Effect of thermal cycling on as-quenched and aged nickel-rich Ni-Ti alloy

Stróż, Danuta; Bojarski, Z.; Ilczuk, J.; Lekston, Z.; Morawiec, H.

doi:10.1007/bf00543596

Cited by 38 publications

(15 citation statements)

References 11 publications

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“…These changes increase the temperature of austenite formation and reduce the formation temperature of martensite which is caused by dislocation and the interaction between the deposits. These are in agreement with Stroz et al (8) and Tadaki et al (9).…”

Section: Introductionsupporting

confidence: 93%

The Evaluation of the Fatigue and Thermocycling Effects on the Maximum Loading and Unloading Force of the CuNiTi Wire

Jelodar¹,

Shafiei²,

Rezaei³

2015

Iran J Ortho

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Background: In the oral environment orthodontic wires will be subjected to thermal fluctuations and repeated loading (fatigue). Objectives: The aim of this study is to evaluate the thermocycling and fatigue effect on the CuNiti wires. Materials and Methods: Samples of CuNiti wires, 0.014 round, were divided into four groups: 1, Fatigue loading; 2, Fatigue and thermocycling; 3, thermocycling; 4, control. The groups involved in fatigue loading by determined protocol (0.5 mm deflection, 1Hz frequency) also thermocycling performed by this method: bath time (90 seconds), transfer time (15 seconds) and temperature range: 5 -55C.after these procedure, fatigue and thermocycling effects on the maximum loading force (MLF) and maximum unloading force (MULF) assessed with a 3-point bending test. Results: In this study, the amounts of MLF in group 1 and 2 were significantly different with themselves and control group, but in the control group, the results were not significantly different with thermocycling group. Also the amounts of MLF in the group 3 were not different by the group 1 and 2. For the MULF, the results of group 1 and 2 were significantly different with the control and thermocycling group. Difference between fatigue and control groups for hysteresis loading (difference between MLF and MULF) variable was not significant while other two by two comparisons were significant. Conclusions: The fatigue loading increased MLF and MULF, but the effect of thermocycling was complicated on the MLF. Thermocycling also did not affect the MULF, but decreased hysteresis loading.

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Section: Introductionsupporting

confidence: 93%

The Evaluation of the Fatigue and Thermocycling Effects on the Maximum Loading and Unloading Force of the CuNiTi Wire

Jelodar¹,

Shafiei²,

Rezaei³

2015

Iran J Ortho

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“…IT is known that the shape memory characteristics of near-equiatomic Ti-Ni alloys are affected by the following treatments: annealing following cold working, [1][2][3][4] aging treatment in Ni-rich Ti-Ni alloys, [1,2,5] thermal cycling, [6][7][8][9] stress cycling, [7] and the addition of third elements. [10,11,12] Among these treatments, the aging treatment for Ni-rich Ti-Ni alloys is an effective method to improve shape memory and mechanical properties due to the formation of Ti 3 Ni 4 precipitates, which act as effective obstacles such as pinning points against the movement of dislocations, with the consequence that the critical stress for slip can be improved.…”

Section: Introductionmentioning

confidence: 99%

Comparison of shape memory characteristics of a Ti-50.9 At. Pct Ni alloy aged at 473 and 673 K

Kim

Miyazaki

2005

Metall Mater Trans A

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The effect of aging on transformation and deformation behavior, i.e., the transformation temperatures, shape memory behavior, and multistage martensitic and R-phase transformations, was investigated for a Ti-50.9 at. pct Ni alloy aged at a low temperature (Ͻ600 K) rarely used for practical applications and at a high temperature (Ͼ600 K) conventionally used for practical applications. It was found that there are many differences between aging at 473 and 673 K. The martensitic and R-phase transformation temperatures significantly varied depending on aging time and temperature. It is found that two-stage R-phase and multistage martensitic transformations appear in both the specimens aged at 473 and 673 K, respectively. The two-stage R-phase transformation appeared by aging at 473 K over 36 ks, while the multistage martensitic transformation (MSMT) appeared by aging at 673 K in the range of aging times between 1.2 and 36 ks. It is found that the critical stress for slip increases with increasing aging time in specimens aged at 473 K, while that of specimens aged at 673 K increases with increasing aging time until reaching a maximum, then it decreases with a further increase in aging time. It is also found that the critical stress for slip is superior for specimens aged at 473 K than that for specimens aged at 673 K. It was confirmed that dense and fine lenticular precipitates of about 10 nm in length were formed through aging, resulting in superior shape memory characteristics.

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“…This hypothesis is supported by the observation that ageing of a low-temperature-annealed sample, which was considered to contain a low vacancy concentration, did not induce the multiple-stage transformation behaviour in the alloy. Stroz et al [8] suggested that some ageing-induced specific arrangements of dislocations hinder the martensitic transformation in certain areas, causing the separation of the two martensitic transformations. Favier et al observed similar multiple-stage transformation behaviour in a Ti-49.5at%Ni alloy after an ageing treatment at 623 K [3].…”

Section: Introductionmentioning

confidence: 99%

Stability of ageing-induced multiple-stage transformation behaviour in a Ti-50.15%Ni alloy

Liu

Favier

2001

J. Phys. IV France

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Abstract.A fully annealed Ti-50.15%Ni alloy was found to develop a multiple-stage transformation behaviour after ageing at 623 K. The transformation behaviour corresponded to the R-phase transition and two separate martensitic transformations on cooling and two reverse transformations of the two martensites on heating. This study investigated the effects of overheating and thermal cycling on the stability of the multiple-stage transformation behaviour. It was found that overheating to above 723 K for a short time restored the single-stage transformation behaviour by eliminating the second martensitic transformation whilst merging the R-phase transition into the first martensitic transformation. Thermal cycling, on the other hand, was found to cause a degradation of the multiplestage transformation behaviour by eliminating the first martensitic transformation.

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Effect of thermal cycling on as-quenched and aged nickel-rich Ni-Ti alloy

Cited by 38 publications

References 11 publications

The Evaluation of the Fatigue and Thermocycling Effects on the Maximum Loading and Unloading Force of the CuNiTi Wire

The Evaluation of the Fatigue and Thermocycling Effects on the Maximum Loading and Unloading Force of the CuNiTi Wire

Comparison of shape memory characteristics of a Ti-50.9 At. Pct Ni alloy aged at 473 and 673 K

Stability of ageing-induced multiple-stage transformation behaviour in a Ti-50.15%Ni alloy

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