Functional and structural fatigue of titanium tantalum high temperature shape memory alloys (HT SMAs)

Niendorf, Т.; Krooß, P.; Batyrsina, E.; Paulsen, Alexander; Motemani, Yahya; Ludwig, Alfred; Buenconsejo, Pio John S.; Frenzel, Jan; Eggeler, Gunther; Maier, Hans Jürgen

doi:10.1016/j.msea.2014.10.038

Cited by 38 publications

(32 citation statements)

References 28 publications

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“…4) that corresponds to the minima in volume change and hysteresis (Fig. 3), and hardness becomes close in value to TiNi for Ti 16.667 Zr 16.667 Hf 16.667 Co 10 Ni 25 Cu 15 high-entropy intermetallic. In the case of TiNi, during the hardness measurements, the formation of stress-induced martensite and reorientation of existing one take place under the indenter due to high mobility of the Fig.…”

Section: Resultsmentioning

confidence: 79%

“…Yet, even if the TiNi-or Cu-based shape memory alloys show all signs of thermoelastic behaviour, certain degree of the plastic relaxation (creation and movement of full dislocations) of the internal stresses at austenite/martensite interface might not be avoided. Subsequently, thermal cycling effects (or thermal fatigue) appear [7,8], as well as the degradation of shape memory effect [9] and mechanical [8], functional or structural [10] fatigue phenomena. Obviously, all these irreversible processes intensify at elevated temperatures, as it might be seen, for example, in the case of Ti 50 Pd 40 Ni 10 high-temperature shape memory alloy [11] because of the irreversible plastic flow in a first place or structural fatigue (xphase formation), likewise it can be seen in Ti-Ta during diffusive phase transformation [10].…”

Section: Introductionmentioning

confidence: 99%

“…Subsequently, thermal cycling effects (or thermal fatigue) appear [7,8], as well as the degradation of shape memory effect [9] and mechanical [8], functional or structural [10] fatigue phenomena. Obviously, all these irreversible processes intensify at elevated temperatures, as it might be seen, for example, in the case of Ti 50 Pd 40 Ni 10 high-temperature shape memory alloy [11] because of the irreversible plastic flow in a first place or structural fatigue (xphase formation), likewise it can be seen in Ti-Ta during diffusive phase transformation [10]. All of them become the obstacles for successful application of high-temperature shape memory alloys (HTSMAs) [12,13].…”

Section: Introductionmentioning

confidence: 99%

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Directions for High-Temperature Shape Memory Alloys’ Improvement: Straight Way to High-Entropy Materials?

Firstov

Kosorukova

Koval

et al. 2015

Shap. Mem. Superelasticity

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Nowadays, all thermo-mechanical effects, associated with the martensitic structural phase transitions, are still in the focus of scientists and engineers, especially once these phenomena are taking place at elevated temperatures. The list of the materials, undergoing high-temperature martensitic transformation, is constantly widening. Still, industrial application of these materials, called hightemperature shape memory alloys, is far enough due to the lack of understanding of the peculiarities of the high-temperature martensitic transformation and shape memory effect. The present work attempts to show how the development of the proper directions for high-temperature shape memory alloys' improvement might lead to the creation of essentially new functional materials.Keywords Martensitic phase transformation Á Crystal and electronic structure Á Shape memory behaviour Á High temperature shape memory alloys Á High entropy alloys

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Section: Resultsmentioning

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Directions for High-Temperature Shape Memory Alloys’ Improvement: Straight Way to High-Entropy Materials?

Firstov

Kosorukova

Koval

et al. 2015

Shap. Mem. Superelasticity

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“…Shape memory alloys (SMAs) have been in focus of intensive research for decades [1][2][3][4][5][6][7].…”

Section: ____________________________________________________________mentioning

confidence: 99%

“…in pseudoelastic damping and actuation. Numerous alloys have been characterized, and Ni-Ti alloys have been the main focus of SMA activities [1][2][3]5,8]. As Ni-Ti inherently is limited in its applicability due to relatively high processing costs and transformation temperatures below 100 °C, new alloys have been proposed in recent years aiming at overcoming these limitations [3,[4][5][6][7][9][10][11].…”

Section: ____________________________________________________________mentioning

confidence: 99%

Martensite stabilization in shape memory alloys – Experimental evidence for short-range ordering

et al. 2015

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Microstructure, Shape Memory Effect and Functional Stability of Ti₆₇Ta₃₃ Thin Films

et al. 2015

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Ti-Ta based alloys are an interesting class of high-temperature shape memory materials. When fabricated as thin films, they can be used as high-temperature micro-actuators with operation temperatures exceeding 100°C. In this study, microstructure, shape memory effect and thermal cycling stability of room-temperature sputter deposited Ti 67 Ta 33 thin films are investigated. A disordered a 00 martensite (orthorhombic) phase is formed in the as-deposited Ti 67 Ta 33 films. The films show a columnar morphology with the columns being oriented perpendicular to the substrate surface. They are approximately 200 nm in width. XRD texture analysis reveals a martensite fiber texture with {120} and {102} fiber axes. The XRD results are confirmed by TEM analysis, which also shows columnar grains with long axes perpendicular to the {120} and {102} planes of a 00 martensite. The shape memory effect is analyzed in the temperature range of -10 to 240°C using the cantilever deflection method, with special emphasis placed on cyclic stability. Ti 67 Ta 33 thin films undergo a forward martensitic transformation at M s % 165°C, with a stress relaxation of approximately 33 MPa during the transformation. The actuation response of the film actuators degrades significantly during thermal cycling. TEM analysis shows that this degradation is related to the formation of nanoscale v precipitates (5-13 nm) which form above the austenite finish temperature. These precipitates suppress the martensitic transformation, as they act as obstacles for the growth of martensite variants.

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Functional and structural fatigue of titanium tantalum high temperature shape memory alloys (HT SMAs)

Cited by 38 publications

References 28 publications

Directions for High-Temperature Shape Memory Alloys’ Improvement: Straight Way to High-Entropy Materials?

Directions for High-Temperature Shape Memory Alloys’ Improvement: Straight Way to High-Entropy Materials?

Martensite stabilization in shape memory alloys – Experimental evidence for short-range ordering

Microstructure, Shape Memory Effect and Functional Stability of Ti₆₇Ta₃₃ Thin Films

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Functional and structural fatigue of titanium tantalum high temperature shape memory alloys (HT SMAs)

Cited by 38 publications

References 28 publications

Directions for High-Temperature Shape Memory Alloys’ Improvement: Straight Way to High-Entropy Materials?

Directions for High-Temperature Shape Memory Alloys’ Improvement: Straight Way to High-Entropy Materials?

Martensite stabilization in shape memory alloys – Experimental evidence for short-range ordering

Microstructure, Shape Memory Effect and Functional Stability of Ti67Ta33 Thin Films

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Microstructure, Shape Memory Effect and Functional Stability of Ti₆₇Ta₃₃ Thin Films