Martensitic Transformation in SUS304 Steels with the Same Ni Equivalent.

We present a theoretical study about the influence of magneto‐crystalline anisotropies on the static and dynamic magnetic properties of trilayers coupled via bilinear and biquadratic exchange fields for situations in which the systems are grown in unusual [hkl] low‐symmetry directions. We apply a realistic phenomenological model, with a total free magnetic energy that includes Zeeman interaction and magneto‐crystalline anisotropies as well as exchange energy terms. We consider parameters from the literature to illustrate our results for Fe/Cr/Fe systems. In particular, a total of six different magnetic scenarios for the [211] and [321] low‐symmetry growth orientations and three sets of exchange fields were analyzed, and the associated magnetization, magnetoresistance, and spin‐wave frequencies were calculated. Our results show that the combination of magneto‐crystalline symmetries and exchange fields leads to various interesting properties, including different values of the saturation field for the magnetization and magnetoresistance curves. Regarding the spin‐wave modes, we observed the presence of Goldstone modes, associated with second‐order phase transitions, resulting from the competition between the Zeeman and biquadratic energies.

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“…It is important to notice that whenever two of the Miller indices [ hkl ] are equal, we can choose a plane, for instance, [

italickk \overset{l}{true}

], in which the expression for the cubic anisotropy energy simplifies, resulting in terms of

{sin}^{4} θ

and

{cos}^{4} θ

(see Refs. ). A general expression for the cubic anisotropy energy for an arbitrary direction [ hkl ] is presented in Appendix A.…”

Section: Single‐layer Modelmentioning

confidence: 97%

Static and dynamic properties of [hkl] low‐symmetry trilayers

Celino

Costa

Bezerra

et al. 2016

Physica Status Solidi (b)

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Martensitic Transformations and Magnetic Properties of Model Alloys for Simulating Radiation Induced Segregation at Grain Boundaries in Stainless Steels

Kamada¹,

Zhang²,

Ara³

et al. 2004

J. Japan Inst. Metals

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We have investigated the magnetic properties of four model alloys (18Cr8Ni0.5Si, 16Cr10Ni1Si, 13Cr20Ni2Si, and 10Cr30Ni3Si) for simulating radiation induced segregation in SUS304 austenitic stainless steels. All alloys are paramagnetic at room temperature. With reduction of temperature, a structural transition was occurred for alloys with lower Ni content (18Cr8Ni0.5Si and 16Cr10Ni1Si), which produced ferromagnetic martensite. Alloys with higher Ni content (13Cr20Ni2Si, and 10Cr30Ni3Si) became ferromagnetic at low temperature without martensitic transformation. Different effects of stress on the structure and magnetism were found also. Martensitic transformations and magnetic properties of austenitic stainless steels de pend strongly on its chemical composition and can be classified by the value of Ni equivalent. This study suggests the possibility of applying magnetic methods to the nondestructive detection of radiation induced segregation.

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Correlation between Magnetic Hysteresis Properties and Vickers Hardness in Cladded Reactor Pressure Vessel Steel

Aihara

Kamada

Murakami

et al. 2017

J. Japan Inst. Metals and Materials

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We investigated the microstructure, magnetic hysteresis properties, and micro-Vickers hardness of nuclear reactor pressure vessel (RPV) steel cladded with austenitic stainless steel. Characterization of the crystalline structure by electron backscatter diffraction revealed the existence of a delta ferrite phase in the austenitic cladding, and the formation of coarse and fine grain microstructures in the heat affected zone (HAZ) of the RPV steel. The block specimen was cut into small pieces and magnetic hysteresis loops were measured with a vibrating sample magnetometer. Although the saturation magnetization of the RPV steel was constant, the coercivity in the HAZ region decreased gradually as a function of distance from the weld fusion boundary. A linear correlation was confirmed between the coercivity and hardness. This study demonstrates the feasibility of a magnetic evaluation of hardness and microstructures in RPV steel.

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Martensitic Transformation in SUS304 Steels with the Same Ni Equivalent.

Cited by 4 publications

References 2 publications

Static and dynamic properties of [hkl] low‐symmetry trilayers

Static and dynamic properties of [hkl] low‐symmetry trilayers

Martensitic Transformations and Magnetic Properties of Model Alloys for Simulating Radiation Induced Segregation at Grain Boundaries in Stainless Steels

Correlation between Magnetic Hysteresis Properties and Vickers Hardness in Cladded Reactor Pressure Vessel Steel

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