| About this Abstract | 
   
    | Meeting | 2022 TMS Annual Meeting & Exhibition | 
   
    | Symposium | Additive Manufacturing: Advanced Characterization with Synchrotron, Neutron, and In Situ Laboratory-scale Techniques II | 
   
    | Presentation Title | Keyhole Melting Regimes and Porosity Formation during Laser Powder Bed Fusion Additive Manufacturing | 
   
    | Author(s) | Yuze  Huang, Tristan G.  Fleming, Chu Lun Alex   Leung, Samuel J.   Clark, Sebastian   Marussi, Kamel   Fezzaa, Jakumeit  Jürgen, Jeyan  Thiyagalingam, Peter D.  Lee | 
   
    | On-Site Speaker (Planned) | Yuze  Huang | 
   
    | Abstract Scope | Keyhole porosity is a major concern in laser powder-bed fusion, degrading the fatigue life of fabricated components. However, the keyhole fluctuation and porosity formation mechanism have not been fully understood. We have used synchrotron X-ray imaging to reveal keyhole fluctuation and collapse behaviours, unveiled their underlying mechanisms using quantitative image analysis. It was found that (i) the onset of keyhole porosity starts from a transition keyhole regime, created by high laser power-velocity conditions, showing the fastest radial fluctuations with frequency ~10 kHz; (ii) unlike the keyhole bottom collapse in the unstable keyhole regime, keyholes tend to collapse at rear-wall zone in the transition regime; (iii) The keyhole regimes are found to be well defined by the keyhole front-wall angle, which collapses to a single function of the scaling enthalpy.These findings provide vital guidance for pore suppression via real-time control of keyhole dynamics in LPBF and other high-beam-energy processing techniques. | 
   
    | Proceedings Inclusion? | Planned: | 
 
    | Keywords | Additive Manufacturing, Aluminum, Other |