Physical and Numerical Simulations of the Microstructure Evolution in AA6082 during Friction Stir Processing by Means of Hot Torsion and FEM

Abstract

A reproduction of the conditions occurring during friction stir processing, where a fine grained structure according to the process parameters rpm, transverse speed and pressure develops is the main focus in the present work. To physically simulate such a friction stir process, hot torsion tests at constant temperatures were carried out in a Gleeble ® 3800 machine at different strains and strain rates. The specimens were immediately water quenched after hot deformation to avoid any static recrystallization. The microstructure was investigated to characterize the grain size evolution and misorientation as a function of the local strain, strain rate and temperature. Dynamic recovery was observed followed by continuous dynamic recrystallization at large deformations. By means of DEFORMTM3D the occurring strain, strain rate and temperature distributions, which are decisive for the observed microstructure evolution, were evaluated.

The microstructural evolution of friction stir welded AA6082-T6 aluminum alloy during cyclic deformation

“…It has been revealed that in the friction stir processing (FSP) of aluminium alloys, the microstructure in the NG is deformed to a very large extent and grain rotation at high cyclic strains takes place [41]. The present experimental results reveal that the activity of grain boundary cracking as such suggests that some more grain rotation did occur.…”