Novel Tribo-Corrosion Mechanisms of Friction Stir Processed Steel Manufactured by High-Pressure Deposition Additive Manufacturing Process

The application of high-pressure deposition (HPD) technologies has greatly reduced the
dilapidation of mechanical components used in moving mechanical assemblies (MMAs). Due to
the mechanical and metallurgical bonding of rapidly accelerated particles, robust and reliable
coatings can be rapidly applied in a plethora of applications. However, due to the non-uniform
deformation of the accelerated particles, defects in the form of voids are quite common. As such,
their performance and collective lifespans are limited, especially when exposed to simultaneous
chemical-abrasion environments. This creates an ever-increasing need to understand their wear corrosion mechanisms and how their structure-property relationships can be improved to overcome
these limitations. In this work, we study the novel tribo-corrosion mechanisms of HPD coatings
and understand how their change in interparticle bonding mechanics can be optimized to improve
their tribo-corrosion performance. By correlating the microstructural, atomic, and mechanical
properties of these coatings subjected to friction stir processing (FSP), it was found that the
combination of surface densification and hardness greatly reduced its wear loss. As such, it was
determined that FSP is indeed a viable technique for post-process modification. The critical and
novel changes in tribo-corrosion mechanisms were also identified and elucidated.