Effect of nanoscale cellular structure on the mechanical properties of Inconel 718 with unique hierarchical structure fabricated by laser powder bed fusion

Cho, Ken; Yamashita, Kippei; Kakutani, Shinnosuke; Saito, Takuma; Sasaki, Taisuke; Sawaizumi, Katsuhiko; Okugawa, Masayuki; Koizumi, Yuichiro; Mayama, Tsuyoshi; Kikukawa, Taichi; Gokcekaya, Ozkan; Ishimoto, Takuya; Kimizuka, Hajime; Gong, Wu; Kawasaki, Takuro; Harjo, Stefanus; Nakano, Takayoshi; Yasuda, Hiroyuki Y.

doi:https://doi.org/10.1016/j.actamat.2025.121696

Effect of nanoscale cellular structure on the mechanical properties of Inconel 718 with unique hierarchical structure fabricated by laser powder bed fusion

Cho, Ken; Yamashita, Kippei; Kakutani, Shinnosuke et al.

Acta Materialia, 2025, 303, 121696

Number of Access:158（2026-02-06 00:35 Counts）

Identifier to cite or link to this item: https://hdl.handle.net/11094/103524

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Title	Effect of nanoscale cellular structure on the mechanical properties of Inconel 718 with unique hierarchical structure fabricated by laser powder bed fusion
Creator	NRID 1000000633661 1000000633661 ORCID 0009-0008-4612-6393 0009-0008-4612-6393 researchmap permalink choken choken Scopus Author ID 55535308400 55535308400 CreatorName Cho, Ken
	CreatorName Yamashita, Kippei
	CreatorName Kakutani, Shinnosuke
	CreatorName Saito, Takuma
	NRID 1000030615993 1000030615993 CreatorName Sasaki, Taisuke
	CreatorName Sawaizumi, Katsuhiko
	NRID 1000070847160 1000070847160 ORCID 0000-0002-6844-6856 0000-0002-6844-6856 researchmap permalink masayuki.okugawa masayuki.okugawa Scopus Author ID 57202824128 57202824128 CreatorName Okugawa, Masayuki
	NRID 1000010322174 1000010322174 ORCID 0000-0001-7061-7135 0000-0001-7061-7135 researchmap permalink YuichiroKoizumi YuichiroKoizumi Scopus Author ID 57202772340 57202772340 CreatorName Koizumi, Yuichiro
	NRID 1000040333629 1000040333629 CreatorName Mayama, Tsuyoshi
	CreatorName Kikukawa, Taichi
	NRID 1000050988160 1000050988160 ORCID 0000-0002-9258-858X 0000-0002-9258-858X Scopus Author ID 37051975500 37051975500 CreatorName Gokcekaya, Ozkan
	NRID 1000050508835 1000050508835 ORCID 0000-0003-0081-0591 0000-0003-0081-0591 researchmap permalink i_taku i_taku Scopus Author ID 35310484700 35310484700 CreatorName Ishimoto, Takuya
	NRID 1000060467511 1000060467511 CreatorName Kimizuka, Hajime
	NRID 1000030780770 1000030780770 CreatorName Gong, Wu
	NRID 1000020626361 1000020626361 CreatorName Kawasaki, Takuro
	NRID 1000040391263 1000040391263 CreatorName Harjo, Stefanus
	NRID 1000030243182 1000030243182 ORCID 0000-0001-8052-1698 0000-0001-8052-1698 researchmap permalink read0013987 read0013987 Scopus Author ID 7403896013 7403896013 CreatorName Nakano, Takayoshi
	NRID 1000060294021 1000060294021 ORCID 0000-0002-7077-0655 0000-0002-7077-0655 researchmap permalink read0051691 read0051691 Scopus Author ID 47861549600 47861549600 CreatorName Yasuda, Hiroyuki Y.
Subject	Additive manufacturing
	Cellular structure
	Crystallographic texture
	Neutron diffraction
	Nickel superalloys
	Strengthening mechanism
Description	Cho K., Yamashita K., Kakutani S., et al. Effect of nanoscale cellular structure on the mechanical properties of Inconel 718 with unique hierarchical structure fabricated by laser powder bed fusion. Acta Materialia 303, 121696 (2026); https://doi.org/10.1016/j.actamat.2025.121696.
Abstract	The deformation behavior and strengthening mechanism of Inconel 718 with a hierarchical structure composed of microscale crystallographic lamellar microstructure (CLM) and nanoscale cellular structure, fabricated by laser powder bed fusion, were clarified via nanoscale microstructural and in-situ neutron diffraction analyses. The CLM is a layered structure parallel to the building direction (BD) and consists of relatively wide main and narrow sub-layers with 〈110〉 and 〈100〉 orientations, respectively, with respect to BD. This is the first study to demonstrate that the yield stress of the alloys depends strongly on deformation stresses of the sub-layers, even though Schmid factors of the primary slip system for both layers are the same. The sub-layer continues to deform elastically even beyond the micro-yield point of the main layer, which results in the macroscopic strengthening at an early stage of deformation. On the other hand, the cellular structure is formed in both layers, associated with a dendritic cell growth along 〈100〉 direction, Nb segregation between the cells and an accumulation of dislocations to decrease a residual stress. The cell boundaries with numerous dislocations and Nb segregation act as a strong barrier to dislocation motion resulting in a stress increase through the Hall-Petch law, even though they are low-angle grain boundaries. The spacing and morphology of the cell boundary depend strongly on fabrication conditions. The optimized cellular structure provides significant strengthening comparable to or greater than that caused by large-angle grain boundaries, thereby increasing the macroscopic strength of the alloys through hardening of the sub-layer.
Publisher	Acta Materialia Inc
Source Title	Acta Materialia
Volume (Issue)	303
Page	121696
Date of Issued	2025-11-13
Language	English
Handle URL	https://hdl.handle.net/11094/103524
PISSN	13596454
Relation.isIdenticalTo	DOI (Publisher Version) https://doi.org/10.1016/j.actamat.2025.121696
Access Rights	open access
CopyRight	This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
oaire:version	Version of Record
Category	学術雑誌論文 Journal Article

Resource Type	journal article
Local Type	Journal Article
DCMI Type	Text
DCTERMS.bibliographicCitation	Acta Materialia. 2025, 303, p. 121696
DC.title	Effect of nanoscale cellular structure on the mechanical properties of Inconel 718 with unique hierarchical structure fabricated by laser powder bed fusion
DC.creator	Cho, Ken
	Yamashita, Kippei
	Kakutani, Shinnosuke
	Saito, Takuma
	Sasaki, Taisuke
	Sawaizumi, Katsuhiko
	Okugawa, Masayuki
	Koizumi, Yuichiro
	Mayama, Tsuyoshi
	Kikukawa, Taichi
	Gokcekaya, Ozkan
	Ishimoto, Takuya
	Kimizuka, Hajime
	Gong, Wu
	Kawasaki, Takuro
	Harjo, Stefanus
	Nakano, Takayoshi
	Yasuda, Hiroyuki Y.
DC.publisher	Acta Materialia Inc
DC.language' scheme='DCTERMS.RFC1766	English
DC.type' scheme='DCTERMS.DCMIType	Text
DCTERMS.issued' scheme='DCTERMS.W3CDTF	2025-11-13
DC.identifier	https://doi.org/10.1016/j.actamat.2025.121696
DC.subject	Additive manufacturing
	Cellular structure
	Crystallographic texture
	Neutron diffraction
	Nickel superalloys
	Strengthening mechanism
DC.description	Cho K., Yamashita K., Kakutani S., et al. Effect of nanoscale cellular structure on the mechanical properties of Inconel 718 with unique hierarchical structure fabricated by laser powder bed fusion. Acta Materialia 303, 121696 (2026); https://doi.org/10.1016/j.actamat.2025.121696.
DCTERMS.abstract	The deformation behavior and strengthening mechanism of Inconel 718 with a hierarchical structure composed of microscale crystallographic lamellar microstructure (CLM) and nanoscale cellular structure, fabricated by laser powder bed fusion, were clarified via nanoscale microstructural and in-situ neutron diffraction analyses. The CLM is a layered structure parallel to the building direction (BD) and consists of relatively wide main and narrow sub-layers with 〈110〉 and 〈100〉 orientations, respectively, with respect to BD. This is the first study to demonstrate that the yield stress of the alloys depends strongly on deformation stresses of the sub-layers, even though Schmid factors of the primary slip system for both layers are the same. The sub-layer continues to deform elastically even beyond the micro-yield point of the main layer, which results in the macroscopic strengthening at an early stage of deformation. On the other hand, the cellular structure is formed in both layers, associated with a dendritic cell growth along 〈100〉 direction, Nb segregation between the cells and an accumulation of dislocations to decrease a residual stress. The cell boundaries with numerous dislocations and Nb segregation act as a strong barrier to dislocation motion resulting in a stress increase through the Hall-Petch law, even though they are low-angle grain boundaries. The spacing and morphology of the cell boundary depend strongly on fabrication conditions. The optimized cellular structure provides significant strengthening comparable to or greater than that caused by large-angle grain boundaries, thereby increasing the macroscopic strength of the alloys through hardening of the sub-layer.
DC.rights	This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
DC.format	103524
citation_title	Effect of nanoscale cellular structure on the mechanical properties of Inconel 718 with unique hierarchical structure fabricated by laser powder bed fusion
citation_author	Cho, Ken
	Yamashita, Kippei
	Kakutani, Shinnosuke
	Saito, Takuma
	Sasaki, Taisuke
	Sawaizumi, Katsuhiko
	Okugawa, Masayuki
	Koizumi, Yuichiro
	Mayama, Tsuyoshi
	Kikukawa, Taichi
	Gokcekaya, Ozkan
	Ishimoto, Takuya
	Kimizuka, Hajime
	Gong, Wu
	Kawasaki, Takuro
	Harjo, Stefanus
	Nakano, Takayoshi
	Yasuda, Hiroyuki Y.
citation_publisher	Acta Materialia Inc
citation_language	English
citation_date	2025-11-13
citation_journal_title	Acta Materialia
citation_volume	303
citation_firstpage	121696
citation_doi	https://doi.org/10.1016/j.actamat.2025.121696
citation_public_url	https://hdl.handle.net/11094/103524

Effect of nanoscale cellular structure on the mechanical properties of Inconel 718 with unique hierarchical structure fabricated by laser powder bed fusion

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