J. Mater. Sci. Technol. ›› 2010, Vol. 26 ›› Issue (8): 747-753.

• Research Articles • 上一篇    下一篇

Microstructure evolution during friction stir welding of AA 2219

Kanwer Singh Arora1,Sunil Pandey2,Michael Schaper3,Rajneesh Kumar4   

  1. 1. Forschungzentrum Dresden-Rossendorf
    2. IndianInstitute of Technology, Delhi
    3. Institute of Materials Science
    4. National Metallurgical Laboratory
  • 收稿日期:2009-12-21 修回日期:2010-04-04 出版日期:2010-08-28 发布日期:2010-08-23
  • 通讯作者: Kanwer Singh Arora

Microstructure Evolution during Friction Stir Welding of Aluminum Alloy AA2219

K.S. Arora1,2,4), S. Pandey1), M. Schaper2), R. Kumar3)   

  1. 1) Mechanical Engineering Department, Indian Institute of Technology, Delhi-110016, India
    2) Institut fuer Werkstoffwissenschaft, Technische Universitaet Dresden, Dresden-01069, Germany
    3) Engineering Division, National Metallurgical Laboratory, Jamshedpur-831007, India
    4) Institut fuer Sicherheitsforschung, Forschungszentrum Dresden-Rossendorf, Dresden-01328, Germany
  • Received:2009-12-21 Revised:2010-04-04 Online:2010-08-28 Published:2010-08-23
  • Contact: K.S. Arora

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摘要：

Characterization of microstructure evolution in friction stir welded 2219-T87 was carried out by optical and transmission electron microscopy and electron back scatter diffraction. Weld nugget consisted of very fine equiaxed grains and experienced dissolution of nearly half of metastable precipitates into the matrix during welding. TMAZ also experienced dissolution of precipitates but to a lesser extent whereas coarsening of precipitates was observed in HAZ. Grain boundary misorientation measurements using EBSD indicated towards continuous dynamic recrystallization as the underlying mechanism behind the fine equiaxed nugget grains. The yield and tensile strength of the weld decreased with comparison to base material. But on account of decreased grain size and dissolution of second phase precipitates, an increased charpy energy value was observed in the weld nugget.

Abstract:

The characterization of microstructure evolution in friction stir welded aluminum alloy was carried out by optical microscopy (OM) and transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD). The weld nugget consisted of very fine equiaxed grains and experienced dissolution of nearly half of metastable precipitates into the matrix during welding. Thermomechanically affected zone (TMAZ) also experienced dissolution of precipitates but to a lesser extent whereas coarsening of precipitates was observed in heat affected zone (HAZ). Grain boundary misorientation measurements using EBSD indicated continuous dynamic recrystallization as the underlying mechanism for the fine equiaxed nugget grains. The yield and tensile strength of the weld decreased with comparison to base material. But due to the decrease of grain size and the dissolution of second phase precipitates, an increased Charpy energy value was observed in the weld nugget.

Key words: Friction stir welding, AA2219, Precipitates, Vickers hardness, Tensile testing, Charpy impact energy