Effects of hatch spacing on densification, microstructural and mechanical properties of β-solidifying γ-TiAl alloy fabricated by laser powder bed fusion

Park, Sung Hyun; Gokcekaya, Ozkan; Oh, Myung Hoon; Nakano, Takayoshi

doi:https://doi.org/10.1016/j.matchar.2024.114077

Effects of hatch spacing on densification, microstructural and mechanical properties of β-solidifying γ-TiAl alloy fabricated by laser powder bed fusion

Park, Sung Hyun; Gokcekaya, Ozkan; Oh, Myung Hoon et al.

Materials Characterization, 2024, 214, 114077

Number of Access:342（2025-08-21 04:36 Counts）

Identifier to cite or link to this item: https://hdl.handle.net/11094/97657

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Title	Effects of hatch spacing on densification, microstructural and mechanical properties of β-solidifying γ-TiAl alloy fabricated by laser powder bed fusion
Creator	CreatorName Park, Sung Hyun
	NRID 1000050988160 1000050988160 ORCID 0000-0002-9258-858X 0000-0002-9258-858X Scopus Author ID 37051975500 37051975500 CreatorName Gokcekaya, Ozkan
	CreatorName Oh, Myung Hoon
	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	Densification
	Hatch spacing
	Laser powder bed fusion
	Mechanical properties
	Microstructure evolution
	γ-TiAl alloy
Description	Park S.H., Gokcekaya O., Oh M.H., et al. Effects of hatch spacing on densification, microstructural and mechanical properties of β-solidifying γ-TiAl alloy fabricated by laser powder bed fusion. Materials Characterization 214, 114077 (2024); https://doi.org/10.1016/j.matchar.2024.114077.
Abstract	β-solidifying γ‑titanium aluminide (γ-TiAl) alloys, which typically contain β-phase stabilizers such as Nb and Cr, hold great promise for the aerospace industry and can potentially be processed through additive manufacturing to realize performance unachievable using conventional methods. However, the effects of laser powder bed fusion (L-PBF) parameters on the characteristics of the thus obtained samples remain underexplored. To address this gap, we herein examined the effects of hatch spacing on the densification, microstructural, and mechanical properties of L-PBF-fabricated Ti-44Al-6Nb-1.2Cr (at.%) alloy samples, revealing that the strong influence on thermal history induced the variation in densification and formation of two microstructure types. 0.01 mm hatch spacing resulted in repetitive slow cooling and sufficiently remelting, thus suppressing crack formation, promoting high densification, and inducing a complex phase transformation involving the formation of a basket-weave-structured α₂ phase and the 〈001〉 alignment of the β phase along the build direction. 0.06 mm hatch spacing resulted in rapid cooling and insufficient heat accumulation, favoring the massive phase transformation, a jagged morphology α₂ phase with a randomly distributed crystallographic texture. Hardness was mainly correlated with phase constitution and volume fraction, whereas compressive properties were jointly determined by additional effects of multiple factors such as grain size and crystallographic texture. This work provides the fundamental insights required to suppress defect formation in β-solidifying γ-TiAl alloys and tailor their microstructure for mechanical property enhancement.
Publisher	Elsevier Inc.
Source Title	Materials Characterization
Volume (Issue)	214
Page	114077
Date of Issued	2024-08-01
Language	English
Handle URL	https://hdl.handle.net/11094/97657
PISSN	10445803
Relation.isIdenticalTo	DOI (Publisher Version) https://doi.org/10.1016/j.matchar.2024.114077
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
DCTERMS.bibliographicCitation	Materials Characterization. 2024, 214, p. 114077
DC.title	Effects of hatch spacing on densification, microstructural and mechanical properties of β-solidifying γ-TiAl alloy fabricated by laser powder bed fusion
DC.creator	Park, Sung Hyun
	Gokcekaya, Ozkan
	Oh, Myung Hoon
	Nakano, Takayoshi
DC.publisher	Elsevier Inc.
DC.language' scheme='DCTERMS.RFC1766	English
DCTERMS.issued' scheme='DCTERMS.W3CDTF	2024-08-01
DC.identifier	https://doi.org/10.1016/j.matchar.2024.114077
DC.subject	Densification
	Hatch spacing
	Laser powder bed fusion
	Mechanical properties
	Microstructure evolution
	γ-TiAl alloy
DC.description	Park S.H., Gokcekaya O., Oh M.H., et al. Effects of hatch spacing on densification, microstructural and mechanical properties of β-solidifying γ-TiAl alloy fabricated by laser powder bed fusion. Materials Characterization 214, 114077 (2024); https://doi.org/10.1016/j.matchar.2024.114077.
DCTERMS.abstract	β-solidifying γ‑titanium aluminide (γ-TiAl) alloys, which typically contain β-phase stabilizers such as Nb and Cr, hold great promise for the aerospace industry and can potentially be processed through additive manufacturing to realize performance unachievable using conventional methods. However, the effects of laser powder bed fusion (L-PBF) parameters on the characteristics of the thus obtained samples remain underexplored. To address this gap, we herein examined the effects of hatch spacing on the densification, microstructural, and mechanical properties of L-PBF-fabricated Ti-44Al-6Nb-1.2Cr (at.%) alloy samples, revealing that the strong influence on thermal history induced the variation in densification and formation of two microstructure types. 0.01 mm hatch spacing resulted in repetitive slow cooling and sufficiently remelting, thus suppressing crack formation, promoting high densification, and inducing a complex phase transformation involving the formation of a basket-weave-structured α₂ phase and the 〈001〉 alignment of the β phase along the build direction. 0.06 mm hatch spacing resulted in rapid cooling and insufficient heat accumulation, favoring the massive phase transformation, a jagged morphology α₂ phase with a randomly distributed crystallographic texture. Hardness was mainly correlated with phase constitution and volume fraction, whereas compressive properties were jointly determined by additional effects of multiple factors such as grain size and crystallographic texture. This work provides the fundamental insights required to suppress defect formation in β-solidifying γ-TiAl alloys and tailor their microstructure for mechanical property enhancement.
DC.rights	This article is licensed under a Creative Commons Attribution 4.0 International License.
DC.format	97657
citation_title	Effects of hatch spacing on densification, microstructural and mechanical properties of β-solidifying γ-TiAl alloy fabricated by laser powder bed fusion
citation_author	Park, Sung Hyun
	Gokcekaya, Ozkan
	Oh, Myung Hoon
	Nakano, Takayoshi
citation_publisher	Elsevier Inc.
citation_language	English
citation_date	2024-08-01
citation_journal_title	Materials Characterization
citation_volume	214
citation_firstpage	114077
citation_doi	https://doi.org/10.1016/j.matchar.2024.114077
citation_public_url	https://hdl.handle.net/11094/97657

Effects of hatch spacing on densification, microstructural and mechanical properties of β-solidifying γ-TiAl alloy fabricated by laser powder bed fusion

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