In-Situ Characterization of Pore Formation Dynamics in Pulsed Wave Laser Powder Bed Fusion
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 compare...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-05-01
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| Series: | Materials |
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| Online Access: | https://www.mdpi.com/1996-1944/14/11/2936 |
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| author | S. Mohammad H. Hojjatzadeh Qilin Guo Niranjan D. Parab Minglei Qu Luis I. Escano Kamel Fezzaa Wes Everhart Tao Sun Lianyi Chen |
| author_facet | S. Mohammad H. Hojjatzadeh Qilin Guo Niranjan D. Parab Minglei Qu Luis I. Escano Kamel Fezzaa Wes Everhart Tao Sun Lianyi Chen |
| author_sort | S. Mohammad H. Hojjatzadeh |
| collection | DOAJ |
| description | 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, which is highly beneficial for printing parts with intricate features. However, parts printed with pulsed wave LPBF (PW-LPBF) commonly contain pores, which degrade their mechanical properties. In this study, we reveal pore formation mechanisms during PW-LPBF in real time by using an in-situ high-speed synchrotron x-ray imaging technique. We found that 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 melt ejection and rapid melt pool solidification during pulsed-wave laser melting resulted in cavity formation and subsequent formation of a pore pattern in the melted track. The pore formation dynamics revealed here may provide guidance on developing pore elimination approaches. |
| first_indexed | 2024-03-10T10:54:36Z |
| format | Article |
| id | doaj.art-5fc20ad9e1534f2a95e1e8750c8e09b2 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-10T10:54:36Z |
| publishDate | 2021-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-5fc20ad9e1534f2a95e1e8750c8e09b22023-11-21T21:59:25ZengMDPI AGMaterials1996-19442021-05-011411293610.3390/ma14112936In-Situ Characterization of Pore Formation Dynamics in Pulsed Wave Laser Powder Bed FusionS. Mohammad H. Hojjatzadeh0Qilin Guo1Niranjan D. Parab2Minglei Qu3Luis I. Escano4Kamel Fezzaa5Wes Everhart6Tao Sun7Lianyi Chen8Department of Mechanical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USADepartment of Mechanical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USAX-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USADepartment of Mechanical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USADepartment of Mechanical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USAX-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USADepartment of Energy’s Kansas City National Security Campus Managed by Honeywell FM&T, Kansas City, MO 64147, USADepartment of Materials Science and Engineering, University of Virginia, Charlottesville, VA 22904, USADepartment of Mechanical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USALaser 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, which is highly beneficial for printing parts with intricate features. However, parts printed with pulsed wave LPBF (PW-LPBF) commonly contain pores, which degrade their mechanical properties. In this study, we reveal pore formation mechanisms during PW-LPBF in real time by using an in-situ high-speed synchrotron x-ray imaging technique. We found that 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 melt ejection and rapid melt pool solidification during pulsed-wave laser melting resulted in cavity formation and subsequent formation of a pore pattern in the melted track. The pore formation dynamics revealed here may provide guidance on developing pore elimination approaches.https://www.mdpi.com/1996-1944/14/11/2936laser powder bed fusionadditive manufacturingporepulsed emissionX-ray imaging |
| spellingShingle | S. Mohammad H. Hojjatzadeh Qilin Guo Niranjan D. Parab Minglei Qu Luis I. Escano Kamel Fezzaa Wes Everhart Tao Sun Lianyi Chen In-Situ Characterization of Pore Formation Dynamics in Pulsed Wave Laser Powder Bed Fusion Materials laser powder bed fusion additive manufacturing pore pulsed emission X-ray imaging |
| title | In-Situ Characterization of Pore Formation Dynamics in Pulsed Wave Laser Powder Bed Fusion |
| title_full | In-Situ Characterization of Pore Formation Dynamics in Pulsed Wave Laser Powder Bed Fusion |
| title_fullStr | In-Situ Characterization of Pore Formation Dynamics in Pulsed Wave Laser Powder Bed Fusion |
| title_full_unstemmed | In-Situ Characterization of Pore Formation Dynamics in Pulsed Wave Laser Powder Bed Fusion |
| title_short | In-Situ Characterization of Pore Formation Dynamics in Pulsed Wave Laser Powder Bed Fusion |
| title_sort | in situ characterization of pore formation dynamics in pulsed wave laser powder bed fusion |
| topic | laser powder bed fusion additive manufacturing pore pulsed emission X-ray imaging |
| url | https://www.mdpi.com/1996-1944/14/11/2936 |
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