About this Abstract |
Meeting |
2022 TMS Annual Meeting & Exhibition
|
Symposium
|
Advances in Surface Engineering IV
|
Presentation Title |
Unraveling the Roles of Thickness, Crystallinity and Composition of Powder Passivation Layers during Cold Spraying of Aluminum Powder |
Author(s) |
Cameron Crook, Seyed Amirhossein Saeidi, Diran Apelian, Daniel Mumm, Lorenzo Valdevit |
On-Site Speaker (Planned) |
Cameron Crook |
Abstract Scope |
Cold spray of aluminum powders is heavily influenced by the native passivation layer which forms under ambient conditions. Under humid atmospheric conditions at room temperature, this passivation layer readily thickens, increasing the critical adhesion velocity while reducing bonding and deposition efficiency. For structural repair applications, bonding is critical; however, it is unclear whether passivation layer crystallinity, thickness, and composition or some combination thereof is principally responsible. Here we perform surface modification to grow Al powder passivation layers of varying crystallinity, thickness and composition. High resolution electron microscopy and single particle impact experiments directly correlate the passivation layer microstructure and critical adhesion. Further examination is performed using density functional theory calculations of the mechanical properties of alumina polymorphs including amorphous and hydrated systems and empirical shock relations. These results give credence to thickness and crystallinity being the main drivers of increases in critical adhesion velocity. |
Proceedings Inclusion? |
Planned: |
Keywords |
Powder Materials, Process Technology, Surface Modification and Coatings |