Thin film shape memory alloy microactuators

Krulevitch, Peter A; Lee, Abraham P.; Ramsey, P.B.; Trevino, J.; Hamilton, Julie; Northrup, M. Allen

doi:10.1109/84.546407

Cited by 497 publications

(264 citation statements)

References 36 publications

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“…Shape-memory materials have the largest energy output per unit volume per cycle of known actuator systems [36]. This fact, together with the enhanced rate of heat transfer in thin ®lms, makes these alloys ideal for microactuator, micropump and for microelectromechanical systems (MEMS) applications and this has motivated many experimental e orts (see, e.g.…”

Section: Introductionmentioning

confidence: 99%

The influence of texture on the shape-memory effect in polycrystals

1998

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AbstractÐA model is developed to show that texture is a crucial factor in determining the shape-memory e ect in polycrystals. In particular, it is established that texture is the reason why the strains recoverable in Ti±Ni are so much larger than those in Cu-based shape-memory alloys in rolled, extruded and drawn specimens. Further, it is shown that both these materials recover relatively small strains in sputter-deposited thin ®lms due to unfavorable texture. It is found that even the qualitative behavior of combined tension± torsion can critically depend on the texture. The results are in good agreement with experimental observations. Finally, textures are suggested for improved shape-memory e ect. #

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Section: Introductionmentioning

confidence: 99%

The influence of texture on the shape-memory effect in polycrystals

1998

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“…Both SME and SE are the phenomena related with thermoelastic martensitic transformation, and the shape recoverable stain depends on crystallographic difference between parent and martensite phases. It is known that SMAs exhibit the highest work per volume ( ¼ force £ strain/volume) of actuator materials [1]. It is also known that, although a large number of SMAs have been reported, only Ti -Ni SMA is practically and industrially used.…”

Section: Introductionmentioning

confidence: 99%

“…SE achieved at present exceeds 5% for a Ti -Nb -Al SMA. Third problem is a limited frequency in motion around 100 -200 Hz in comparison with 10 8 Hz for piezoelectric materials such as PZT [1]. The reason of low frequency is that the speed of motion is limited by heat transfer since heating and cooling cycles are required for the appearance of SME.…”

Section: Introductionmentioning

confidence: 99%

Material design and shape memory properties of smart composites composed of polymer and ferromagnetic shape memory alloy particles

Hosoda

Takeuchi

Inamura

et al. 2004

Science and Technology of Advanced Materials

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Ferromagnetic shape memory alloys (FSMAs) such as NiMnGa are expected to be new practical actuator materials with high driving frequency by magnetic field and large strain due to the shape memory effect (SME). However, the brittleness and poor workability of FSMAs, especially at a polycrystalline state, are serious problems and should be improved for a practical use. From this viewpoint a smart composite has been designed by a combination of a polymer matrix and FSMA particles (FSMAP), and a systematic investigation has been done for a NiMnGa-FSMAP/epoxy smart composite. This paper summarizes the design concept and some experimental results of the smart composite. It is pointed out that the single-crystal NiMnGa-FSMAP are easily made by mechanical crush due to the brittleness of FSMAs, and microstructural control is also possible by applying magnetic field during curing. Experimental study revealed that the NiMnGa-FSMAP/epoxy smart composites exhibit both tensile ductility and SME, and that shape memory properties become improved by decreasing particle size of FSMAP. It is concluded that the FSMAP/polymer smart composite has a large potential to be a new practical actuator material. q

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“…Thin films of shape-memory alloys have received attention as potential microactuators since the recognition that they possess the largest work per unit volume among possible actuator systems [7]. This is because the martensitic phase transformation, a solid-to-solid phase transformation responsible for the shape-memory effect, provides a direct link between the macroscopic deformation and microscopic changes in the crystalline unit cell.…”

Section: Introductionmentioning

confidence: 99%

Computational analysis of martensitic thin films using subdivision surfaces

Dondl

Shen

Bhattacharya

2007

Numerical Meth Engineering

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This paper studies numerically the deformation of thin films made of materials undergoing martensitic phase transformations by using subdivision surfaces. These thin films have received interest as potential microactuators, and specifically a tentlike configuration has recently been proposed. The study of such configurations requires adequate resolution of inhomogeneous in-plane stretch, out-of-plane deformation and transition regions across which the deformation gradient changes sharply. This paper demonstrates that subdivision surfaces provide an attractive tool in the numerical study of such configurations, and also provides insights into the tent-like deformations.

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Thin film shape memory alloy microactuators

Cited by 497 publications

References 36 publications

The influence of texture on the shape-memory effect in polycrystals

The influence of texture on the shape-memory effect in polycrystals

Material design and shape memory properties of smart composites composed of polymer and ferromagnetic shape memory alloy particles

Computational analysis of martensitic thin films using subdivision surfaces

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