Friction stir additive manufacturing – An innovative tool to enhance mechanical and microstructural properties

•FSAM is the new class of metal additive manufacturing (MAM) technique utilized for improved microstructural and mechanical properties.•Very limited articles are available in open literature on the research outcomes of FSAM.•Present work highlights the detailed background of the FSAM and reported the findings and results reported by previous authors.•It also discussed the futuristic approach of FSAM and its application in various fields of engineering and medical. Friction stir additive manufacturing (FSAM) method is one of the growing techniques of additive manufacturing that utilizes the concept of solid state friction stir processing to develop multilayer components through layer by layer joining. The present work aims to highlight the working principle and the past research work carried out by the various authors that utilize FSAM as a fabrication process. Based on the available experimental data, the summary of additive based friction stir processes, type of machine for fabrication, materials, process parameters taken for the study is also discussed in detail. Mechanical properties such as grain refinement, microhardness variation, and tensile strength are also summarized, in comparison with their base materials. In addition, the current scenario and future scope of the FSAM process are also discussed in detail in terms of its utilization in various sectors of engineering along with estimated future trends.