Please use this identifier to cite or link to this item: http://hdl.handle.net/10995/111979
Title: Unusual Two-Step Dealloying Mechanism of Nanoporous TiVNbMoTa High-Entropy Alloy During Liquid Metal Dealloying
Authors: Joo, S. -H.
Okulov, I. V.
Kato, H.
Issue Date: 2021
Publisher: Elsevier Editora Ltda
Elsevier BV
Citation: Joo S. -H. Unusual Two-Step Dealloying Mechanism of Nanoporous TiVNbMoTa High-Entropy Alloy During Liquid Metal Dealloying / S. -H. Joo, I. V. Okulov, H. Kato // Journal of Materials Research and Technology. — 2021. — Vol. 14. — P. 2945-2953.
Abstract: In this study, 3D interconnected nanoporous (3DNP) TiVNbMoTa HEAs were synthesized from the (TiVNbMoTa)25Ni75 as-cast precursor alloy using the liquid metal dealloying (LMD). The as-cast precursor demonstrated the initial dendritic microstructure consisting of fcc and hcp phases. At 600 °C after 1 h, tiny ligaments about 10 nm thickness were homogeneously synthesized. At 900 °C, the bulk transformation intensively took place at the original precursor alloy. Specifically, the dendritic morphology of the original phases disappeared, and the fraction of fcc phase decreased from 63% to 20%. This pre-transformation behavior significantly influences the dealloying mechanism. Kurdjumov–Sachs orientation relationship (OR) governed the ligament formation at the prior fcc phase while Pitsch-Schrader (P–S) OR controlled the ligament evolution at the prior hcp phase. An unusual mechanism of two-step dealloying was observed at the fcc phase region when the dealloying rate was decreased at the reaction front. The dissolution of Ni occurs by stepwise transformations of fcc=>hcp=>bcc. The prior fcc grain was transformed to the abnormally large hcp ligaments and tiny bcc ligaments. Then, the abnormal hcp ligaments were further dealloyed to smaller bcc ligaments following the P–S OR. This study pave the way for the design of compositionally complex porous materials with a customized morphology and advanced physical properties by dealloying. © 2021 The Authors.
Keywords: ABNORMAL TRANSFORMATION
DEALLOYING MECHANISM
HIGH-ENTROPY ALLOY
LIQUID METAL DEALLOYING
NANOPOROUS
DEALLOYING
ENTROPY
HIGH-ENTROPY ALLOYS
MORPHOLOGY
NIOBIUM ALLOYS
POROUS MATERIALS
TANTALUM ALLOYS
TITANIUM ALLOYS
ZIRCALOY
ABNORMAL TRANSFORMATION
AS-CAST
DEALLOYING
DEALLOYING MECHANISM
FCC PHASE
HIGH ENTROPY ALLOYS
LIQUID METAL DEALLOYING
NANO-POROUS
PRECURSOR ALLOYS
SYNTHESISED
LIQUID METALS
URI: http://hdl.handle.net/10995/111979
Access: info:eu-repo/semantics/openAccess
SCOPUS ID: 85114370459
PURE ID: 23739479
ISSN: 2238-7854
metadata.dc.description.sponsorship: This work has supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. NRF-2021R1C1C1007645 ). I.V. Okulov acknowledges support from German Science Foundation under the Leibniz Program (Grant MA 3333/13-1 ).
Appears in Collections:Научные публикации, проиндексированные в SCOPUS и WoS CC

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