Strength differential effect in pseudoelastic NiTi shape memory alloys

Plietsch, R.; Ehrlich, K.

doi:10.1016/s1359-6454(96)00354-0

Cited by 68 publications

(41 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The mechanical fatigue tests were carried out only in tension. Under compression, different martensite variants are activated [4]. This had to be avoided, because different martensite variants in compression and tension make the microstructural analysis of damage more difficult.…”

Section: Thermomechanical Fatiguementioning

confidence: 99%

Effects of different thermomechanical treatments on fatigue of NiTi shape memory alloys

Wurzel

2001

J. Phys. IV France

View full text Add to dashboard Cite

Fully recrystallized NiTi sheets were deformed in four different temperature ranges: fully transformed martensite (T < M f ), transforming austenite (M s < T < Md), low temperature, stable austenite (M d < T < 1/3 T s ) and austenite at elevated temperatures (T > 1/3 T m ). The types and distributions of defects produced in these materials depend on the deformation temperature. The characteristic defect structures resulting from the low temperature deformation lead to different microstructures even after annealing. The thermomechanically treated as compared to the fully recrystallized NiTi alloys were subjected to thermal, mechanical and thermomechanical fatigue tests. Their microstructural origin was interpreted by TEM investigations. In conclusion it is proposed that a low ratio of pseudo-yield stress to true yield stress is responsible for good fatigue resistance. Regarding fatigue it is better to increase the yield stress by a small grain size than by a high dislocation density (work hardening).

show abstract

Section: Thermomechanical Fatiguementioning

confidence: 99%

Effects of different thermomechanical treatments on fatigue of NiTi shape memory alloys

Wurzel

2001

J. Phys. IV France

View full text Add to dashboard Cite

show abstract

“…The influence of the direction of a uniaxial normal stress (tension vs. compression) on superelastic stressinduced martensitic transformation has been observed on SMA single crystals as well as on textured or non-textured SMA polycrystals [6,[13][14]17,19,[24][25][26][27][28][29][30][31][32]. As an example, Figure 3 displays engineering stress-strain curves for a cyclic superelastic tension-compression test performed on one polycrystalline CuZnAl (Figure 3(a), [19]) and for two monotonic tension and compression tests performed at the same testing temperature on two identical NiTi polycrystalline plate samples (Figure 3(b), [14]).…”

Section: Comparison Between Compression and Tensionmentioning

confidence: 99%

“…This contributes to the asymmetric tension-compression deformation behaviour observed on isotropic as well as textured polycrystalline SMAs [32,43,47]. Several micro-macro models have been developed to investigate the role of both textures and single crystals behaviour on macroscopic anisotropy and tension-compression asymmetry in polycrystalline SMAs [31,[46][47]. Most of these models are based on the Phenomenological Theory of Martensite Crystallography (PTMC) and on self-consistent schemes [46][47].…”

Section: Role Of "Micro"-mechanisms At the Martensite-variant Level Amentioning

confidence: 99%

Stress state effect on mechanical behaviour of shape memory alloys : Experimental characterisation and modelling

Orgéas

Favier

2001

J. Phys. IV France

View full text Add to dashboard Cite

Abstract. As engineering components utilising the beneficial properties of shape memory alloys (SMA) become geometrically complex and as applications involve combinations of loading states, a full evaluation of the effects of stress state on stress-strain response of these materials becomes critical for the success of these applications. Such evaluation is required to establish reliable constitutive relationship to model the complex thermomechanical behaviour of SMAs. This paper is intended to present a non-exhaustive overview on studies and results dealing with experimental characterisation and modelling of the effects of stress state on mechanical behaviour of shape memory alloys. In that respect, our presentation is mainly focused on one hand on experimental results on superelastic and ferroelastic deformation of polycrystalline alloys and on the other hand on the modelling at the macroscopic level, yielding critical reorientation or transformation constitutive equations. INTRODUCTIONShape memory alloys (SMAs) are known to exhibit a range of novel thermomechanical properties due to thermoelastic martensitic transformations. The superelasticity is a quasi-elastic deformation far beyond the conventional elastic limit of the material when deformed at certain temperature above A p the finishing temperature of the reverse martensite-to-austenite transformation. This phenomenon is associated with stress-induced martensitic (SIM) transformation. If the temperature is lowered to below M p the finishing temperature of the forward austenite-to-martensite transformation, the deformation proceeds by martensite reorientation. Martensite may deformed by reorientation forth and back with alternating stresses in opposite directions. This deformation mode is known as the ferroelasticity, in recognition of its phenomenological similarity to ferromagnetism. The one-way shape memory effect is observed when a specimen deformed by martensite reorientation reverts to its original shape upon heating to above A f Numerous experimental works have been performed in the past three decades aiming at characterising the thermo-mechanical behaviour in order to provide experimental evidences for the establishment of constitutive models. These experimental studies have been devoted to both single-crystal and polycrystal specimens, mainly using Cu-based and NiTi SMAs. Most mechanical testing has been carried out in tension using wire specimens. Less work has been done to characterise properties under other stress states. As engineering components become geometrically complex and as applications involve combinations of loading states, it becomes important to characterise material properties in different stress states. This will allow the establishment of reliable constitutive equations to model the complex thermomechanical behaviour of SMAs.The present paper is intended to give a non-exhaustive overview on the studies and results dealing with experimental characterisation and modelling of the influence of stress state on mechanical behaviour of...

show abstract

“…Plietsch and Ehrlich (3) measured tension-compression stress-strain hysteresis loops for three types of SMA bar specimens. These specimens maintained (1) the austenitic phase and Vol.…”

Section: Introductionmentioning

confidence: 99%

Application of the Preisach Model to Tension-Compression Asymmetric Deformation Behavior of Martensitic Shape Memory Alloys

Akita

Ikeda

Ueda

2008

JMMP

View full text Add to dashboard Cite

The Preisach model is applied to the hysteresis of the energy required for reorientation of martensitic variants of shape memory alloys. To express tension-compression asymmetric behavior, three variants of the martensitic phase are considered-thermal-induced, tensile-stress-induced, and compressivestress-induced martensitic phases. Residual stresses due to unconformity at interfaces between grains are also considered in the required energy. Stress-strain hysteresis loops for a bar under tension-compression cyclic loading are simulated and they are compared with the available measured data. Results show that this model can effectively capture the asymmetric stress-strain deformation behavior for tension and compression and the difference between the stress-strain relationships in the first and second loops. This indicates that the proposed model can be used for explaining the deformation behavior of shape memory alloys and for the design of structural elements containing shape memory alloys.

show abstract

Strength differential effect in pseudoelastic NiTi shape memory alloys

Cited by 68 publications

References 3 publications

Effects of different thermomechanical treatments on fatigue of NiTi shape memory alloys

Effects of different thermomechanical treatments on fatigue of NiTi shape memory alloys

Stress state effect on mechanical behaviour of shape memory alloys : Experimental characterisation and modelling

Application of the Preisach Model to Tension-Compression Asymmetric Deformation Behavior of Martensitic Shape Memory Alloys

Contact Info

Product

Resources

About