Microstructural Characterization and Microhardness Investigations on Friction Stir Additive Manufactured Commercially Pure Aluminium Alloy

Friction stir additive manufacturing (FAM) is the advanced technology used in layer-by-layer addition and processing of the materials. In this study, the effect of process parameters on the hardness of FAM Al1100 aluminium plates was investigated. Tool rotating and travel speeds were the process parameters varied in two levels. The metallographic and microhardness FAM samples were evaluated. The results revealed that low rotational speed and travel speed combinations show higher hardness due to survival of intermetallic particles and formation of equiaxed and refined grains. However, in case of higher tool rotational and travel speed combinations, formation of elongated grains and dissolution of secondary phase particles into the matrix leads to the reduction in hardness.