Enhancing the Mechanical and Metallurgical Behavior of Post-Processing on Friction Stir Processed AA8011 with NiTi-SMAs and Si ₃ N ₄ Surface Hybrid Composites 2020-28-0419

This limited research was extended to study the modification surface amendment of materials through Friction Stir Process (FSP) with nanoparticle addition followed by the post-processing method. In this paper, strengthened core and surface properties of AA8011 has been enhanced by adding nanoparticles such as Nitinol shape memory alloy (NiTi-SMAs) and silicon nitrate (Si₃N₄) through FSP followed by two different way of post-processing techniques like case hardening, case harden with shot peening. During FSP the use of NiTi-SMAs and Si₃N₄ as reinforcement interlocked the grains in hybrid nano composites of the processed zone. Also besides, post-processing promises a performance enhancement of core and surface hardness, ultimate tensile strength, impact strength and homogeneous distribution which was observed through scanning electron microscopic observations. The study has revealed that the case harden with shot peening FSP’ed hybrid composite surface has preferably higher performance than case hardening and non-post processed technique. The case harden with shot peening has a great impact on induced compressive residual stress with absents of crack closure. This technique also improves significantly the fatigue life of the material while loading. The strengthening phase was uniformly distributed in grain or grain boundary and also the hardened layer was evaluated using surface integrity with metallography study. On the whole, it was concluded that the coupled effect of reinforcement addition and case-harden with shot peening technique was the best choice in augmenting demanded industries for this FSP’ed hybrid composites.