Training effect in Fe-Mn-Si shape-memory alloys

Watanabe, Yoshihiko; Mori, Yotaro; Sato, Akira

doi:10.1007/bf00363341

Cited by 60 publications

(23 citation statements)

References 5 publications

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“…This is possibly due to exhaustion of the mobile Shockley partials, by which the recoverable strain is determined. Hence, the training effect some times plays a decisive role in the SME by generation of the Shockley partials 8) and actually used in application. 17) Related to the problem of the dislocation sources and their preservation, there are important factors controlling the SME properties such as intersection of one shear system with others, generation or stopping of the partials at grain boundaries and precipitates, retardation of the motion by Cottrell atmospheres and non-deformable obstacles, and so on.…”

Section: þmentioning

confidence: 99%

“…The degree of distribution in the internal stress may be inquired in the temperature dependence curve of the recovery strain. 8) In the above experiments, the annealing for the recovery was made by a creep type machine under a constant load and the recovery strain was measured after unloading. On the other hand, another common procedure in detecting the dimensional change is to utilize the elastic strain induced by the shape change associated with the $ " 0 transformation under a constraint imposed during heating and cooling.…”

Section: Recovery Strengthmentioning

confidence: 99%

“…0 martensitic transformation using the Fe-16 mass% Cr-14 mass% Ni stainless steel and one way type of the Schmidt law was confirmed for the h112if111g shear. 4,5) Starting with the base composition of Fe-(30-32) mass% Mn-6 mass% Si, 3,6,7) the investigations have been focused on anti-corrosion, 7) training effect, [7][8][9] internal friction, 10) cyclic-deformation 11,12) and strengthening. [13][14][15][16][17][18][19][20] The hybrid types of the Fe-Mn-Si based shape memory alloys (SMA) have been developed and some of the representative compositions are listed in Table 1.…”

Section: Introductionmentioning

confidence: 99%

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Mechanical Properties of Fe–Mn–Si Based SMA and the Application

2006

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The SME (shape memory effect) in an Fe-Mn-Si based SMA is governed by motion of Shockley partial dislocations which carry the fcc $ hcp phase transformations. The degree of SME is determined by preservation of the partial dislocations whereas the strength is determined by the internal stress opposing against the dislocation motion. The increase in the internal stress tends to induce dislocation reactions which ruin the preservation of the Shockley partials and hence to decrease the degree of SME. Nevertheless, usage of this SMA for construction of a large structural product has recently gained much attention even with sacrifice in the degree of SME. Upon application of this SMA in such a field, the optimum condition has to be searched both in the mechanical properties of the SMA itself and the type of the usage in the sense of deformation mode such as elongation, contraction, bending, twisting and so on. In this paper, the dislocation motion responsible for a good SME with high strength will be discussed on the ground of the basic knowledge of the dislocation generation, the motion and the reactions.

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Section: þmentioning

confidence: 99%

Section: Recovery Strengthmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Mechanical Properties of Fe–Mn–Si Based SMA and the Application

2006

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“…8,9) Fe-Mn-Si alloys appear to be commercially applicable owing to their inexpensiveness and excellent workability. With addition of Cr, it is possible to achieve a good corrosion resistance, which enhances commercial significance to this type of alloy.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Mechanical Properties of Fe-Mn-Si-Cr Shape Memory Fiber/Plaster Smart Composite

Watanabe¹,

Miyazaki²,

Okada

2002

Mater. Trans.

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This paper reports the fabrication method and mechanical properties of a shape memory alloy (SMA) fiber/plaster smart composite, which can be used in architectural and civil engineering applications. Fe-Mn-Si-Cr SMA fibers are subjected to pretensile strain at room temperature, and are embedded into plaster matrix. The Fe-Mn-Si-Cr SMA fiber/plaster composites are then heated up to 250 • C (above A s ) to generate a compressive residual stress in the matrix. Three-point bending test is performed for the mechanical property characterization. Fiber pull-out test is also conducted to evaluate the bonding strength at interface between SMA fiber and plaster matrix. Finite element analyses are carried out to have some further insights on the experimental results. It is found that the bending strength of the composites enhances with increasing level of pretensile strain. By using the inexpensive Fe-Mn-Si-Cr SMA fibers for the reinforcement of the SMA composite, one can obtain materials for practical engineering applications at low cost.

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“…[1] However, only 2 to 3 pct recovery strain is attained in ordinary polycrystalline-processed Fe-Mn-Si-based alloys without special treatment. [4][5][6] There are three kinds of special treatment-training, [7][8][9] thermomechanical, [5,10,11] and ausforming [12,13] -that improve the recovery strain of polycrystalline-processed Fe-Mn-Si SMAs to 4 to 5 pct. The preceding treatments not only increase the production cost, but also make it difficult to fabricate the components with complicated shape.…”

mentioning

confidence: 99%

A Novel Training-Free Processed Fe-Mn-Si-Cr-Ni Shape Memory Alloy Undergoing δ → γ Phase Transformation

Peng

Wang

Du³

et al. 2016

Metall Mater Trans A

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We not only suppress the formation of twin boundaries but also introduce a high density of stacking faults by taking advantage of d fi c phase transformation in a processed Fe-19.38Mn-5.29Si-8.98Cr-4.83Ni shape memory alloy. As a result, its shape memory effect is remarkably improved after heating at 1533 K (1260°C) (single-phase region of d ferrite) and air cooling due to d fi c phase transformation.Low-cost Fe-Mn-Si-based shape memory alloys (SMAs), possessing one-way shape memory effect, have attracted much attention for several decades as a possible alternative to the expensive Ti-Ni-based SMAs. [1][2][3][4][5][6] A large recovery strain of 9 pct has been reported in a single-crystalline Fe-30Mn-1Si alloy. [1] However, only 2 to 3 pct recovery strain is attained in ordinary polycrystalline-processed Fe-Mn-Si-based alloys without special treatment. [4][5][6] There are three kinds of special treatment-training, [7][8][9] thermomechanical, [5,10,11] and ausforming [12,13] -that improve the recovery strain of polycrystalline-processed Fe-Mn-Si SMAs to 4 to 5 pct. The preceding treatments not only increase the production cost, but also make it difficult to fabricate the components with complicated shape. Recently, we manufactured a novel training-free cast Fe-20.2Mn-5.6Si-8.9Cr-5.0Ni alloy by simple synthesis processing, consisting only of casting plus annealing, and made a breakthrough to attain a tensile recovery strain of 7.6 pct in this cast alloy. [14] Nevertheless, there are still shortcomings for cast alloys as compared with processed alloys, i.e., lower recovery stress and worse mechanical properties. Thus, we raise an issue regarding how to obtain training-free processed Fe-Mn-Si-based SMAs.Recently, we investigated the interaction between twin boundaries and stress-induced e martensite in Fe-MnSi-based SMAs and found that this interaction not only suppresses the stress-induced e martensitic transformation, but also severely distorts the twin interfaces. [14] As a result, a high density of twin boundaries results in a poor shape memory effect in processed Fe-Mn-Si-based SMAs, and a good shape memory effect could be obtained by inhibiting the formation of twin boundaries. Furthermore, Kajiwara indicated that a high density of stacking faults is beneficial to obtaining a good shape memory effect for processed Fe-Mn-Si-based SMAs. [5] Indeed, the previously mentioned special treatments that effectively improve the shape memory effect introduce the high density of stacking faults besides reducing the twin boundaries for processed Fe-Mn-Si-based SMAs. [5,8,[13][14][15] Here, we also achieve the purpose of both reducing the twin boundaries and introducing the high density of stacking faults using d fi c phase transformation in a Fe-19.38Mn-5.29Si-8.98Cr-4.83Ni alloy. Therefore, in the present article, a novel training-free processed Fe-Mn-Si-Cr-Ni alloy is developed based on d fi c phase transformation.The ingot of Fe-19.38Mn-5.29Si-8.98Cr-4.83Ni SMA was prepared by induction melting in an argon atmosphere. Thi...

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Training effect in Fe-Mn-Si shape-memory alloys

Cited by 60 publications

References 5 publications

Mechanical Properties of Fe–Mn–Si Based SMA and the Application

Mechanical Properties of Fe–Mn–Si Based SMA and the Application

Enhanced Mechanical Properties of Fe-Mn-Si-Cr Shape Memory Fiber/Plaster Smart Composite

A Novel Training-Free Processed Fe-Mn-Si-Cr-Ni Shape Memory Alloy Undergoing δ → γ Phase Transformation

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Training effect in Fe-Mn-Si shape-memory alloys

Cited by 60 publications

References 5 publications

Mechanical Properties of Fe&ndash;Mn&ndash;Si Based SMA and the Application

Mechanical Properties of Fe&ndash;Mn&ndash;Si Based SMA and the Application

Enhanced Mechanical Properties of Fe-Mn-Si-Cr Shape Memory Fiber/Plaster Smart Composite

A Novel Training-Free Processed Fe-Mn-Si-Cr-Ni Shape Memory Alloy Undergoing δ → γ Phase Transformation

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Mechanical Properties of Fe–Mn–Si Based SMA and the Application

Mechanical Properties of Fe–Mn–Si Based SMA and the Application