Temperature, plastic strain and heat generation during the plunge stage of
the friction stir welding (FSW) of high-strength aluminium alloys 2024 T3 and
2024 T351 are considered in this work. The plunging of the tool into the
material is done at different rotating speeds. A three-dimensional finite
element (FE) model for thermomechanical simulation is developed. It is based
on arbitrary Lagrangian-Eulerian formulation, and Johnson-Cook material law
is used for modelling of material behaviour. From comparison of the numerical
results for alloys 2024 T3 and 2024 T351, it can be seen that the former has
more intensive heat generation from the plastic deformation, due to its
higher strength. Friction heat generation is only slightly different for the
two alloys. Therefore, temperatures in the working plate are higher in the
alloy 2024 T3 for the same parameters of the plunge stage. Equivalent plastic
strain is higher for 2024 T351 alloy, and the highest values are determined
under the tool shoulder and around the tool pin. For the alloy 2024 T3,
equivalent plastic strain is the highest in the influence zone of the tool
pin.