Hydride formation in two-phase (Ti3Al + TiAl) titanium aluminides during cathodic charging and its dissociation

Akito Takasaki; Kozo Ojima; Youji Taneda

doi:10.1016/0925-8388(94)91032-4

Hydride formation in two-phase (Ti₃Al + TiAl) titanium aluminides during cathodic charging and its dissociation

Akito Takasaki, Kozo Ojima, Youji Taneda

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

14 Citations (Scopus)

Abstract

A (TiAl)H_x hydride which has a tetragonal crystal structure with lattice parameters a = 0.452 nm and c = 0.326 nm (c/a = 0.721) has been observed in Ti42Al, Ti45Al and Ti50Al (at.%) two-phase (Ti₃Al (α₂) + TiAl (γ)) titanium aluminides by cathodic charging in a 5% H₂SO₄ solution. Cracks or pits are also observed within the γ phase regions in the two-phase (α₂ + γ) coexisting grains (such as lamellar grains) but not within the α₂ phase or single γ grains. Weights of the samples decrease with increasing charging time owing to the crack or pit formation, and this is more drastic in the Ti-50Al alloy than in the Ti-42Al and Ti-45Al alloys. The hydride is thermally stable at temperatures up to about 550 K (277 °C) and dissociates completely at temperatures between 673 K (400 °C) and 723 K (450 °C).

Original language	English
Pages (from-to)	1-6
Number of pages	6
Journal	Journal of Alloys and Compounds
Volume	216
Issue number	1
DOIs	https://doi.org/10.1016/0925-8388(94)91032-4
Publication status	Published - 1994 Dec
Externally published	Yes

Keywords

Cathodic charging
Hydride formation
Titanium aluminides

ASJC Scopus subject areas

Mechanics of Materials
Mechanical Engineering
Metals and Alloys
Materials Chemistry

Access to Document

10.1016/0925-8388(94)91032-4

Cite this

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title = "Hydride formation in two-phase (Ti3Al + TiAl) titanium aluminides during cathodic charging and its dissociation",

abstract = "A (TiAl)Hx hydride which has a tetragonal crystal structure with lattice parameters a = 0.452 nm and c = 0.326 nm (c/a = 0.721) has been observed in Ti42Al, Ti45Al and Ti50Al (at.%) two-phase (Ti3Al (α2) + TiAl (γ)) titanium aluminides by cathodic charging in a 5% H2SO4 solution. Cracks or pits are also observed within the γ phase regions in the two-phase (α2 + γ) coexisting grains (such as lamellar grains) but not within the α2 phase or single γ grains. Weights of the samples decrease with increasing charging time owing to the crack or pit formation, and this is more drastic in the Ti-50Al alloy than in the Ti-42Al and Ti-45Al alloys. The hydride is thermally stable at temperatures up to about 550 K (277 °C) and dissociates completely at temperatures between 673 K (400 °C) and 723 K (450 °C).",

keywords = "Cathodic charging, Hydride formation, Titanium aluminides",

author = "Akito Takasaki and Kozo Ojima and Youji Taneda",

year = "1994",

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AU - Takasaki, Akito

AU - Ojima, Kozo

AU - Taneda, Youji

PY - 1994/12

Y1 - 1994/12

N2 - A (TiAl)Hx hydride which has a tetragonal crystal structure with lattice parameters a = 0.452 nm and c = 0.326 nm (c/a = 0.721) has been observed in Ti42Al, Ti45Al and Ti50Al (at.%) two-phase (Ti3Al (α2) + TiAl (γ)) titanium aluminides by cathodic charging in a 5% H2SO4 solution. Cracks or pits are also observed within the γ phase regions in the two-phase (α2 + γ) coexisting grains (such as lamellar grains) but not within the α2 phase or single γ grains. Weights of the samples decrease with increasing charging time owing to the crack or pit formation, and this is more drastic in the Ti-50Al alloy than in the Ti-42Al and Ti-45Al alloys. The hydride is thermally stable at temperatures up to about 550 K (277 °C) and dissociates completely at temperatures between 673 K (400 °C) and 723 K (450 °C).

AB - A (TiAl)Hx hydride which has a tetragonal crystal structure with lattice parameters a = 0.452 nm and c = 0.326 nm (c/a = 0.721) has been observed in Ti42Al, Ti45Al and Ti50Al (at.%) two-phase (Ti3Al (α2) + TiAl (γ)) titanium aluminides by cathodic charging in a 5% H2SO4 solution. Cracks or pits are also observed within the γ phase regions in the two-phase (α2 + γ) coexisting grains (such as lamellar grains) but not within the α2 phase or single γ grains. Weights of the samples decrease with increasing charging time owing to the crack or pit formation, and this is more drastic in the Ti-50Al alloy than in the Ti-42Al and Ti-45Al alloys. The hydride is thermally stable at temperatures up to about 550 K (277 °C) and dissociates completely at temperatures between 673 K (400 °C) and 723 K (450 °C).

KW - Cathodic charging

KW - Hydride formation

KW - Titanium aluminides

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