Modeling and Simulations of Multi-dimensional Thermal Behaviours of Plates during Friction Stir Additive Manufacturing

Friction-stir additive manufacturing is a type of solid-state additive manufacturing process that involves intense shear deformation of material during the material joining process. The increasing application of the novel technology requires proper understanding of the inherent thermal process. The analysis of the transient thermal behavior in three dimensions of the welded plates in friction-stir additive manufacturing is studied using Laplace transforms method is presented. It was established from the results that the material reduces in temperature during the simulation process as the distance of the point moving heat source increases from the centerline. Also, the time needed to attain the highest temperature increases with increasing distance between the point moving heat source and the centerline. In addition, the heating and cooling rates decrease while the distance between the point moving heat source and the centerline increases. The peak temperature is approximately 1200oC but this depends on the welding conditions, heat generation the materials, etc. The variation of shoulder heat generation rate with welding rotational speed at different welding velocities of 100-200 mm/min depicts that increasing the tool rotational speed at constant weld speed increases the heat input, whereas the heat input decreases with an increase in the weld speed at constant tool rotational speed. It was also established that the fractional heat generation rate is between 80 to 90% heat is generated at the tool shoulder and the remaining amount at other tool surfaces. However, this depends on the welding conditions. Finally, the temperature profile typical features can be observed from the obtained results at varying monitoring points, and they provide a better analysis of the prevailing factors in the heat flow model for a point moving heat source. Hence, the model and analytical solution provide the benchmark for obtaining temperature profiles for point moving heat source during the additive manufacturing process.