Softening of nickel in the vicinity of its Curie point

Zaretsky, E.

doi:10.1063/1.2829790

Cited by 7 publications

(4 citation statements)

References 19 publications

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“…A similar drop of the dynamic yield stress caused by the presence of small amounts of foreign atoms was observed earlier for nickel of commercial purity. 40 As apparent from Fig. 3, the threewave structure in these tests is difficult to resolve; a weak kink in plastic shock wave caused by the c!e transition is recorded only after traversing 1.8 mm.…”

Section: B Evolution Of Elastic-plastic Waves At Normal and Elevatedmentioning

confidence: 90%

Yield stress, polymorphic transformation, and spall fracture of shock-loaded iron in various structural states and at various temperatures

Zaretsky

Kanel

2015

Journal of Applied Physics

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Delayed failure in a shock-loaded silicon carbideThe response of polycrystalline 99.5% pure iron was studied in a series of planar impact experiments, with samples of different thickness having an initial temperature that ranged between 300 and 1233 K. The free surface velocity histories of the shocked samples were recorded in the course of the experiments. Almost all recorded histories are characterized by a three-wave structure containing an elastic precursor P el and two plastic, P1 and P2, waves. It was found that at 300, 900, and 1039 K (some 5 K away from iron's Curie point), the decay of the P el wave with propagation distance is characterized by two different regimes; a fast one that corresponds to plastic strain rates above $10 5 s À1 and a slower one at lower strain rates. Since the shear stress at which the change-over takes place is very close to the Peierls stress of iron, we assume that above this stress the decay is governed by the phonon-damped over-barrier dislocation motion, while below it, the thermally activated generation and motion of the dislocation kinks is the governing mechanism. Based on the parameters of the P1 and P2 waves, both the initial and the maximum rates of the a ! e transformation in iron have been estimated. The results indicate that the approach to the Curie point is associated with a substantial, by 2-3 times, increase of the transformation rate. V C 2015 AIP Publishing LLC. [http://dx.

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Section: B Evolution Of Elastic-plastic Waves At Normal and Elevatedmentioning

confidence: 90%

Yield stress, polymorphic transformation, and spall fracture of shock-loaded iron in various structural states and at various temperatures

Zaretsky

Kanel

2015

Journal of Applied Physics

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“…Although it is known that behavior of both specific heat, 17 thermal expansion, 18,19 and elastic constants 20,21 of nickel near the Curie point is characteristic for the secondorder phase transitions, the temperature variations in the dynamic response of nickel in this temperature range was not studied until recently. 22 In the latter work it was found that in a close vicinity of its Curie point the nickel's Hugoniot elastic limit ͑HEL͒ has a sharp minimum, whose shape resembles that of the inverted spike of the specific heat. It should be noted that nickel samples used in Ref.…”

Section: Introductionmentioning

confidence: 96%

“…It should be noted that nickel samples used in Ref. 22 were of 99.5% purity and the temperature interval of the study was limited to the range from the ambient temperature to 700 K. Consequently, the objective of the present work is to compare the dynamic mechanical properties of such "impure" nickel with the properties of high purity nickel over the temperature interval from 150 to 1150 K. The latter temperature corresponds to the homologous T / T m Ϸ 0.7 temperature and is centered on approximately, T C Ϸ 630 K, the Curie point of nickel.…”

Section: Introductionmentioning

confidence: 99%

Impact response of nickel in the 150–1150 K temperature range

Zaretsky

2009

Journal of Applied Physics

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Samples of polycrystalline nickel of high (99.9945%) and commercial (99.5%) purity were studied in a series of planar impact experiments with initial, preshot, sample temperature ranging from 150 to 1150 K. The free surface velocity of the impacted sample was monitored by velocity interferometer. On the base of the recorded waveforms, the temperature dependences of the dynamic tensile (spall) and the dynamic yield strength of the two kinds of nickel were determined. Both strength parameters of the two types of nickel decline gradually with temperature. The trend, however, is broken by strong anomalies of the yield strength near the Curie point of nickel, 630 K. While the yield strength of the high purity nickel shows a twofold increase over a narrow interval in close vicinity of the magnetic transformation, the strength of commercially pure material experiences, in the same temperature interval, a threefold drop approaching the strength level characteristic for high-purity nickel. The possible mechanisms of the observed phenomena are discussed.

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“…Interrogation of the lattice during the shock was performed using the technique of wide-angle, in-situ diffraction [8,9] . Iron K-shell X-rays with a wavelength of 1.85 Å were created by direct irradiation of an iron foil positioned in close proximity to the shocked crystal sample (Fig.…”

Section: X-ray Diffractionmentioning

confidence: 99%

Ultrafast, In Situ Probing of Shocked Solids at the Mesoscale and Beyond: A New Paradigm for Materials Dynamics

Lorenzana¹,

Belak²,

Campbell³

et al. 2007

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Understanding material response under dynamic conditions and extreme pressures at the lattice level is important for being able to generate predictive models of material response. Despite many decades of study, material behavior is primarily inferred from bulk measurements on dynamically loaded samples or the microstructure from recovery experiments and not determined from lattice level measurements made in-situ at the relevant length scale of the governing physics. In the work described here, we report on progress made in advancing this frontier with research conducted under LDRD 04-ERD-071. Specifically, we present advances in, and applications of, dynamic x-ray diffraction, Extended X-ray Absorption Fine Structure and dynamic transmission electron microscopy.

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Softening of nickel in the vicinity of its Curie point

Cited by 7 publications

References 19 publications

Yield stress, polymorphic transformation, and spall fracture of shock-loaded iron in various structural states and at various temperatures

Yield stress, polymorphic transformation, and spall fracture of shock-loaded iron in various structural states and at various temperatures

Impact response of nickel in the 150–1150 K temperature range

Ultrafast, In Situ Probing of Shocked Solids at the Mesoscale and Beyond: A New Paradigm for Materials Dynamics

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