The Anelastic Effect due to Deformation Twins in Cu-Ge Alloy Crystals

Narita, Nobutaka; Umemoto, Toshiaki; Takamura, Jin-ichi; Yamamoto, Akitoshi

doi:10.2320/jinstmet1952.42.12_1190

Cited by 13 publications

(5 citation statements)

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“…They concluded that pre-existing twin boundaries become immobile in the presence of higher dislocation densities. They suggest that the ''unusual elastic behavior'' is probably related to the appearance/ disappearance of micro twins during loading/unloading, as previously observed by Narita et al [41] in Cu-Ge alloys. About 20 years after the work of Tadaki and Wayman [34], Zheng et al [24] and Zhao et al [25] were able to confirm by in situ transmission electron microscopy that indeed (011) microtwins appear/disappear during mechanical cycling.…”

Section: Introductionsupporting

confidence: 61%

Twinning-Induced Elasticity in NiTi Shape Memory Alloys

Birk

Biswas

Frenzel

et al. 2016

Shap. Mem. Superelasticity

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Pseudoelasticity (PE) in shape memory alloys relies on the formation of stress-induced martensite during loading and on the reverse transformation during unloading. PE yields reversible strains of up to 8 % and is applied in applications such as medical implants, flexible eye glass frames, damping elements, and others. Unfortunately, PE shows a strong temperature dependence and thus can only be exploited within a relatively narrow temperature window. The present work focuses on a related process, which we refer to as twinning-induced elasticity (TIE). It involves the growth and shrinkage of martensite variants which are stabilized by dislocations, which are introduced by appropriate cold work. TIE yields reversible strains of the order of 3 %. The TIE effect does not suffer from the strong temperature dependence of PE. The weak temperature dependence of mechanical TIE properties makes TIE attractive for applications where temperature fluctuations are large. In the present work, we study the TIE effect focusing on Ni 50 Ti 50 shape memory alloy wires. The degree of plastic pre-deformation of the initial material represents a key parameter of the ingot metallurgy processing route. It governs the exploitable recoverable strain, the apparent Young's modulus, and the widths of the mechanical hysteresis. Dynamic mechanical analysis is used to study the effects of pre-deformation on elementary microstructural processes which govern TIE.

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Section: Introductionsupporting

confidence: 61%

Twinning-Induced Elasticity in NiTi Shape Memory Alloys

Birk

Biswas

Frenzel

et al. 2016

Shap. Mem. Superelasticity

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“…Next, the driving force for the twinning pseudoelasticity is quantitatively discussed by modifying the theory proposed by Green et al 7) and Narita et al 12) When the twinning pseudoelasticity appears in Fe 3 Ga single crystals, the following equations hold true during loading and unloading. 7,12) …”

Section: Discussionmentioning

confidence: 99%

Temperature Dependence of Twinning Pseudoelasticity in Fe<SUB>3</SUB>Ga Single Crystals

2010

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Temperature dependence of twinning pseudoelasticity in D0 3 -ordered Fe 3 Ga single crystals was examined. In the crystals annealed in the D0 3 single-phase region, 2:2 T -type pseudo-twins were frequently introduced during loading at and below room temperature. Since the pseudotwins had a high energy compared with a perfect twin, the untwinning took place during unloading to decrease their energy resulting in the twinning pseudoelasticity. Moreover, the twinning pseudoelasticity became more dominant with decreasing temperature, in contrast to that based on dislocation motion. In particular, high strain recovery during unloading was

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“…For single crystals and single-phase materials, such staging was discovered in early studies (see reviews [37,38]). Then, it was confirmed for polycrystals of pure metals with different syngonies [39][40][41], as well as for solid solutions and intermetallic compounds of FCC metals [42][43][44]. Data on the stages of plastic stress-strain curves for various metallic materials were summarized in [45][46][47][48].…”

Section: The 'σ-ε' and 'θ-ε' Dependencesmentioning

confidence: 99%

“…In this case, the number of active twinning systems could determine staging of the flow curves and the strain hardening coefficient (θ). It is known [42,43] that if twinning develops due to a deformation of the slip mechanism, then competition between cross slip and twinning could be observed. After slip, the development of twinning in one system has to suppress the cross-slip processes and causes an increase in the plasticity of crystals, i.e., the twinning-induced plasticity (TWIP) effect has to be observed.…”

Section: The 'σ-ε' and 'θ-ε' Dependencesmentioning

confidence: 99%

Relationship of Internal Stress Fields with Self-Organization Processes in Hadfield Steel under Tensile Load

Попова

Slobodyan

Klopotov

et al. 2023

Metals

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The effect of tensile strains on the microstructure of Hadfield steel was studied by transmission electron microscopy (TEM). Stages of the obtained stress–strain curves were observed, and correlated well with the evolution of the dislocation substructure. Based on an analysis of TEM images, quantitative parameters were determined, such as the material volume fractions, in which slip and twinning occurred, as well as twinning, which developed in one, two and three systems. Some transformation mechanisms were reported that caused great hardening of Hadfield steel. In particular, a complex defect substructure formed in a self-organized manner due to the formation of cells, the dislocations retarded by their walls, as well as the deceleration of dislocations on twins and, vice versa, of twins on dislocations. These factors affected both the average and excess local density of dislocations. Additionally, they resulted in elastic stress fields, which manifested themselves in the curvature–torsion gradient of the crystal lattice. A high level of stresses caused by solid-solution strengthening prevented the relaxation of elastic ones, contributing to the strain hardening of the Hadfield steel.

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The Anelastic Effect due to Deformation Twins in Cu-Ge Alloy Crystals

Cited by 13 publications

References 0 publications

Twinning-Induced Elasticity in NiTi Shape Memory Alloys

Twinning-Induced Elasticity in NiTi Shape Memory Alloys

Temperature Dependence of Twinning Pseudoelasticity in Fe<SUB>3</SUB>Ga Single Crystals

Relationship of Internal Stress Fields with Self-Organization Processes in Hadfield Steel under Tensile Load

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