Peculiar microstructural evolution and tensile properties of β-containing γ-TiAl alloys fabricated by electron beam melting

Cho, Ken; Kawabata, Hajime; Hayashi, Tatsuhiro; Yasuda, Hiroyuki Y.; Nakashima, Hirotoyo; Takeyama, Masao; Nakano, Takayoshi

doi:https://doi.org/10.1016/j.addma.2021.102091

Peculiar microstructural evolution and tensile properties of β-containing γ-TiAl alloys fabricated by electron beam melting

Cho, Ken; Kawabata, Hajime; Hayashi, Tatsuhiro et al.

Additive Manufacturing, 2021, 46, 102091

Number of Access:692（2025-08-14 06:13 Counts）

Identifier to cite or link to this item: https://hdl.handle.net/11094/89768

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Title	Peculiar microstructural evolution and tensile properties of β-containing γ-TiAl alloys fabricated by electron beam melting
Creator	NRID 1000000633661 1000000633661 researchmap permalink choken choken Scopus Author ID 55535308400 55535308400 CreatorName Cho, Ken
	CreatorName Kawabata, Hajime
	CreatorName Hayashi, Tatsuhiro
	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.
	CreatorName Nakashima, Hirotoyo
	CreatorName Takeyama, Masao
	NRID 1000030243182 1000030243182 ORCID 0000-0001-8052-1698 0000-0001-8052-1698 researchmap permalink read0013987 read0013987 Scopus Author ID 7403896013 7403896013 CreatorName Nakano, Takayoshi
Subject	Additive manufacturing
	Electron beam melting
	Microstructure
	Tensile properties
	Titanium aluminide
Description	Cho K., Kawabata H., Hayashi T., et al. Peculiar microstructural evolution and tensile properties of β-containing γ-TiAl alloys fabricated by electron beam melting. Additive Manufacturing, 46, 102091. https://doi.org/10.1016/j.addma.2021.102091.
Abstract	The microstructure and tensile properties of β-containing Ti–44Al–4Cr alloy rods additively manufactured by electron beam melting (EBM) process were examined as a function of input energy density determined by the processing parameters. To the best of our knowledge, this is the first report to demonstrate that two types of fine microstructures have been obtained in the β-containing γ-TiAl alloys by varying the energy density during the EBM process. A uniform α2/β/γ mixed structure containing an α2/γ lamellar region and a β/γ dual-phase region is formed at high energy density conditions. On the other hand, a lower energy density leads to the formation of a peculiar layered microstructure perpendicular to the building direction, consisting of a ultrafine α2/γ lamellar grain layer and a α2/β/γ mixed structure layer. The difference in the microstructures originates from the difference in the solidification microstructure and the temperature distribution from the melt pool, which are dependent on the energy density. Furthermore, it was found that the strength of the alloys is closely related to the volume fractions of the β phase and the ultrafine α2/γ lamellar grains which originates from the massive α grains formed by rapid cooling under low energy density conditions. The alloys with high amounts of these peculiar microstructures exhibit high strength comparable to and higher than the conventional β-containing γ-TiAl at room temperature and 1023 K, respectively.
Publisher	Elsevier
Source Title	Additive Manufacturing
Volume (Issue)	46
Page	102091
Date of Issued	2021-10-01
Language	English
Handle URL	https://hdl.handle.net/11094/89768
eISSN	22148604
Relation.isIdenticalTo	DOI (Publisher Version) https://doi.org/10.1016/j.addma.2021.102091
Access Rights	open access
CopyRight	This article is licensed under a Creative Commons Attribution 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	Additive Manufacturing. 2021, 46, p. 102091
DC.title	Peculiar microstructural evolution and tensile properties of β-containing γ-TiAl alloys fabricated by electron beam melting
DC.creator	Cho, Ken
	Kawabata, Hajime
	Hayashi, Tatsuhiro
	Yasuda, Hiroyuki Y.
	Nakashima, Hirotoyo
	Takeyama, Masao
	Nakano, Takayoshi
DC.publisher	Elsevier
DC.language' scheme='DCTERMS.RFC1766	English
DC.type' scheme='DCTERMS.DCMIType	Text
DCTERMS.issued' scheme='DCTERMS.W3CDTF	2021-10-01
DC.identifier	https://doi.org/10.1016/j.addma.2021.102091
DC.subject	Additive manufacturing
	Electron beam melting
	Microstructure
	Tensile properties
	Titanium aluminide
DC.description	Cho K., Kawabata H., Hayashi T., et al. Peculiar microstructural evolution and tensile properties of β-containing γ-TiAl alloys fabricated by electron beam melting. Additive Manufacturing, 46, 102091. https://doi.org/10.1016/j.addma.2021.102091.
DCTERMS.abstract	The microstructure and tensile properties of β-containing Ti–44Al–4Cr alloy rods additively manufactured by electron beam melting (EBM) process were examined as a function of input energy density determined by the processing parameters. To the best of our knowledge, this is the first report to demonstrate that two types of fine microstructures have been obtained in the β-containing γ-TiAl alloys by varying the energy density during the EBM process. A uniform α2/β/γ mixed structure containing an α2/γ lamellar region and a β/γ dual-phase region is formed at high energy density conditions. On the other hand, a lower energy density leads to the formation of a peculiar layered microstructure perpendicular to the building direction, consisting of a ultrafine α2/γ lamellar grain layer and a α2/β/γ mixed structure layer. The difference in the microstructures originates from the difference in the solidification microstructure and the temperature distribution from the melt pool, which are dependent on the energy density. Furthermore, it was found that the strength of the alloys is closely related to the volume fractions of the β phase and the ultrafine α2/γ lamellar grains which originates from the massive α grains formed by rapid cooling under low energy density conditions. The alloys with high amounts of these peculiar microstructures exhibit high strength comparable to and higher than the conventional β-containing γ-TiAl at room temperature and 1023 K, respectively.
DC.rights	This article is licensed under a Creative Commons Attribution 4.0 International License.
DC.format	89768
citation_title	Peculiar microstructural evolution and tensile properties of β-containing γ-TiAl alloys fabricated by electron beam melting
citation_author	Cho, Ken
	Kawabata, Hajime
	Hayashi, Tatsuhiro
	Yasuda, Hiroyuki Y.
	Nakashima, Hirotoyo
	Takeyama, Masao
	Nakano, Takayoshi
citation_publisher	Elsevier
citation_language	English
citation_date	2021-10-01
citation_journal_title	Additive Manufacturing
citation_volume	46
citation_firstpage	102091
citation_doi	https://doi.org/10.1016/j.addma.2021.102091
citation_public_url	https://hdl.handle.net/11094/89768

Peculiar microstructural evolution and tensile properties of β-containing γ-TiAl alloys fabricated by electron beam melting

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