Laser powder-bed fusion additive manufacturing [electronic resource] : Physics of complex melt flow and formation mechanisms of pores, spatter, and denudation zones

Published:: Washington, D.C. : United States. Dept. of Energy, 2016.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
Physical Description:: pages 36-45 : digital, PDF file
Additional Creators:: Lawrence Berkeley National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information

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Summary:

Our study demonstrates the significant effect of the recoil pressure and Marangoni convection in laser powder bed fusion (L-PBF) of 316L stainless steel. A three-dimensional high fidelity powder-scale model reveals how the strong dynamical melt flow generates pore defects, material spattering (sparking), and denudation zones. The melt track is divided into three sections: a topological depression, a transition and a tail region, each being the location of specific physical effects. The inclusion of laser ray-tracing energy deposition in the powder-scale model improves over traditional volumetric energy deposition. It enables partial particle melting, which impacts pore defects in the denudation zone. Different pore formation mechanisms are observed at the edge of a scan track, at the melt pool bottom (during collapse of the pool depression), and at the end of the melt track (during laser power ramp down). Finally, we discuss remedies to these undesirable pores are discussed. The results are validated against the experiments and the sensitivity to laser absorptivity.

Report Numbers:

E 1.99:llnl-jrnl--676495
llnl-jrnl--676495

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Note:

Published through SciTech Connect.
02/23/2016.
"llnl-jrnl--676495"
Acta Materialia 108 C ISSN 1359-6454 AM
Saad A. Khairallah; Andrew T. Anderson; Alexander Rubenchik; Wayne E. King.

Funding Information:

AC52-07NA27344

View MARC record | catkey: 23503947