Effect of physical variables in dynamic recrystallization during friction stir welding of aluminum alloy

  Haftu Hagazi Hadgu

Tailoring microstructure in single pass or multipass deformation process is one of the cutting edge research areas in several applications of engineering problems. An accurate knowledge of the overall temperature distribution, strain and strain rate are prerequisites for reliable prediction of final microstructure and mechanical properties of the deformed products. One typical application of heavily deformed process is observed in friction stir welding (FSW) which is one of the emerging solid state joining processes where the material is processed by extreme plastic deformation associated with the frictional straining. FSW is subjected to variable temperature, strain and strain rate at different zones of welded sample. The domain of interest passes through variable range of physical parameters i.e. temperature, strain and strain rate. Also the variability exists due to different process parameters like tool rotational speed, welding speed and additional external heat source of hybrid FSW process. The recrystallization kinetics is not well understood for FSW process. For aluminum alloy, the material undergoes various thermal and mechanical histories that strongly influence the final microstructures through prevailing of preferably continuous dynamic recrystallization over a wide range of temperature and strain rate. The recrystallization mechanism plays a significant role on grain refinement and finally influences the weld joint strength. This process determines the microstructure and properties of welded joint and it is imperative to gain better understanding and control of recrystallization process in this circumstances. In the present work, an investigation is carried out on recrystallization mechanism as a function of temperature, strain and strain rate during FSW process. An analytical model for continuous dynamic recrystallization has been developed to predict average size of friction stir welded sample for different process variables.

Keywords- dynamic recrystallization, grain refinement, severe plastic deformation, aluminum alloy, friction stir welding

Unique Identification Number - IJEDR1801091
Page Number(s) - 525-533
Pubished in - Volume 6 | Issue 1 | March 2018
DOI (Digital Object Identifier) -   
Publisher - IJEDR (ISSN - 2321-9939)

  Haftu Hagazi Hadgu,   "Effect of physical variables in dynamic recrystallization during friction stir welding of aluminum alloy", International Journal of Engineering Development and Research (IJEDR), ISSN:2321-9939, Volume.6, Issue 1, pp.525-533, March 2018, Available at :http://www.ijedr.org/papers/IJEDR1801091.pdf