Friction stir processing strategies to develop a surface composite layer on AA6061-T6

ABSTRACTFriction stir processing (FSP) has been used to produce metal matrix composites by incorporating reinforcement particles in an AA6061-T6 matrix. Two types of particles (Al2O3 and SiC) were tested. Powder was placed into a mechanized square section groove on a plate surface and then sealed before FSP. This study investigates the effect of several strategies for reinforcement (number and direction of FSP passes) on the wear resistance behavior of friction stir-processed Al-SiC/Al2O3 composites. The distribution and size of the particles in the friction stir-processed zone were studied by optical and scanning electron microscopy. Ball-on-disk test was performed on both base material and surface metal matrix composites (SMMCs), and both friction coefficient and specific wear rate (SWR) were correlated with particle distribution and metallurgical effects on the metallic matrix. For all strategies and for both types of reinforcing particles used in this study, the friction coefficient decreases with res...