Modeling of Friction Stir Processing using 3D CFD analysis

Friction Stir Processing (FSP) has emerged as an effective tool for enhancing sheet metal properties through microstructural modification of processed materials. Despite the large number of studies, most of the work that has been done in the FSP field focuses primarily on experimental work. Only limited modeling attempts on temperature distribution and strain rate analysis have been conducted. In this work, a three dimensional Computational Fluid Dynamics (CFD) model was developed to simulate FSP using the STAR CCM+ CFD commercial software. User-defined subroutines were developed and implemented to investigate the effects of process parameters on temperature, strain rate, flow stress and material velocity fields in, and around, the processed nugget. In addition, a correlation between process parameters and the Zener-Holloman parameter was developed to predict the grain size distribution in the processed zone. Different stirring conditions were incorporated in this study to investigate their effects on material flow and microstructural modification. The modeling results were compared with the available experimental data and showed good agreement.