Inheritance of the Elastic Field of a Dislocation Center for Martensite Nucleation by a Driving Wave Process

Кащенко, М. П.; Latypov, I. F.; Чащина, В. Г.

doi:10.1007/s11182-015-0465-1

Cited by 3 publications

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References 10 publications

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“…It is the IES that generates the wave process that overcomes the threshold deformation. As shown in [4][5][6], the CWP can inherit the deformation in the area of the IES. But, knowing the nucleation centers, this deformation can be calculated for known elastic moduli of the initial phase.…”

Section: Introductionmentioning

confidence: 99%

Nucleation centers for martensite with habitus {110} in the shape memory alloys

Кащенко

Чащина

2022

IOP Conf. Ser.: Mater. Sci. Eng.

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The dynamic theory of martensitic transformations (MT) considers the formation of habit planes of martensite crystals as a consequence of the propagation of a controlling wave process (CWP). The general ideology makes it possible, by comparing the observed habits with calculations of the elastic fields of defects (as a rule, dislocations), to identify nucleation centers. In a number of cases (In-Tl alloys, Ni50Mn50 alloys, Heusler alloys …) under MT in the shape memory alloys, {110} habits are observed (in the basis of the initial cubic phase), which often have a fine twin structure with twin boundaries of the same type. This highly symmetric structure is described by the CWP containing longitudinal waves (both relatively long-wavelength ℓ and short-wavelength s) propagating along the 4-order symmetry axes. In this paper, it is shown that such habits are associated with rectilinear segments of dislocation loops with directions Λ along <001> and Burgers vectors along <010> (or <110>) orthogonal to Λ, both for sliding and for prismatic loops. The tetragonality, the relative volume change during the MT, and the dependence of the start temperature M s on changes in the concentration of alloy components are also briefly discussed.

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Section: Introductionmentioning

confidence: 99%

Nucleation centers for martensite with habitus {110} in the shape memory alloys

Кащенко

Чащина

2022

IOP Conf. Ser.: Mater. Sci. Eng.

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Inheritance of the Strain Tensor by a Driving Wave Process in the Region of Martensite Nucleation on an Example of Fe–Ni Alloys

2016

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Crystal Dynamics of Forming ε-Martensite with Habit Planes {443}α in Titanium

Кащенко

Чащина

2017

Russ Phys J

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During martensitic transformations (MT), it is convenient to identify crystals specifying their morphological properties interrelated due to the action of a single control process. In the dynamic approach fully applicable to γ-α MT in iron alloys [1,2], it is most simple to describe them using habit planes (HP) without transition to finishing strains. One of the special features associated with description of morphology of BCC-HCP (α-ε) MT in titanium indicated, for example, in [3] is the presence of crystals of three groups. The first two groups with HP close to {334} α and {8 9 12} α are combined by the equality (or affinity) property of the smaller Miller indices as well as the orthogonality or approximate orthogonality of the plane {1 1 0} α , entering into the orientation relations (OR), to the habit plane. On the contrary, for the third group with HP close to {443} α , the equality (or affinity) of the largest Miller indices together with an acute angle between the plane {101} α , entering into the OR, and the habit plane takes place. Analogous HP are characteristic for lath and plate crystals (the letter can have internal twins).In theory [1,2], the fast (wave) growth was associated with the formation of an initial excited state (IES) in elastic fields of dislocation nucleation centers (DNC) in the vicinities of rectilinear dislocation loop segments. For example, segments with straight lines Λ║<110> α naturally arise during contact interaction of dislocations with sliding planes {110} α and {112} α . Calculations of an angular dependence of eigenvalues (for tension, ε 1 > 0, and for compression, ε 2 < 0) of the strain tensor ε for the IES and orientations of eigenvectors ξ 1,2 allow extreme regions to be detected where the interphase thresholds will be minimal and the IES will be most probable. The arising fluctuations engender wave beams with unit vectors n 1 = ξ 1 and n 2 = ξ 2 , and crystals with unit vectors N w perpendicular to HP are formed:In Eq. (1), ae is the ratio of the velocity moduli of quasi-longitudinal wave beams. FORMATION OF THE DNCWe believe that formation of the DNC is accompanied by energy decrease (in accordance with the Frank criterion). Then the simplest variant of interaction of two dislocations with sliding planes (112) α and (11 2

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Inheritance of the Elastic Field of a Dislocation Center for Martensite Nucleation by a Driving Wave Process

Cited by 3 publications

References 10 publications

Nucleation centers for martensite with habitus {110} in the shape memory alloys

Nucleation centers for martensite with habitus {110} in the shape memory alloys

Inheritance of the Strain Tensor by a Driving Wave Process in the Region of Martensite Nucleation on an Example of Fe–Ni Alloys

Crystal Dynamics of Forming ε-Martensite with Habit Planes {443}α in Titanium

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