Effect of vibration on machining and mechanical properties of AZ91 alloy during FSP: modeling and experiments

The objective of the research is to determine the effect of friction stir processing (FSP) parameters and vibration on the machining behavior of AZ91 alloy. The article displays the state of the art of AZ91 alloy machinability including chip formation, chip morphology, and cutting forces. In this method, the vibration was applied to the process line through the fixture under the workpiece during the FSP. The three-dimensional finite element (FE) modeling was applied for simulating the small-hole drilling process of AZ91 alloy. The large deformation of work and the chip formation in drilling process is realized by incorporating Johnson-Cook material constitutive model and material failure criterion. It was concluded that the microstructure from 150 (mu m) for base metal was modified to 28 (mu m) and 16 (mu m) for FSP and FSVP samples, respectively. It has been indicated that mechanical properties increase as vibration applied during the FSP. The vibration improves adiabatic shearing and thus leads to more discontinuous chips. To enhance the mechanical and machining properties of processed zone the friction stir vibration process as an "easy to apply" FSP method is recommended for different industries.