| Abstract Scope |
Additive friction stir deposition (AFSD) is a large scale, solid-state additive manufacturing technique that lends itself to many naval applications. With further research, an AFSD machine could be used shipboard to build custom parts with desirable properties, coat large surfaces for corrosion prevention, or repair in-service components. As opposed to melting-based metal additive manufacturing, AFSD uses friction from tool rotation to deform and deposit the feed material. That promotes strong interface bonding, no detectable porosity, and isotropic, fine grained microstructures which all lead to good mechanical properties. Based on dissimilar material cladding and tracer experiments, physical insights into the material flow at the interface and within the deposition zone have been obtained, wherein X-ray computed tomography and electron backscatter diffraction reveal the 3-D morphology of the deposited material and the microstructure evolution. The asymmetric bowl-shaped interface is characterized by interlocking features and significant macroscopic material mixing. |