Title: Strong morphological and crystallographic texture and resulting yield strength anisotropy in Selective Laser Melted tantalum
Authors: Thijs, Lore ×
Montero Sistiaga, Maria
Wauthlé, Ruben
Xie, Qingge
Kruth, Jean-Pierre
Van Humbeeck, Jan #
Issue Date: Jul-2013
Publisher: Elsevier Science
Series Title: Acta Materialia vol:61 issue:12 pages:4657-4668
Article number: 10613
Abstract: Selective Laser Melting (SLM) makes use of a high energy density laser beam to melt successive layers of metallic powders in order to create functional parts. The energy density of the laser is high enough to melt refractory metals like Ta and produce mechanically sound parts. Furthermore, the localized heat input causes a strong directional cooling and solidification. Epitaxial growth due to partial remelting of the previous layer, competitive growth mechanism and a specific global direction of heat flow during SLM of Ta result in the formation of long columnar grains with a <111> preferential crystal orientation along the building direction. The microstructure was visualized using both optical and scanning electron microscopy equipped with electron backscattered diffraction and the global crystallographic texture was measured using X-ray diffraction. The thermal profile around the melt pool was modeled using a pragmatic model for SLM. Furthermore, rotation of the scanning direction between different layers was seen to promote the competitive growth. As a result, the texture strength increased to as large as 4.7 for rotating the scanning direction 90° every layer. By comparison of the yield strength measured by compression tests in different orientations and the averaged Taylor factor calculated using the visco-plastic self-consistent (VPSC) model, it was found that both the morphological and crystallographic texture observed in SLM Ta contribute to yield strength anisotropy.
ISSN: 1359-6454
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Production Engineering, Machine Design and Automation (PMA) Section
Structural Composites and Alloys, Integrity and Nondestructive Testing
Surface and Interface Engineered Materials
× corresponding author
# (joint) last author

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