A moving boundary formulation for recursive plastic heat release during friction stir welding

In this paper, a model for the growth of third region during friction stir welding is presented. The domain of interest is the heat and deformation affected zone under the tool shoulder. The model integrates a moving boundary framework for the growth of a stirring induced plastic flow region within the domain and formulates the heat generated by recursive plastic work as an enthalpy jump condition across the moving interface. From global energy balance considerations, the approach provides the means to estimate the time required to develop the stirring induced plastic flow region as a function of tool geometry (shoulder radius and pin radius).