INTEGRATED MODELLING OF TOOL WEAR AND MICROSTRUCTURAL EVOLUTION INTERNAL RELATIONS IN FRICTION STIR WELDING WITH WORN PIN PROFILES

摘要

An adaptive remeshing model was coupled with the Archard equation to calculate the tool wear in friction stir welding (FSW). The Monte Carlo method was used to simulate recrystallization in FSW with worn tools. In addition, experiments were used to validate the predicted temperatures and microstructures. As indicated by the results, appropriate tool wear can lead to self-optimization of the tool in FSW. This wear mechanism is controlled by the change in the average strain rate during the FSW process. The average strain rate first increases and then decreases with tool wear, which is the key factor when determining the final grains. An appropriate amount of tool wear can lead to smaller grains in the stirring zone of FSW whereas excess tool wear can lead to larger grains.