About this Abstract |
Meeting |
MS&T21: Materials Science & Technology
|
Symposium
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Additive Manufacturing: Advanced Characterization for Industrial Applications
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Presentation Title |
In-situ Characterization of Pore Formation Dynamics in Pulsed Wave Laser Powder Bed Fusion |
Author(s) |
Seyed Mohammad Hassan Hojjatzadeh, Qilin Guo, Niranjan D. Parab, Minglei Qu, Luis I. Escano, Kamel Fezzaa, Wes Everhart, Lianyi Chen |
On-Site Speaker (Planned) |
Seyed Mohammad Hassan Hojjatzadeh |
Abstract Scope |
Laser powder bed fusion (LPBF) is an additive manufacturing technology with the capability of printing complex metal parts directly from digital models. Between two available emission modes employed in LPBF printing systems, pulsed wave (PW) emission provides more control over the heat input compared to continuous wave (CW) emission. However, parts printed with pulsed wave LPBF (PW-LPBF) commonly contain pores, which degrades their mechanical properties. Here, we reveal pore formation mechanisms during PW-LPBF in real time by using in situ high-speed synchrotron x-ray imaging technique. We found the vapor depression collapse proceeds when the laser irradiation stops within one pulse, resulting in occasional pore formation during PW-LPBF. We also revealed that the rapid melt pool solidification during pulsed-wave laser melting resulted in cavity formation and subsequent formation of pore pattern in the melted track. The pore formation dynamics revealed in this study can provide guidance on developing pore elimination approaches. |