Effect of Annealing on Anisotropic Tensile Properties of Al–12%Si Alloy Fabricated by Laser Powder Bed Fusion
1
Department of Materials Process Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
2
Aichi Center for Industry and Science Technology, 1267-1 Akiai, Yakusa-cho, Toyota 470-0356, Japan
*
Author to whom correspondence should be addressed.
Crystals 2020, 10(11), 1007; https://doi.org/10.3390/cryst10111007
Received: 30 September 2020 / Revised: 3 November 2020 / Accepted: 4 November 2020 / Published: 5 November 2020
(This article belongs to the Special Issue Additive Manufacturing: Materials, Processing, Characterization and Applications)
In this study, we systematically investigated microstructures and tensile properties of an Al–12mass%Si alloy additive-manufactured by laser powder bed fusion (LPBF) process and subsequently annealed at various temperatures. Microstructure of the as-fabricated sample was characterized by a number of melt pools consisting of α-Al phases surrounded by Si eutectic phases. Fine Si precipitates were observed in the α-Al phase in the sample annealed at 200 °C. The eutectic Si phase appears to agglutinate, resulting in a coarsened Si phase formed at high temperatures above 300 °C. The initial cellular microstructure completely disappears and a number of coarsened Si phases and plate-shaped intermetallic phases (β-AlFeSi) were formed in the sample annealed at 530 °C. However, the grain morphology of the α-Al matrix slightly changed after the annealing at high temperatures. The as-fabricated specimen showed a high strength above 400 MPa and a low ductility of below 10% in total elongation. The tensile ductility varied depending on the tensile direction. The annealed specimens exhibited a lower tensile strength and larger elongation, whereas the direction dependence of the tensile properties was less pronounced in the specimens annealed at higher temperatures. The anisotropic tensile ductility can be rationalized by preferential fractures occurred around melt pool boundaries.
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Keywords:
additive manufacturing; aluminum alloy; annealing; microstructural development; direction dependence of tensile property
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MDPI and ACS Style
Liu, M.; Wada, T.; Suzuki, A.; Takata, N.; Kobashi, M.; Kato, M. Effect of Annealing on Anisotropic Tensile Properties of Al–12%Si Alloy Fabricated by Laser Powder Bed Fusion. Crystals 2020, 10, 1007. https://doi.org/10.3390/cryst10111007
AMA Style
Liu M, Wada T, Suzuki A, Takata N, Kobashi M, Kato M. Effect of Annealing on Anisotropic Tensile Properties of Al–12%Si Alloy Fabricated by Laser Powder Bed Fusion. Crystals. 2020; 10(11):1007. https://doi.org/10.3390/cryst10111007
Chicago/Turabian StyleLiu, Mulin; Wada, Takafumi; Suzuki, Asuka; Takata, Naoki; Kobashi, Makoto; Kato, Masaki. 2020. "Effect of Annealing on Anisotropic Tensile Properties of Al–12%Si Alloy Fabricated by Laser Powder Bed Fusion" Crystals 10, no. 11: 1007. https://doi.org/10.3390/cryst10111007
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