Ab initio stability prediction of β titanium and α and ω precipitates in β titanium matrix for titanium alloys using density functional theory and micromechanics

Ishii, Akio

doi:https://doi.org/10.1016/j.mtcomm.2023.107708

Ab initio stability prediction of β titanium and α and ω precipitates in β titanium matrix for titanium alloys using density functional theory and micromechanics

Ishii, Akio

Materials Today Communications, 2023, 62, 107708

Number of Access:284（2025-08-29 05:24 Counts）

Identifier to cite or link to this item: https://hdl.handle.net/11094/93219

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Title	Ab initio stability prediction of β titanium and α and ω precipitates in β titanium matrix for titanium alloys using density functional theory and micromechanics
Creator	NRID 1000080773340 1000080773340 researchmap permalink a_ishii a_ishii ORCID 0000-0002-9369-6259 0000-0002-9369-6259 Scopus Author ID 7201558020 7201558020 CreatorName Ishii, Akio
Subject	Titanium alloy
	Eshelby’s ellipsoidal inclusion
	Atomistic simulation
	Density functional theory
Abstract	𝛽 titanium alloys have a wide range of applications, including in aerospace and transport. The 𝛽 phase is stable only at high temperatures, and the phase stability can be improved by adding stabilizers. However, the 𝛽 -phase-stabilization effects of 𝛽 stabilizers have not yet been clearly elucidated. Here, I report the 𝑎𝑏 𝑖𝑛𝑖𝑡𝑖𝑜 prediction of the energetic phase stability of 𝛽 titanium alloys with Mo, V, W, Nb, and Ta as additive 𝛽 stabilizer elements. The stability is predicted using a combination of atomistic simulation via density functional theory and continuum micromechanics (Eshelby’s ellipsoidal inclusion analysis). In particular, I consider the heterogeneity of the secondary 𝜔 and α phases (precipitation) in the 𝛽 matrix. All 𝛽 stabilizer species led to a significant energetic and elastic stabilization of the 𝛽 phase. Mo and W additives stabilized the 𝛽 phase relatively stronger and secondary 𝜔 and α precipitates may hardly nucleate in 𝛽 phase in high concentrate condition. Although V, Nb, and Ta additives stabilized the 𝛽 phase significantly, the 𝛽 phase remained metastable. Regarding the morphology of these secondary phases, V helped α precipitation and Ta helped 𝜔 precipitation. The possibility of a coexistence of 𝜔 and α in the 𝛽 matrix was suggested for Nb addition. The strain fields around the precipitates were also investigated and the results suggested that α precipitates cause a large residual strain around it though 𝜔 precipitates do not.
Publisher	Elsevier BV
Source Title	Materials Today Communications
Volume (Issue)	62
Page	107708
Date of Issued	2023-11-28
Handle URL	https://hdl.handle.net/11094/93219
PISSN	23524928
Relation.isVersionOf	DOI (Publisher Version) https://doi.org/10.1016/j.mtcomm.2023.107708
Access Rights	open access
oaire:version	Author’s Original
Category	学術雑誌論文 Journal Article

Resource Type	journal article
Local Type	Journal Article
DCMI Type	Text
DCTERMS.bibliographicCitation	Materials Today Communications. 2023, 62, p. 107708
DC.title	Ab initio stability prediction of β titanium and α and ω precipitates in β titanium matrix for titanium alloys using density functional theory and micromechanics
DC.creator	Ishii, Akio
DC.publisher	Elsevier BV
DC.type' scheme='DCTERMS.DCMIType	Text
DCTERMS.issued' scheme='DCTERMS.W3CDTF	2023-11-28
DC.identifier	https://doi.org/10.1016/j.mtcomm.2023.107708
DC.subject	Titanium alloy
	Eshelby’s ellipsoidal inclusion
	Atomistic simulation
	Density functional theory
DCTERMS.abstract	𝛽 titanium alloys have a wide range of applications, including in aerospace and transport. The 𝛽 phase is stable only at high temperatures, and the phase stability can be improved by adding stabilizers. However, the 𝛽 -phase-stabilization effects of 𝛽 stabilizers have not yet been clearly elucidated. Here, I report the 𝑎𝑏 𝑖𝑛𝑖𝑡𝑖𝑜 prediction of the energetic phase stability of 𝛽 titanium alloys with Mo, V, W, Nb, and Ta as additive 𝛽 stabilizer elements. The stability is predicted using a combination of atomistic simulation via density functional theory and continuum micromechanics (Eshelby’s ellipsoidal inclusion analysis). In particular, I consider the heterogeneity of the secondary 𝜔 and α phases (precipitation) in the 𝛽 matrix. All 𝛽 stabilizer species led to a significant energetic and elastic stabilization of the 𝛽 phase. Mo and W additives stabilized the 𝛽 phase relatively stronger and secondary 𝜔 and α precipitates may hardly nucleate in 𝛽 phase in high concentrate condition. Although V, Nb, and Ta additives stabilized the 𝛽 phase significantly, the 𝛽 phase remained metastable. Regarding the morphology of these secondary phases, V helped α precipitation and Ta helped 𝜔 precipitation. The possibility of a coexistence of 𝜔 and α in the 𝛽 matrix was suggested for Nb addition. The strain fields around the precipitates were also investigated and the results suggested that α precipitates cause a large residual strain around it though 𝜔 precipitates do not.
DC.format	93219
citation_title	Ab initio stability prediction of β titanium and α and ω precipitates in β titanium matrix for titanium alloys using density functional theory and micromechanics
citation_author	Ishii, Akio
citation_publisher	Elsevier BV
citation_date	2023-11-28
citation_journal_title	Materials Today Communications
citation_volume	62
citation_firstpage	107708
citation_doi	https://doi.org/10.1016/j.mtcomm.2023.107708
citation_public_url	https://hdl.handle.net/11094/93219

Ab initio stability prediction of β titanium and α and ω precipitates in β titanium matrix for titanium alloys using density functional theory and micromechanics

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