Use of Additive Friction Stir in Mg Alloys (Powder and Solid)

Additive Friction Stir (AFS) is a novel solid-state thermo-mechanical process for deposition of metal or metal matrix composites (MMCs) used in a variety of applications across a wide spectrum of materials.  AFS allows use of solid, powder or combinations of powder to be used as “filler” material. Filler material is forced to flow through the hollow AFS tool and is then stirred into the substrate at a high deposition rate.  The process yields a metallurgical bond between added material and substrate with refined grain structure.  Because it is solid-state, unweldable materials may be used.  Due to its additive nature, AFS can be used for coating, repair, or additive manufacturing of similar or dissimilar materials.

In this presentation, use of AFS technology with magnesium alloys will be explored.  Example applications include the repair of damaged parts, fabrication of billets from powders, and near-net shape additively manufactured parts.  Microstructure, bond strength, material properties, and testing results will be reviewed.  Microstructural evolution of powder filler materials in process will be shown to demonstrate how AFS is capable of processing powders regardless of their shape and size.  Data for an additively manufactured part with higher strength in the short transverse than the parent base material will be provided.

Process data for projects for US ARMY ARDEC, ARL, and commercial entities will be shared and will include E675 Magnesium, atomized Elektron MAP21 fine powder, AMX602 coarse powder produced by spinning water atomization process (SWAP), and both solid and powder WE43.