Effect of pre-deformation on the precipitation process and magnetic properties of Fe–Cu model alloys

Kamada, Y.; Takahashi, Seiki; Kikuchi, Hiroaki; Kobayashi, Satoru; Ara, K.; Echigoya, J.; Tozawa, Yusuke; Watanabe, Kenta

doi:10.1007/s10853-008-3182-0

Cited by 36 publications

(9 citation statements)

References 13 publications

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“…30͒ and for 1.3 wt % Cu, 12 and very close to that reported for 1.0 wt % Cu. 32 The observed effect of prestrain on the hardness during aging is consistent with that observed by Deschamps and co-workers. Figure 3 shows the S and W parameters measured for the as-quenched samples, the 8% deformed samples, and the fractured samples.…”

Section: A Aging Curvessupporting

confidence: 90%

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Thermally activated precipitation at deformation-induced defects in Fe-Cu and Fe-Cu-B-N alloys studied by positron annihilation spectroscopy

Dijk

Schüt

et al. 2010

Phys. Rev. B

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We have investigated the influence of deformation-induced defects on the isothermal precipitation at 550°C in as-quenched ͑solute-supersaturated͒ and annealed ͑solute-depleted͒ Fe-Cu and Fe-Cu-B-N alloys by positron annihilation spectroscopy and hardness tests. Using the coincidence Doppler broadening technique, the evolution of local environment at the positron annihilation sites ͑open-volume defects, Cu precipitates, and matrix͒ was monitored as a function of the aging time. For all samples, plastic deformation causes a pronounced change in S and W parameters signaling the formation of open-volume defects. For the as-quenched samples, aging results in a sharp decrease in the amount of open-volume defects combined with the rise of a strong copper signature, which can be attributed to preferential copper precipitation at the open-volume defects introduced by plastic deformation. In contrast, the open-volume defects of the annealed samples can only be reduced partially. Both the hardness tests and the positron annihilation spectroscopy indicate that the addition of B and N to the Fe-Cu alloy causes a significant acceleration of the precipitation in the as-quenched alloys.

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Section: A Aging Curvessupporting

confidence: 90%

“…12,[30][31][32] Both the peak hardness and the aging time to peak are in between those reported for 0.8 wt % Cu ͑Ref. 30͒ and for 1.3 wt % Cu, 12 and very close to that reported for 1.0 wt % Cu.…”

Section: A Aging Curvessupporting

confidence: 79%

Thermally activated precipitation at deformation-induced defects in Fe-Cu and Fe-Cu-B-N alloys studied by positron annihilation spectroscopy

Dijk

Schüt

et al. 2010

Phys. Rev. B

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“…Ghosh et al [11] have found that the 50% pre-strain prior to aging could trigger the precipitation by decreasing the activation energy values for Cu precipitation from 182 to 126 kJ/mol. Kamada et al have conducted a series of experiments to simulate the irradiation embrittlement of nuclear RPV steels [12]. The Fe-1 weight percent (wt.%) Cu alloys with and without pre-deformation in the solid-state solution were thermally aged at 773 K (500°C) for various times.…”

Section: Introductionmentioning

confidence: 99%

Influence of thermo-mechanical embrittlement processing on microstructure and mechanical behavior of a pressure vessel steel

Bai

Liaw

2016

Materials & Design

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“…17 In Fe-Cu, Cu precipitates first form as BCC, and their pinning effect on domain walls increase with their size until a diameter of ∼4-6 nm, where BCC-CRP change to FCC-CRP, which have a lesser pinning effect than the BCC-CRP. 15,18,19 From the size distributions determined, all of the precipitates were FCC, and the averages are shown in Table I, size distributions being larger for longer aging times (not shown). The major loop coercivity (H cm ) initially increases then decreases with aging time which is consistent with the behavior of microhardness (Table I).…”

Section: Resultsmentioning

confidence: 99%

“…19,24 The initial decrease in MBN RMS is probably caused by the formation of CRPs which decreases the mean free path for magnetic domain movement leading to a general decrease of MBN amplitude. 15,[18][19][20][21]24 However, as the heat treatment continues, the CRPs increase in size and the number density of CRP decreases (Table I), so subsequent decrease in MBN RMS with aging cannot be due to number of precipitates.…”

Section: /Mmentioning

confidence: 99%

Effects of aging time and temperature of Fe-1wt.%Cu on magnetic Barkhausen noise and FORC

et al. 2016

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Investigation of effects of long-term thermal aging on magnetization process in low-alloy pressure vessel steels using first-order-reversal-curves AIP Advances 7, 056002 (2017); 10.1063/1.4973605Effect of defects, magnetocrystalline anisotropy, and shape anisotropy on magnetic structure of iron thin films by magnetic force microscopy AIP Advances 7, 056806 (2017) Magnetic Barkhausen noise (MBN), hysteresis measurements, first order reversal curves (FORC), Vickers microhardness, and Transmission Electron Microscopy (TEM) analyses were performed on Fe-1wt.%Cu (Fe-Cu) samples isothermally aged at 700 • C for 0.5 -25 hours to obtain samples with different sized Cu precipitates and dislocation structures. Fe-Cu is used to simulate the thermal and irradiation-induced defects in copper-containing nuclear reactor materials such as cooling system pipes and pressure vessel materials. The sample series showed an initial increase followed by a decrease in hardness and coercivity with aging time, which is explained by Cu precipitates formation and growth as observed by TEM measurements. Further, the MBN envelope showed a continuous decrease in its magnitude and the appearance of a second peak with aging. Also, FORC diagrams showed multiple peaks whose intensity and location changed for different aging time. The changes in FORC diagrams are attributed to combined changes of the magnetic behavior due to Cu precipitate characteristics and dislocation structure. A second series of samples aged at 850 • C, which is above the solid solution temperature of Fe-Cu, was studied to isolate the effects of dislocations. These samples showed a continuous decrease in MBN amplitude with aging time although the coercivity and hardness did not change significantly. The decrease of MBN amplitude and the appearance of the second MBN envelope peak are attributed to the changes in dislocation density and structure. This study shows that the effect of dislocations on MBN and FORC of Fe-Cu materials can vary significantly and should be considered in interpreting magnetic signatures. C 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.

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Effect of pre-deformation on the precipitation process and magnetic properties of Fe–Cu model alloys

Cited by 36 publications

References 13 publications

Thermally activated precipitation at deformation-induced defects in Fe-Cu and Fe-Cu-B-N alloys studied by positron annihilation spectroscopy

Thermally activated precipitation at deformation-induced defects in Fe-Cu and Fe-Cu-B-N alloys studied by positron annihilation spectroscopy

Influence of thermo-mechanical embrittlement processing on microstructure and mechanical behavior of a pressure vessel steel

Effects of aging time and temperature of Fe-1wt.%Cu on magnetic Barkhausen noise and FORC

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