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Title: Biaxial Thermal Creep of Two Heats of V 4Cr 4Ti at 700 and 800 C in a Liquid Lithium Environment

Abstract

This paper presents biaxial thermal creep results for the vanadium alloy V4Cr4Ti in liquid lithium using US Heat 832665 and two batches of tubing made from NIFS-Heat-2. The tests were performed at 700 and 800 C over a stress range of 30-120 MPa using pressurized tube specimens. Lithium environments changed C, N and O concentrations in V4Cr4Ti. Oxygen removal from the alloy to lithium was small when there was a significant pickup of nitrogen during exposures. The creep response of V4Cr4Ti was characterized by an inverted primary creep followed by a secondary creep or an accelerating creep up to creep rupture. A normal primary creep was also observed in US Heat 832665 when tested at 700 C and 120 MPa. Improved creep rupture properties were observed in the JP-NIFS-Heat-2 specimens compared to the US-NIFS-Heat-2 specimens. Creep response of V4Cr4Ti is apparently dependent on the heat, tubing production, and stress and temperature conditions.

Authors:
 [1];  [2];  [1];  [1];  [1];  [2];  [3];  [4];  [5]
  1. ORNL
  2. National Institute for Fusion Science, Toki, Japan
  3. University of Fukui, Fukui, Japan
  4. Institute for Materials Research, Tohoku University, Sendai, Japan
  5. Tohoku University, Ibaraki, Japan
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
966068
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Nuclear Materials; Journal Volume: 367-370; Journal Issue: 1
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALLOYS; CREEP; LITHIUM; NITROGEN; OXYGEN; PRODUCTION; REMOVAL; RUPTURES; VANADIUM ALLOYS

Citation Formats

Li, Meimei, Nagasaka, Takuya, Hoelzer, David T, Grossbeck, Martin L, Zinkle, Steven J, Muroga, Takeo, Fukumoto, Ken-ichi, Matsui, Hideki, and Narui, Manoru. Biaxial Thermal Creep of Two Heats of V4Cr4Ti at 700 and 800 C in a Liquid Lithium Environment. United States: N. p., 2007. Web. doi:10.1016/j.jnucmat.2007.03.081.
Li, Meimei, Nagasaka, Takuya, Hoelzer, David T, Grossbeck, Martin L, Zinkle, Steven J, Muroga, Takeo, Fukumoto, Ken-ichi, Matsui, Hideki, & Narui, Manoru. Biaxial Thermal Creep of Two Heats of V4Cr4Ti at 700 and 800 C in a Liquid Lithium Environment. United States. doi:10.1016/j.jnucmat.2007.03.081.
Li, Meimei, Nagasaka, Takuya, Hoelzer, David T, Grossbeck, Martin L, Zinkle, Steven J, Muroga, Takeo, Fukumoto, Ken-ichi, Matsui, Hideki, and Narui, Manoru. Mon . "Biaxial Thermal Creep of Two Heats of V4Cr4Ti at 700 and 800 C in a Liquid Lithium Environment". United States. doi:10.1016/j.jnucmat.2007.03.081.
@article{osti_966068,
title = {Biaxial Thermal Creep of Two Heats of V4Cr4Ti at 700 and 800 C in a Liquid Lithium Environment},
author = {Li, Meimei and Nagasaka, Takuya and Hoelzer, David T and Grossbeck, Martin L and Zinkle, Steven J and Muroga, Takeo and Fukumoto, Ken-ichi and Matsui, Hideki and Narui, Manoru},
abstractNote = {This paper presents biaxial thermal creep results for the vanadium alloy V4Cr4Ti in liquid lithium using US Heat 832665 and two batches of tubing made from NIFS-Heat-2. The tests were performed at 700 and 800 C over a stress range of 30-120 MPa using pressurized tube specimens. Lithium environments changed C, N and O concentrations in V4Cr4Ti. Oxygen removal from the alloy to lithium was small when there was a significant pickup of nitrogen during exposures. The creep response of V4Cr4Ti was characterized by an inverted primary creep followed by a secondary creep or an accelerating creep up to creep rupture. A normal primary creep was also observed in US Heat 832665 when tested at 700 C and 120 MPa. Improved creep rupture properties were observed in the JP-NIFS-Heat-2 specimens compared to the US-NIFS-Heat-2 specimens. Creep response of V4Cr4Ti is apparently dependent on the heat, tubing production, and stress and temperature conditions.},
doi = {10.1016/j.jnucmat.2007.03.081},
journal = {Journal of Nuclear Materials},
number = 1,
volume = 367-370,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • A study of the thermal creep properties of V-4Cr-4Ti was performed using pressurized tube specimens. Creep tubes nominally 4.57 mm OD by 0.25 mm wall thickness were pressurized with high-purity helium gas to mid-wall effective stresses below the uniaxial yield strength. Specimens were heated to 700 and 800?C in an ultra-high vacuum furnace and periodically removed to measure the change in OD with a high-precision laser profilometer. The secondary creep rate was found to be power-law dependent on the applied stress with a stress exponent of 3.7 at 700?C and 2.7 at 800?C. The average activation energy for creep ofmore » V-4Cr-4Ti was 299 kJ/mole, which is quite close to the activation energy for self-diffusion in pure vanadium in this temperature regime. The predominant mechanism of creep deformation for the conditions employed in this study is most likely climb assisted dislocation motion.« less
  • Microstructural examination have been performed on irradiation-creep pressurized tube specimens of V-3Fe-4Ti-0.1 Si in order to understand failure and creep mechanisms.
  • Ni{sub 2}(C{sub 4}H{sub 4}N{sub 2})(V{sub 4}O{sub 12})(H{sub 2}O){sub 2}, 1, and Ni{sub 3}(C{sub 4}H{sub 4}N{sub 2}){sub 3}(V{sub 8}O{sub 23}), 2, have been synthesized using mild hydrothermal conditions at 170 deg. C under autogenous pressure. Both phases crystallize in the P-1 triclinic space group, with the unit-cell parameters, a=7.437(7), b=7.571(3), c=7.564(4) A, {alpha}=65.64(4), {beta}=76.09(4), {gamma}=86.25(3){sup o} for 1 and a=8.566(2), b=9.117(2), c=12.619(3) A, {alpha}=71.05(2), {beta}=83.48(4), {gamma}=61.32(3){sup o} for 2, being Z=2 for both compounds. The crystal structure of the three-dimensional 1 is constructed from layers linked between them through the pyrazine molecules. The sheets are formed by edge-shared [Ni{sub 2}O{sub 6}(H{submore » 2}O){sub 2}N{sub 2}] nickel(II) dimers octahedra and rings composed by four [V{sub 4}O{sub 12}] vanadium(V) tetrahedra linked through vertices. The crystal structure of 2 is formed from vertex shared [VO{sub 4}] tetrahedra that give rise to twelve member rings. [NiO{sub 4}(C{sub 4}H{sub 4}N{sub 2}){sub 2}]{sub {infinity}} chains, resulting from [NiO{sub 4}N{sub 2}] octahedra and pyrazine molecules, give rise to a 3D skeleton when connecting to [VO{sub 4}] tetrahedra. Diffuse reflectance measurements of 1 indicate a slightly distorted octahedral geometry with values of Dq=880, B=980 and C=2700 cm{sup -1}. Magnetic measurements of 1, carried out in the 5.0-300 K range, indicate the existence of antiferromagnetic couplings with a Neel temperature near to 38 K. - Graphical abstract: Crystal structure of a sheet of Ni{sub 2}(C{sub 4}H{sub 4}N{sub 2})(V{sub 4}O{sub 12})(H{sub 2}O){sub 2}.« less
  • Nanocrystalline TiN, VN and CrN have been synthesized by a thermal nitridation reaction between the corresponding metal powder and NH{sub 4}Cl at 600 deg. C in an autoclave. X-ray powders diffraction (XRD) indicated that these nanocystallites had a NaCl-type structure with lattice parameters: a=4.236 A for TiN, 4.133 A for VN, 4.145 A for CrN. Transmission electron microscopy (TEM) showed these products consisted of cubic nanocrystals. X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) techniques revealed that all the products were almost pure nitrides.
  • Reaction of the trivanadium-substituted polyoxometalates (Bu{sub 4}N){sub 7}SiW{sub 9}V{sub 3}O{sub 40} and (Bu{sub 4}N){sub 9}P{sub 2}W{sub 15}V{sub 3}O{sub 62} with an equimolar amount of CpTi{sup 3+} leads to the formation of the polyoxometalate-supported organometallic complexes [CpTi{lg_bullet}SiW{sub 9}V{sub 3}O{sub 40}]{sup 4{minus}}, 1, and [CpTi{lg_bullet}P{sub 2}W{sub 15}V{sub 3}O{sub 62}]{sup 6{minus}}, 2, respectively. These complexes were isolated as their Bu{sub 4}N{sup +} salts and subsequently characterized by a complete elemental analysis and {sup 31}P, {sup 183}W, {sup 51}V, and {sup 1}H NMR spectroscopy as well as FAB-MS,IR, and sedimentation-equilibrium molecular-weight measurements. For compound 1 additional data in the form of 2-D INADEQUATE {supmore » 183}W{sup 51V} NMR spectra were collected. Both 1 and 2 are homogeneous, regiospecifically supported CpTi{sup 3+} complexes of overall C{sub s} symmetry. Solution structures, derived from and in accord with the observed spectroscopic data, are proposed. The synthesis and initial solution spectroscopic characterization of the non-cyclopentadienyl, ClTi{sup 3+} complex, ClTi{lg_bullet}SiW{sub 9}V{sub 3}O{sub 40}{sup 4{minus}}, is also reported, a nominally highly coordinatively unsaturated Ti(IV) complex on route to more reactive catalyst precursors.« less