Effect of ternary alloying elements on the shape memory behavior of Ti–Ta alloys

Buenconsejo, Pio John S.; Kim, Hee-Young; Miyazaki, S.

doi:10.1016/j.actamat.2009.02.007

Cited by 120 publications

(72 citation statements)

References 26 publications

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“…17,18 Thermal and functional stability of Ti-Ta-X alloys have mostly been studied for short ageing times or a limited number of cycles. [8][9][10][11] Ti-27Ta-5Al was shown to be stable for up to 20 thermal cycles, where the maximum test temperature was about 250 ○ C. 10 Experiments conducted on Ti-30Ta and Ti-30Ta-3Al in related studies revealed that changes in test § …”

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confidence: 99%

“…16 In an attempt to hamper !-phase evolution, Buenconsejo et al added ternary alloying elements. [9][10][11] They showed that tin and aluminium are the most promising elements for stabilizing Ti-Ta-X alloys. 10,11 Other groups indicated that the Ti-Ta-Zr and Ti-Ta-Y systems may also represent potential HT SMA candidates.…”

mentioning

confidence: 99%

“…Based on the transformation temperatures of the SMA under consideration, i.e., start and finish temperatures for austenite and martensite (A s , A f , M s , M f ), actuation can be triggered at different temperatures. 6,7 For Ti-Ta-X (e.g., X ¼ Al) high-temperature (HT) SMAs, M s is adjusted to allow for actuation response under superimposed stresses in a temperature window between 150 ○ C and 300 ○ C. [8][9][10][11][12][13] Actuation strains for Ti-30 Ta have been shown to be highly dependent on the crystal orientation, providing exploitable transformation strains of up to 3.6% for the h011i orientation. 13 Ternary elements were shown to affect the absolute value of strains, but they do not alter the orientation dependence.…”

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Cyclic degradation of titanium–tantalum high-temperature shape memory alloys — the role of dislocation activity and chemical decomposition

Niendorf

Krooß

Somsen

et al. 2015

Funct. Mater. Lett.

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Titanium-tantalum shape memory alloys (SMAs) are promising candidates for actuator applications at elevated temperatures. They may even succeed in substituting ternary nickel-titanium high temperature SMAs, which are either extremely expensive or difficult to form. However, titanium-tantalum alloys show rapid functional and structural degradation under cyclic thermo-mechanical loading. The current work reveals that degradation is not only governed by the evolution of the !-phase. Dislocation processes and chemical decomposition of the matrix at grain boundaries also play a major role.Keywords: Microstructure; phase transformation; decomposition; training; !-phase.Shape memory alloys (SMAs) have been in the focus of intensive research for decades. 1-6 A fully reversible phase transformation from an austenitic high-temperature phase to a low-temperature martensitic phase can result in a substantial shape change. 1,2 Three types of shape memory effects are known: The one-way and the two-way shape memory effect and pseudoelasticity. 1,3,6 The first two effects can be exploited in actuator applications. Based on the transformation temperatures of the SMA under consideration, i.e., start and finish temperatures for austenite and martensite (A s , A f , M s , M f ), actuation can be triggered at different temperatures. 6,7 For Ti-Ta-X (e.g., X ¼ Al) high-temperature (HT) SMAs, M s is adjusted to allow for actuation response under superimposed stresses in a temperature window between 150 ○ C and 300 ○ C. 8-13 Actuation strains for Ti-30 Ta have been shown to be highly dependent on the crystal orientation, providing exploitable transformation strains of up to 3.6% for the h011i orientation. 13 Ternary elements were shown to affect the absolute value of strains, but they do not alter the orientation dependence. 14,15 A key issue for industrial applications of Ti-Ta-X HT SMAs is functional stability. Buenconsejo and co-workers showed that binary Ti-Ta alloys are prone to rapid degradation due to the evolution of the !-phase and a concomitant stabilization of the β-parent phase. 8,10,11 Similarly, the enrichment of β-stabilizers in the matrix as a result of !-phase formation was demonstrated for other β-Ti-alloys. 16 In an attempt to hamper !-phase evolution, Buenconsejo et al. added ternary alloying elements. [9][10][11] They showed that tin and aluminium are the most promising elements for stabilizing Ti-Ta-X alloys. 10,11 Other groups indicated that the Ti-Ta-Zr and Ti-Ta-Y systems may also represent potential HT SMA candidates. 17,18 Thermal and functional stability of Ti-Ta-X alloys have mostly been studied for short ageing times or a limited number of cycles. [8][9][10][11] Ti-27Ta-5Al was shown to be stable for up to 20 thermal cycles, where the maximum test temperature was about 250 ○ C. 10 Experiments conducted on Ti-30Ta and Ti-30Ta-3Al in related studies revealed that changes in test §

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Cyclic degradation of titanium–tantalum high-temperature shape memory alloys — the role of dislocation activity and chemical decomposition

Niendorf

Krooß

Somsen

et al. 2015

Funct. Mater. Lett.

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“…β 상에서 α'' 상으로의 변태온도는 첨가 원소 의 양에 따라 제어될 수 있다. 현재까지 많은 β 형 Ti기 합금에서 형상기억특성이 나 타난다고 보고 되어지고 있다; 예를 들어, Ti-Ta 기 합 금, [24][25] Ti-Mo 기 합금 6-11) 그리고 Ti-Nb 기 합금. 2.…”

Section: 서 론unclassified

Effect of Oxygen Content on Shape Memory Characteristics of Ti-18Nb-6Zr-XO (X = 0~1.5at%) Alloys

Park¹,

Ock²,

Oh³

et al. 2011

Korean. J. Mater. Res.

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The effect of oxygen on the shape memory characteristics in Ti-18Nb-6Zr-XO (X = 0-1.5 at%) biomedical alloys was investigated by tensile tests. The alloys were fabricated by an arc melting method at Ar atmosphere. The ingots were coldrolled to 0.45 mm with a reduction up to 95% in thickness. After severe cold-rolling, the plate was solution-treated at 1173 K for 1.8 ks. The fracture stress of the solution-treated specimens increased from 450 Mpa to 880 MPa with an increasing oxygen content up to 1.5%. The fracture stress increased by 287MPa with 1 at% increase of oxygen content. The critical stress for slip increased from 430 MPa to 695 MPa with an increasing oxygen content up to 1.5 at%. The maximum recovery strain of 4.1% was obtained in the Ti-18Nb-6Zr-0.5O (at%) alloy. The martensitic transformation temperature decreased by 140 K with a 1.0 at% increase in O content, which is lower than that of Ti-22Nb-(0-2.0)O (at%) by 20 K. This may have been caused by the effect of the addition of Zr. This study confirmed that addition of oxygen to the Ti-Nb-Zr alloy increases the critical stress for slip due to solid solution hardening without being detrimental to the maximum recovery strain.Key words shape memory effect, superelasticity, biomaterials, martenite, Ti based alloy. 서 론생체용

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“…In this paper, high temperature Ti-Ta shape memory alloys are digested based on the recent results of the present authors [16,20]. The following topics were described: 1) The transformation temperature, thermal stability and shape memory effect of Ti-Ta binary alloys, 2) The effect of different ternary alloying elements, including V, Cr, Fe, Zr, Mo, Hf, Al and Sn, on the shape memory behavior of Ti- Ta; 3) The effect of aging on the shape memory behavior in order to assess which elements are the most suitable to suppress the formation of phase in Ti-Ta base shape memory alloys; 4) Lastly the stability of high temperature shape memory effect during thermal cycling of selected ternary alloys.…”

Section: Introductionmentioning

confidence: 99%

Development of high temperature Ti-Ta shape memory alloys

Miyazaki

Kim

Buenconsejo

2009

ESOMAT 2009 - 8th European Symposium on Martensitic Transformations

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Abstract. Recent development of Ti-Ta and Ti-Ta-Al high temperature shape memory alloys was reviewed. The effect of Ta content on shape memory behavior of Ti-Ta alloys was first described. Shape memory effect was confirmed in Ti-(30-40)Ta alloys. The Ms formed during aging decreased with increasing Ta so that stable high temperature shape memory effect was confirmed for Ti-32Ta (Ms=440K) during thermal cycling between 173K and 513K. Secondly, the effect of ternary alloying elements (X = V, Cr, Fe, Zr, Hf, Mo, Sn, Al) on the shape memory behavior of Ti-30Ta-X alloys was described. Among the alloying elements, Sn and Al were effective to suppress the effect of aging on the shape For this reason the Ti-30Ta-1Al and Ti-30Ta-1Sn alloys exhibited stable high temperature shape memory effect during thermal cycling. It is suggested that Ti-Ta based alloys are attractive candidates for the development of novel high temperature shape memory alloys.

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Effect of ternary alloying elements on the shape memory behavior of Ti–Ta alloys

Cited by 120 publications

References 26 publications

Cyclic degradation of titanium–tantalum high-temperature shape memory alloys — the role of dislocation activity and chemical decomposition

Cyclic degradation of titanium–tantalum high-temperature shape memory alloys — the role of dislocation activity and chemical decomposition

Effect of Oxygen Content on Shape Memory Characteristics of Ti-18Nb-6Zr-XO (X = 0~1.5at%) Alloys

Development of high temperature Ti-Ta shape memory alloys

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