Thermodynamic analysis of the Ti-Zr-H ternary phase diagram

Shusuke Ukita; Hiroshi Ohtani; Mitsuhiro Hasebe

Thermodynamic analysis of the Ti-Zr-H ternary phase diagram

Shusuke Ukita, Hiroshi Ohtani, Mitsuhiro Hasebe

Research output: Contribution to journal › Conference article › peer-review

Abstract

A thermodynamic analysis of the Ti-Zr-H ternary system has been performed by combining first-principles calculations with the CALPHAD approach. To enable the thermodynamic description of the binary systems, the results from our previous evaluation were adopted for the Ti-H, Zr-H, and Ti-Zr systems. The ternary compound, Ti₂ZrH₄, with an Fd3̄m -type crystal structure, exists over a wide composition range, and the (Ti) ₂(Zr)₁(H,Va)₄-type three-sublattice model was applied to describe its thermodynamic properties. Because of the lack of experimental information available, the enthalpy of formation of the Ti ₂ZrH₄ phase was evaluated using the Full Potential Linearized Augmented Plane Wave method, and the estimated values were introduced into a CALPHAD-type thermodynamic analysis with some other experimental information. The calculated phase diagrams and the hydrogen isotherms were in good accordance with previous experimental results. Our calculations revealed that the ternary compound decomposes into a bcc and gas phase in the vicinity of 1270K.

Original language	English
Pages (from-to)	989-992
Number of pages	4
Journal	Advanced Materials Research
Volume	24-25
Publication status	Published - 2007 Jan 1
Externally published	Yes
Event	PRICM 6: The 6th Pacific Rim International Conference on Advanced Materials and Processing - Jeju Island, Korea, Republic of Duration: 2007 Nov 5 → 2007 Nov 9

Keywords

Hydrogen storage alloys
Ternary hydride
Thermodynamic analysis

ASJC Scopus subject areas

Engineering(all)

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@article{e1185356a0644a92b920dda0bc31da16,

title = "Thermodynamic analysis of the Ti-Zr-H ternary phase diagram",

abstract = "A thermodynamic analysis of the Ti-Zr-H ternary system has been performed by combining first-principles calculations with the CALPHAD approach. To enable the thermodynamic description of the binary systems, the results from our previous evaluation were adopted for the Ti-H, Zr-H, and Ti-Zr systems. The ternary compound, Ti2ZrH4, with an Fd{\=3}m -type crystal structure, exists over a wide composition range, and the (Ti) 2(Zr)1(H,Va)4-type three-sublattice model was applied to describe its thermodynamic properties. Because of the lack of experimental information available, the enthalpy of formation of the Ti 2ZrH4 phase was evaluated using the Full Potential Linearized Augmented Plane Wave method, and the estimated values were introduced into a CALPHAD-type thermodynamic analysis with some other experimental information. The calculated phase diagrams and the hydrogen isotherms were in good accordance with previous experimental results. Our calculations revealed that the ternary compound decomposes into a bcc and gas phase in the vicinity of 1270K.",

keywords = "Hydrogen storage alloys, Ternary hydride, Thermodynamic analysis",

author = "Shusuke Ukita and Hiroshi Ohtani and Mitsuhiro Hasebe",

year = "2007",

month = jan,

day = "1",

language = "English",

volume = "24-25",

pages = "989--992",

journal = "Advanced Materials Research",

issn = "1022-6680",

publisher = "Trans Tech Publications",

note = "PRICM 6: The 6th Pacific Rim International Conference on Advanced Materials and Processing ; Conference date: 05-11-2007 Through 09-11-2007",

}

TY - JOUR

T1 - Thermodynamic analysis of the Ti-Zr-H ternary phase diagram

AU - Ukita, Shusuke

AU - Ohtani, Hiroshi

AU - Hasebe, Mitsuhiro

PY - 2007/1/1

Y1 - 2007/1/1

N2 - A thermodynamic analysis of the Ti-Zr-H ternary system has been performed by combining first-principles calculations with the CALPHAD approach. To enable the thermodynamic description of the binary systems, the results from our previous evaluation were adopted for the Ti-H, Zr-H, and Ti-Zr systems. The ternary compound, Ti2ZrH4, with an Fd3̄m -type crystal structure, exists over a wide composition range, and the (Ti) 2(Zr)1(H,Va)4-type three-sublattice model was applied to describe its thermodynamic properties. Because of the lack of experimental information available, the enthalpy of formation of the Ti 2ZrH4 phase was evaluated using the Full Potential Linearized Augmented Plane Wave method, and the estimated values were introduced into a CALPHAD-type thermodynamic analysis with some other experimental information. The calculated phase diagrams and the hydrogen isotherms were in good accordance with previous experimental results. Our calculations revealed that the ternary compound decomposes into a bcc and gas phase in the vicinity of 1270K.

AB - A thermodynamic analysis of the Ti-Zr-H ternary system has been performed by combining first-principles calculations with the CALPHAD approach. To enable the thermodynamic description of the binary systems, the results from our previous evaluation were adopted for the Ti-H, Zr-H, and Ti-Zr systems. The ternary compound, Ti2ZrH4, with an Fd3̄m -type crystal structure, exists over a wide composition range, and the (Ti) 2(Zr)1(H,Va)4-type three-sublattice model was applied to describe its thermodynamic properties. Because of the lack of experimental information available, the enthalpy of formation of the Ti 2ZrH4 phase was evaluated using the Full Potential Linearized Augmented Plane Wave method, and the estimated values were introduced into a CALPHAD-type thermodynamic analysis with some other experimental information. The calculated phase diagrams and the hydrogen isotherms were in good accordance with previous experimental results. Our calculations revealed that the ternary compound decomposes into a bcc and gas phase in the vicinity of 1270K.

KW - Hydrogen storage alloys

KW - Ternary hydride

KW - Thermodynamic analysis

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M3 - Conference article

AN - SCOPUS:57649095218

VL - 24-25

SP - 989

EP - 992

JO - Advanced Materials Research

JF - Advanced Materials Research

SN - 1022-6680

T2 - PRICM 6: The 6th Pacific Rim International Conference on Advanced Materials and Processing

Y2 - 5 November 2007 through 9 November 2007

ER -