About this Abstract | 
  
   
    | Meeting | 
    2021 TMS Annual Meeting & Exhibition
       | 
  
   
    | Symposium 
       | 
    Additive Manufacturing of Metals: Applications of Solidification Fundamentals
       | 
  
   
    | Presentation Title | 
    In Situ Imaging of the Effect of Gas Flowrates on Directed Energy Deposition | 
  
   
    | Author(s) | 
    Lorna  Sinclair, Yunhui  Chen, Samuel J. Clark, Oliver  Hatt, Sebastian  Marussi, Saurabh  Shah, Robert C. Atwood, Martyn  Jones, Gavin   Baxter, Chu Lun Alex  Leung, Iain  Todd, Peter D. Lee | 
  
   
    | On-Site Speaker (Planned) | 
    Lorna  Sinclair | 
  
   
    | Abstract Scope | 
    
Directed Energy Deposition (DED) is a fabrication technique for rapid part production, coatings, and repair applications. However, careful selection of processing conditions is essential for obtaining the desired mechanical properties. Gas flowrates can affect the powder delivery, powder capture efficiency, and oxidation of a component. In this study, different carrier gas (powder delivery) and shielding gas (creating an inert environment around the laser) flowrates have been investigated. A unique DED process replicator has been used to observe laser deposition in situ via high-speed synchrotron radiography, revealing gas flowrate impacts on melt pool size and shape. An industrial DED machine (BeAM Magic 800) was used to build tracks under analogous processing conditions for comparison. The results showed that low gas flowrates led to thicker deposition layers and track oxidation, whereas high shield gas led to flatter, wider melt pools, and thinner deposition layers than intended.  | 
  
   
    | Proceedings Inclusion? | 
    Planned:  |