Investigation on tool wear in friction stir welding of SiCp/Al composites

The hard particles in particle-reinforced aluminum matrix composites significantly increases tool wear during friction stir welding (FSW), resulting in the shortage of tool life. In this study, SiCp/Al composites are used as the research object, and the tool wear experiment in friction stir welding is carried out by using high-speed steel pin and high-speed steel + AlCrN coated pin. A new method for calculating tool wear based on hydrodynamic pressure is proposed, and the tool pin wear prediction model is established and verified by experiments. The results show that the wear rate of AlCrN coated pin is very low at the beginning, indicating that AlCrN coating can extend the tool life to a certain extent. However, the wear rate of the tool will increase significantly after the coating is worn away. Through the analysis of the surface wear morphology of the pin, it is found that the main mechanisms of tool wear in the friction stir welding of SiCp/Al composites are the micro ploughing and micro cutting of SiC particles.