General Introduction and Need of Friction Based Additive Manufacturing Techniques
Currently, all the major commercial metal additive manufacturing (MAM) techniques rely on liquid-phase processing. The liquid- to solid-phase transformation in these techniques results in microstructural issues and defects, which result in inferior properties of the fabricated build. In addition, these processes are comparatively less suitable for MAM of nonferrous alloys, which necessitates the requirement of solid-state processing techniques. Solid-state MAM processes like sheet lamination, binders, and so on are utilized to reduce these solidification-related issues. However, these processes suffer from inhomogeneous microstructures and inferior mechanical properties as compared to base materials. Friction-based solid-state additive manufacturing techniques (FATs) are better suited for such applications. This is because friction-based processes work on temperatures below the melting point of material, and, due to severe plastic deformation and dynamic recrystallization, these techniques produce superior properties in additively manufactured parts as compared to base materials. The following text appreciates the need and importance of FATs and also provides details on how the book chapters are organized.