Metallurgically Bonded Metal Coatings on Solid and Foam Metals

Metal coatings offer increased wear and corrosion resistance for parts, and can be used in light weighting programs to reduce part weight without compromising performance.  However, particularly in extreme environments, coatings often crack and delaminate due to poor bonding.  Many coating processes require melting the coating material, which results in poor mechanical properties in addition to poor bonding. 

In this study, Additive Friction Stir (AFS), a solid-state process, was used to coat substrates. AFS coatings achieve a metallurgical bond and because no melting is involved, AFS coatings exhibit superior mechanical properties.  AFS-deposited metal coatings show no porosity with refined equiax grains.  Coatings of nickel based super alloys on steel plate and aluminum on aluminum foam will be reviewed in detail including evaluation of interface, detailed microstructure, hardness, and tensile properties.