Abstract
The nucleation and growth of chimney pores during powder-bed electron-beam additive manufacturing is investigated using in situ infrared thermography and micro-computed tomography. The chimney pores are found to nucleate heterogeneously at dimples on the side surfaces of additively manufactured components, and to grow through a molten-film rupture process. Further, these nucleation and growth processes are found to be strongly influenced by the beam diameter. Several strategies for suppressing the formation of chimney pores are discussed in light of these results.
Original language | English |
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Pages (from-to) | 3429-3435 |
Number of pages | 7 |
Journal | Journal of Materials Science |
Volume | 52 |
Issue number | 6 |
DOIs | |
State | Published - Mar 1 2017 |
Funding
This research was sponsored in part by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Advanced Manufacturing Office, under contract DE-AC05-00OR22725 with UT Battelle, LLC. The authors acknowledge assistance from Mr. Larry Lowe of the Oak Ridge National Laboratory and Ben George of the Air Force for performing the builds, and Dr. Johan Backlund of the Arcam AB Corp. for providing the beam diameters given in Table . ZCC is thankful to Mr. Michael Gibson of the Massachusetts Institute of Technology for a thought-provoking discussion on chimney pore growth.