This paper deals with analysis and comparison of the equivalent plastic
strain and temperature fields in the aluminium alloy 2024 T3 welded joint,
with macro/microstructure appearance and hardness profile. In the alloys
hardened by heat treatment, grain size and particle size of the precipitate
are functions of equivalent plastic strain, strain rate and temperature. By
analyzing the equivalent plastic strain fields and temperature fields it is
possible, to some extent, to capture the effect of welding parameters and
thermo-mechanical conditions on grain structure, and therefore hardness and
strength in the welded joint. A coupled thermo-mechanical model is applied
to study the material behaviour during the linear welding stage of friction
stir welding (FSW). Three-dimensional finite element (FE) model has been
created in ABAQUS/Explicit software using the Johnson-Cook material law. The
values of thermo-mechanical quantities during the welding stage are obtained
from the numerical model and shown as distributions across the joint. The
obtained values of these quantities are related to the microstructure of the
joint zones and hardness distribution, and this relation is discussed.