Effect of oxygen absorption on lattice parameter and specimen dilation in a tantalum- base alloy containing 8 Pct tungsten and 2 Pct hafnium

C. T. Liu, H. Inouye, Ray Carpenter

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2 Citations (Scopus)

Abstract

Sheet and tube specimens of a tantalum-base alloy containing 8 Pct tungsten and 2 Pct hafnium (T-111) were exposed to low pressure oxygen at 1000° for the purpose of study-ing the effect of oxygen absorption on lattice parameter and specimen dilation. Oxygen absorption produced an increase in weight and dilation which was proportional to ex-posure time at 1000°. In the as-doped condition, dilation is roughly equal to the lattice expansion, suggesting that the absorbed oxygen is retained mainly in the bec base solu-tion. After isothermal aging at 1400°, the lattice parameter of the as-doped specimen decreases sharply due to the precipitation of HO2 particles; however, the dilation is not affected. The solubility of oxygen in T-lll is calculated to be 64 ppm at 1400°, based on some thermodynamic considerations and lattice parameter measurements. The T-lll specimen dilated 1 Pct after only an 80 h exposure at 1000° at an oxygen pressure of 1.3 x 10-3 Pa (1 × 10-5 Torr). Comparison of creep rates in high vacuum with the dilation rate indicates that specimen dilation due to oxygen absorption is the main reason that causes a higher "creep rate" of refractory alloys in contaminated environ-ments, especially under the conditions of high test temperature and low applied stress.

Original languageEnglish (US)
Pages (from-to)973-978
Number of pages6
JournalMetallurgical Transactions A
Volume9
Issue number7
DOIs
StatePublished - Jul 1978
Externally publishedYes

Fingerprint

Hafnium
Tantalum
Tungsten
hafnium
tantalum
Lattice constants
lattice parameters
tungsten
Oxygen
oxygen
Creep
Refractory alloys
high temperature tests
refractories
high vacuum
solubility
low pressure
Solubility
Aging of materials
Thermodynamics

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Metals and Alloys
  • Mechanics of Materials
  • Engineering(all)

Cite this

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title = "Effect of oxygen absorption on lattice parameter and specimen dilation in a tantalum- base alloy containing 8 Pct tungsten and 2 Pct hafnium",
abstract = "Sheet and tube specimens of a tantalum-base alloy containing 8 Pct tungsten and 2 Pct hafnium (T-111) were exposed to low pressure oxygen at 1000° for the purpose of study-ing the effect of oxygen absorption on lattice parameter and specimen dilation. Oxygen absorption produced an increase in weight and dilation which was proportional to ex-posure time at 1000°. In the as-doped condition, dilation is roughly equal to the lattice expansion, suggesting that the absorbed oxygen is retained mainly in the bec base solu-tion. After isothermal aging at 1400°, the lattice parameter of the as-doped specimen decreases sharply due to the precipitation of HO2 particles; however, the dilation is not affected. The solubility of oxygen in T-lll is calculated to be 64 ppm at 1400°, based on some thermodynamic considerations and lattice parameter measurements. The T-lll specimen dilated 1 Pct after only an 80 h exposure at 1000° at an oxygen pressure of 1.3 x 10-3 Pa (1 × 10-5 Torr). Comparison of creep rates in high vacuum with the dilation rate indicates that specimen dilation due to oxygen absorption is the main reason that causes a higher {"}creep rate{"} of refractory alloys in contaminated environ-ments, especially under the conditions of high test temperature and low applied stress.",
author = "Liu, {C. T.} and H. Inouye and Ray Carpenter",
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AU - Liu, C. T.

AU - Inouye, H.

AU - Carpenter, Ray

PY - 1978/7

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N2 - Sheet and tube specimens of a tantalum-base alloy containing 8 Pct tungsten and 2 Pct hafnium (T-111) were exposed to low pressure oxygen at 1000° for the purpose of study-ing the effect of oxygen absorption on lattice parameter and specimen dilation. Oxygen absorption produced an increase in weight and dilation which was proportional to ex-posure time at 1000°. In the as-doped condition, dilation is roughly equal to the lattice expansion, suggesting that the absorbed oxygen is retained mainly in the bec base solu-tion. After isothermal aging at 1400°, the lattice parameter of the as-doped specimen decreases sharply due to the precipitation of HO2 particles; however, the dilation is not affected. The solubility of oxygen in T-lll is calculated to be 64 ppm at 1400°, based on some thermodynamic considerations and lattice parameter measurements. The T-lll specimen dilated 1 Pct after only an 80 h exposure at 1000° at an oxygen pressure of 1.3 x 10-3 Pa (1 × 10-5 Torr). Comparison of creep rates in high vacuum with the dilation rate indicates that specimen dilation due to oxygen absorption is the main reason that causes a higher "creep rate" of refractory alloys in contaminated environ-ments, especially under the conditions of high test temperature and low applied stress.

AB - Sheet and tube specimens of a tantalum-base alloy containing 8 Pct tungsten and 2 Pct hafnium (T-111) were exposed to low pressure oxygen at 1000° for the purpose of study-ing the effect of oxygen absorption on lattice parameter and specimen dilation. Oxygen absorption produced an increase in weight and dilation which was proportional to ex-posure time at 1000°. In the as-doped condition, dilation is roughly equal to the lattice expansion, suggesting that the absorbed oxygen is retained mainly in the bec base solu-tion. After isothermal aging at 1400°, the lattice parameter of the as-doped specimen decreases sharply due to the precipitation of HO2 particles; however, the dilation is not affected. The solubility of oxygen in T-lll is calculated to be 64 ppm at 1400°, based on some thermodynamic considerations and lattice parameter measurements. The T-lll specimen dilated 1 Pct after only an 80 h exposure at 1000° at an oxygen pressure of 1.3 x 10-3 Pa (1 × 10-5 Torr). Comparison of creep rates in high vacuum with the dilation rate indicates that specimen dilation due to oxygen absorption is the main reason that causes a higher "creep rate" of refractory alloys in contaminated environ-ments, especially under the conditions of high test temperature and low applied stress.

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