Creep properties of Zr-1wt.%Nb alloy

Thorpe, W.R.; Smith, Ian

doi:10.1016/0022-3115(78)90001-6

Cited by 29 publications

(8 citation statements)

References 18 publications

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“…Accordingly, the threshold stress for HANA-4 calculated using Eq. [15] is about 4 MPa in all the test temperatures employed in this study if the very small difference in the stress values arising due to the variance in temperatures is neglected. However, as seen from the creep data of HANA-4 at 773 K (500°C), the creep rates in regime II transit into regime I, where diffusional creep mechanism was suggested to be operative, at a stress of 19 MPa.…”

Section: Transition From Regime II To Regime Iiimentioning

confidence: 99%

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Coble, Orowan Strengthening, and Dislocation Climb Mechanisms in a Nb-Modified Zircaloy Cladding

Kombaiah

Murty

2015

Metall Mater Trans A

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BOOPATHY KOMBAIAH and KORUKONDA LINGA MURTYBiaxial creep tests on HANA-4 tubes, Nb-added Zircaloy-4 were conducted using internal pressurization of closed-end tubes to investigate the rate-controlling mechanisms over a range of hoop stresses, 8:38 Â 10 À5 E À 2:87 Â 10 À3 E, at three different temperatures 673 K, 723 K, and 773 K (400°C, 450°C, and 500°C). The mechanistic creep parameters such as stress exponent (n) and activation energy (Q C ) were then determined from steady-state creep rates. Based on the variance in stress exponent with respect to the applied stress, three regimes have been identified: a stress exponent close to 1 at low stresses that increased to 3 at the intermediate stresses, which became 4.5 at high stresses. An activation energy value of 226 kJ/mol was evaluated for the n = 3 and n = 4.5 regimes, which lies close to the activation energy for self-diffusion (Q L ) in a-Zr alloys. Further, TEM analyses of crept microstructures and comparison of experimental results with standard models were undertaken to find out the rate-controlling mechanisms. Coble creep, climbing of dislocations to bypass b-Nb precipitates, and dynamic recovery by edge dislocation climb are proposed as the rate-controlling mechanisms in the n = 1, n = 3, and n = 4.5 regimes of HANA-4, respectively.

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Section: Transition From Regime II To Regime Iiimentioning

confidence: 99%

“…This relation given in Eq. [15] could be applied to HANA-4 since general climb of dislocations has been suggested to occur in regime II. Accordingly, the threshold stress for HANA-4 calculated using Eq.…”

Section: Transition From Regime II To Regime Iiimentioning

confidence: 99%

Coble, Orowan Strengthening, and Dislocation Climb Mechanisms in a Nb-Modified Zircaloy Cladding

Kombaiah

Murty

2015

Metall Mater Trans A

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“…[23] The increase of Nb from 1 to 2.5 pct clearly reveals that the grain growth is restricted and that the volume fraction of Zr 2 Fe in Zr-2.5 pct Nb was much smaller than that of Zr(FeCr) 2 in Zr-1 pct Nb, even though the same amount of Fe was present in both the alloys. As Zr-2.5 pct Nb contains a higher volume fraction of ␤ phase reflections for all the alloys are shown in Table III.…”

Section: Reflections and Compound Fault Parameter Valuesmentioning

confidence: 94%

Microstructural studies on lattice imperfections in deformed zirconium-base alloys by x-ray diffraction

Mukherjee

Barat

Bandyopadhyay

et al. 2000

Metall Mater Trans A

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X-ray diffraction intensity data from three compositions of zirconium-base alloys, viz. ZIRCALOY-2, ZIRLO, and Zr-25 pct Nb, having extensive application in nuclear industry were recorded using a PHILIPS PW 1730 X-ray diffractometer. Detailed studies using the recorded diffractometer data, keeping in view the recent trends in the powder diffraction analysis, were carried out with a view to evaluating the microstructural paramaters, including domain size, microstrain, faulting probability, and dislocation density. While faulting appears to be absent in all alloys, the average domain size and root-mean-square (rms) strain appear to be smaller compared to pure zirconium. However, both of these parameters, i.e., average domain size and rms strain tend to increase with the addition of Nb, as in ZIRLO, but display a diminishing trend with higher content of Nb, as is evident in the Zr-2.5 pct Nb alloy.

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“…In the low temperature range of 300∼400 • C, several deformation mechanisms such as climbcontrolled dislocation creep, recovery creep, and grain boundary sliding (GBS) have been suggested. At temperatures higher than 400 • C, Haper-Dorn creep has been reported as well as diffusion creep such as Nabarro-Herring creep and Coble creep [1][2][3][4][5][6] . But some authors argued Coble creep as a plausible mechanism even in the low temperature range, especially at the low stress range [7] .…”

Section: Stress Exponent Analysismentioning

confidence: 99%

Creep Behavior of Zr-1.5Nb-0.4Sn-0.1Fe-0.1Cu Alloy

Kim

et al. 2008

Acta Mech. Solida Sin.

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Creep behavior of the Zr-1.5Nb-0.4Sn-0.1Fe-0.1Cu alloy sheet is investigated from 300 • C to 400 • C in the stress range from 50 MPa to 180 MPa along the rolling direction. The measured strain rates range from 8.8 × 10 −10 s −1 to 4.7 × 10 −7 s −1 . The activation energies are estimated to assess the creep deformation mechanisms in this alloy. The strain rate is slightly different at low stress, while it shows a distinct difference at high stresses. Stress exponents of this alloy increase with increasing applied stress at all testing temperatures. It is concluded that the creep deformation of the Zr-1.5Nb-0.4Sn-0.1Fe-0.1Cu alloy is controlled by the diffusion creep at low stress region and by the climbing of dislocations at high stress region.

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Creep properties of Zr-1wt.%Nb alloy

Cited by 29 publications

References 18 publications

Coble, Orowan Strengthening, and Dislocation Climb Mechanisms in a Nb-Modified Zircaloy Cladding

Coble, Orowan Strengthening, and Dislocation Climb Mechanisms in a Nb-Modified Zircaloy Cladding

Microstructural studies on lattice imperfections in deformed zirconium-base alloys by x-ray diffraction

Creep Behavior of Zr-1.5Nb-0.4Sn-0.1Fe-0.1Cu Alloy

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