastic deformation due to the grain refinement. Following heat treatment, the strength of the friction stir welding joints significantly decrease due to the obvious abnormal grain growth. Careful attention must be given to the processing route of any friction stir welding joint intended for plastic forming, especially the annealing between forming passes. Severe plastic deforming of the friction stir welding joint leads to a high level of stored energy/dislocation density, which causes the abnormal grain growth during subsequent heat treatment, and consequently reduce the mechanical propertiesmore » of the friction stir welding joint. - Highlights: • Great changes are observed in the microstructure of FSW joint after postprocessing. • Postprocessing shows great effect on the microstructure stability of FSW joint. • The weld shows more significant decrease in strength than the BM due to the AGG. • Attention must be given to the processing route of FSW joint for plastic forming.« less
Authors:
 [1] ;  [2] ;  [2] ;  [3] ;  [4] ; ; ;  [1]
  1. Hubei Key Laboratory of Advanced Technology of Automobile Parts, Wuhan University of Technology, Wuhan 430070 (China)
  2. (China)
  3. State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China)
  4. School of Mechanical and Electrical Engineering, Wuhan Donghu University, Wuhan 430070 (China)
Publication Date:
OSTI Identifier:
22476017
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 99; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM ALLOYS; ANNEALING; DENSITY; DIFFRACTION; DISLOCATIONS; FRICTION; GRAIN GROWTH; GRAIN REFINEMENT; GRAIN SIZE; MICROHARDNESS; PERFORMANCE; PLASTICITY; STABILITY; STORED ENERGY; TRANSMISSION ELECTRON MICROSCOPY; WELDED JOINTS; WELDING; YIELD STRENGTH