3D Monte Carlo simulation of grain growth in friction stir welding

The 3D fluid model was used to simulate the friction stir welding process. Three-dimensional Monte Carlo model with nucleation in each MC step was then applied to simulate the grain growth. The validity of this model is verified by comparison with the experimental and numerical results. The influences of tool shoulder diameter and rotational speed are further studied. Equiaxed grains in the stirring zone are increased with the increase of the diameter and the rotation speed of the shoulder. The grain sizes tend to be more uniform from retreating side to advancing side when the rotational speed or shoulder diameter is increased.