|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Additive Manufacturing: Advanced Characterization with Synchrotron, Neutron, and In Situ Laboratory-scale Techniques II
||Keyhole Melting Regimes and Porosity Formation during Laser Powder Bed Fusion Additive Manufacturing
||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)
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.
||Additive Manufacturing, Aluminum, Other