The transformation behavior of a U-16.4 at % Nb-5.6 at % Zr alloy

Karnowsky, M. M.; Rohde, R. W.

doi:10.1016/0022-3115(73)90064-0

Cited by 10 publications

(8 citation statements)

References 9 publications

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“…The addition of small amount of Nb significantly improves its corrosion resistance, allowing the production of 'stainless' U. Together with Zr, the addition of Nb to U also stabilizes the c phase at low temperature [6] for applications as metallic fuel [7,8]. Due to the low solubility of Nb in a and b phases of U, Nb is introduced to the hightemperature c phase [9,10].…”

Section: Introductionmentioning

confidence: 99%

Quantum mechanical calculations of uranium phases and niobium defects in γ-uranium

Xiang

Huang

Hsiung

2008

Journal of Nuclear Materials

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Section: Introductionmentioning

confidence: 99%

Quantum mechanical calculations of uranium phases and niobium defects in γ-uranium

Xiang

Huang

Hsiung

2008

Journal of Nuclear Materials

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“…U-7.5Nb-2.5Zr alloy also has this isothermal martensitic transformation for a¢¢ phase precipitation. [16][17][18][19][20] Thus, there are two types of martensitic transformations in the U-7.5Nb-2.5Zr alloy, (i) c fi c s being an athermic transformation resulting in a decrease in hardness and (ii) c s fi a¢¢ which is an isothermal transformation at low temperature associated with an increase in hardness. [31] This fact sheds some additional insight about the hardness behavior of the current studied alloy; hardness is a parameter which has an opposite behavior to the phenomenon of the a¢¢ phase precipitation (increase) and recovery (decrease).…”

Section: Resultsmentioning

confidence: 99%

“…[16] A considerable number of data can be found regarding phase transformation for this alloy. [17][18][19][20][21] A reasonable consensus exists on the identification of the phases present at high temperatures [range 673 K to 973 K (400°C to 700°C)], being a pearlite (a + c 3 ) formed by diffusion process. However, in the range of 373 K to 673 K (100°C to 400°C), divergences persist concerning the identification of metastable phases c o and a¢¢.…”

Section: Introductionmentioning

confidence: 99%

“…However, in the range of 373 K to 673 K (100°C to 400°C), divergences persist concerning the identification of metastable phases c o and a¢¢. [17][18][19][20][21] With respect to data available in the literature regarding the recrystallization in ''Mulberry'' alloy, a brief investigation was made by Peterson and Vandervoort. [21] In their work, no discussion was made about the hardness behavior, i.e., about the interacting phenomenon of phase precipitation and recrystallization.…”

Section: Introductionmentioning

confidence: 99%

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Hardness Response Surface for U-7.5Nb-2.5Zr Alloy: A Study of Recovery/Recrystallization and Phase Transformation Interactions

Lopes

Zimmermann

Restivo

et al. 2015

Metallurgical and Materials Transactions E

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Uranium alloys in monolithic form are an option for creating advanced nuclear fuels with very high uranium density, low isotopic enrichment, and high thermal conductivity. One aspect of the metallic fuel development is to demonstrate the retention of similar c-phase microstructure (c s) in the fuel alloy after fabrication and during the irradiation process. Unfortunately, there are few recent systematic studies in uranium alloys. Additionally, none of them are addressing the theme of recovery/recrystallization and phase transformations interactions that compose the basic metallurgical knowledge to manufacture nuclear fuel plates. This paper discusses this theme for U-7.5Nb-2.5Zr alloy employing a multivariate statistical technique, namely response surface methodology, to analyze the effect of the following process variables: degree of deformation, temperature, and time. Based on the results, in the range studied, the authors demonstrated that at low temperatures, the interaction between the recovery phenomenon and precipitation of metastable a¢¢ phase (isothermal martensitic shear transformation) shows a dependence with the degree of deformation, with prevalence of recovery for higher levels of this parameter. Interaction between a + c 3 phase nucleation and recrystallization is limited to a narrow temperature range [~848 K to 923 K (575°C to 650°C)] and during the first hour of annealing. Additionally, the series of phase transformations, c fi c s fi c o fi a¢¢, produced by shear was observed to be strongly dependent on crystallographic orientations and this fact could be used to enhance the retention of the metastable c s phase.

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“…For the particular case of U-Zr-Nb system, the introduction of elements zirconium and niobium can result in several structures such as (i) cubic γ s phase, obtained by quenching in water from the high temperature γ phase, (ii) tetragonal γ 0 produced by the aging of γ s , (iii) tetragonal α', phase transition of α and (iv) the monoclinic α'', transition of α precipitated by aging γ 0 [2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%