Depressurization-induced diffusionless transformation in pure iron hydrogenated under several gigapascals

Motomichi Koyama; Hiroyuki Saitoh; Toyoto Sato; Shin ichi Orimo; Eiji Akiyama

doi:10.1016/j.mlblux.2021.100078

Depressurization-induced diffusionless transformation in pure iron hydrogenated under several gigapascals

Motomichi Koyama, Hiroyuki Saitoh, Toyoto Sato, Shin ichi Orimo, Eiji Akiyama

Research output: Contribution to journal › Article › peer-review

2 Citations (Scopus)

Abstract

Phase transformation in hydrogenated iron during depressurization from several gigapascals was investigated through in-situ synchrotron radiation X-ray diffraction and post-mortem electron backscatter diffraction measurements. The hydrogenated iron under 8.6 GPa at 293 K showed a double hexagonal close-packed (dhcp) structure, and it gradually transformed into a body-centered cubic (bcc) structure with decreasing pressure. The final crystal structure consisted entirely of a bcc phase. The structural change from dhcp to bcc structure was diffusionless-type phase transformation. The bcc phase showed lath morphology and could grow during aging under a constant pressure of 1.9 GPa, which indicated that it was bainitic-type transformation that required hydrogen diffusion or desorption.

Original language	English
Article number	100078
Journal	Materials Letters: X
Volume	11
DOIs	https://doi.org/10.1016/j.mlblux.2021.100078
Publication status	Published - 2021 Sept
Externally published	Yes

Keywords

Bainitic transformation
Double hexagonal close-packed structure
High-pressure
Hydrogenation
Pure iron

ASJC Scopus subject areas

Materials Science(all)
Condensed Matter Physics
Mechanics of Materials
Mechanical Engineering

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10.1016/j.mlblux.2021.100078

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title = "Depressurization-induced diffusionless transformation in pure iron hydrogenated under several gigapascals",

abstract = "Phase transformation in hydrogenated iron during depressurization from several gigapascals was investigated through in-situ synchrotron radiation X-ray diffraction and post-mortem electron backscatter diffraction measurements. The hydrogenated iron under 8.6 GPa at 293 K showed a double hexagonal close-packed (dhcp) structure, and it gradually transformed into a body-centered cubic (bcc) structure with decreasing pressure. The final crystal structure consisted entirely of a bcc phase. The structural change from dhcp to bcc structure was diffusionless-type phase transformation. The bcc phase showed lath morphology and could grow during aging under a constant pressure of 1.9 GPa, which indicated that it was bainitic-type transformation that required hydrogen diffusion or desorption.",

keywords = "Bainitic transformation, Double hexagonal close-packed structure, High-pressure, Hydrogenation, Pure iron",

author = "Motomichi Koyama and Hiroyuki Saitoh and Toyoto Sato and Orimo, {Shin ichi} and Eiji Akiyama",

note = "Funding Information: This work was financially supported by JSPS KAKENHI Grants-in-Aid for Scientific Research on innovative areas “Hydrogenomics”, JP20H02457, JP18H05513, and JP18H05514. The synchrotron radiation experiments were performed at QST (JAEA) beamline BL14B1, SPring-8 (2020A-H14), with the approval of JASRI (2020A3691). Publisher Copyright: {\textcopyright} 2021 The Author(s)",

year = "2021",

month = sep,

doi = "10.1016/j.mlblux.2021.100078",

language = "English",

volume = "11",

journal = "Materials Letters: X",

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TY - JOUR

T1 - Depressurization-induced diffusionless transformation in pure iron hydrogenated under several gigapascals

AU - Koyama, Motomichi

AU - Saitoh, Hiroyuki

AU - Sato, Toyoto

AU - Orimo, Shin ichi

AU - Akiyama, Eiji

N1 - Funding Information: This work was financially supported by JSPS KAKENHI Grants-in-Aid for Scientific Research on innovative areas “Hydrogenomics”, JP20H02457, JP18H05513, and JP18H05514. The synchrotron radiation experiments were performed at QST (JAEA) beamline BL14B1, SPring-8 (2020A-H14), with the approval of JASRI (2020A3691). Publisher Copyright: © 2021 The Author(s)

PY - 2021/9

Y1 - 2021/9

N2 - Phase transformation in hydrogenated iron during depressurization from several gigapascals was investigated through in-situ synchrotron radiation X-ray diffraction and post-mortem electron backscatter diffraction measurements. The hydrogenated iron under 8.6 GPa at 293 K showed a double hexagonal close-packed (dhcp) structure, and it gradually transformed into a body-centered cubic (bcc) structure with decreasing pressure. The final crystal structure consisted entirely of a bcc phase. The structural change from dhcp to bcc structure was diffusionless-type phase transformation. The bcc phase showed lath morphology and could grow during aging under a constant pressure of 1.9 GPa, which indicated that it was bainitic-type transformation that required hydrogen diffusion or desorption.

AB - Phase transformation in hydrogenated iron during depressurization from several gigapascals was investigated through in-situ synchrotron radiation X-ray diffraction and post-mortem electron backscatter diffraction measurements. The hydrogenated iron under 8.6 GPa at 293 K showed a double hexagonal close-packed (dhcp) structure, and it gradually transformed into a body-centered cubic (bcc) structure with decreasing pressure. The final crystal structure consisted entirely of a bcc phase. The structural change from dhcp to bcc structure was diffusionless-type phase transformation. The bcc phase showed lath morphology and could grow during aging under a constant pressure of 1.9 GPa, which indicated that it was bainitic-type transformation that required hydrogen diffusion or desorption.

KW - Bainitic transformation

KW - Double hexagonal close-packed structure

KW - High-pressure

KW - Hydrogenation

KW - Pure iron

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ER -

Depressurization-induced diffusionless transformation in pure iron hydrogenated under several gigapascals

Abstract

Keywords

ASJC Scopus subject areas

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