Influence of Tool Tilt Angle on the Formation of Friction Stir Processing Zone in Cast Magnesium Alloy ZK60/SiCp Surface Composites

Cast ZK60 magnesium alloy has significant beneficial properties including high strength-to-weight ratio. Poor surface properties such as low friction and wear resistance restrict the use of this alloy in structural applications. Therefore, it is very much essential to adopt surface engineering to enhance this alloy’s surface properties. Friction stir processing is one of the potential thermo-mechanical processing techniques that alters the microstructural and tribological properties of the material. In the present study, ZK60/SiCp was fabricated by means of FSP. Tool tilt angle is a critical process parameter which influences the material flow, and particle breakup and distribution in the processed zone. In this work, an attempt has been made to understand the effects of tool tilt angle (ranges 0°–4°) on the grain refinement of matrix and the distribution of SiC particles. It is shown that the FSPed materials zone produced using the tilt angle 2° exhibited higher hardness (125 Hv); this was attributed to the optimization of heat generation, material flow, grain boundary strengthening, and homogeneous particle distribution.