Oriented nickel-titanium shape memory alloy films prepared by annealing during deposition

Gisser, Kathleen R. C.; Busch, John D.; Johnson, A. David; Ellis, Arthur B.

doi:10.1063/1.108434

Cited by 76 publications

(31 citation statements)

References 3 publications

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“…Martensitic thin films have recently attracted much interest because of their potential for application as microactuators [27,28,39,33,18,17]. Martensitic materials undergo a diffusionless phase transformation during which there is a sudden change in the crystal structure at a certain temperature.…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous Thin Films of Martensitic Materials

Shu¹

2000

Archive for Rational Mechanics and Analysis

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We study the effective behavior of heterogeneous thin films with three competing length scales: the film thickness and the length scales of heterogeneity and material microstructure. We start with three-dimensional nonhomogeneous nonlinear elasticity enhanced with an interfacial energy of the van der Waals type, and derive the effective energy density as all length scales tend to zero with given limiting ratios. We do not require any a priori selection of asymptotic expansion or ansatz in deriving our results. Depending on the dominating length scale, the effective energy density can be identified by three procedures: averaging, homogenization and thin-film limit. We apply our theory to martensitic materials with multi-well energy density and use a model example to show that the "shape-memory behavior" can crucially depend on the ratios of these length scales. We comment on the effective conductivity of linear composites, and also on multilayers made of shape-memory and elastic materials.

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Section: Introductionmentioning

confidence: 99%

Heterogeneous Thin Films of Martensitic Materials

Shu¹

2000

Archive for Rational Mechanics and Analysis

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“…Note that they are larger for flat grains compared to long grains. We also note here that neither the random nor {110} texture which is common for BCC materials 9,24) are ideal textures for large recoverable extension. The ideal textures appear to be {100} for Cu-Zn-Al (this texture can be produced by melt-spinning) and {111} for Ti-Ni.…”

Section: Heterogeneous Films 421 Columnar Filmsmentioning

confidence: 99%

Shape-Memory Micropumps

Shu

2002

Mater. Trans.

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Motivated by many experimental efforts to develop suitable shape-memory micropumps, we propose a multiscale framework to study the behavior of pressurized films. We use recoverable deflection as a measure to design large stroke micropumps and develop a model to estimate it. We show that the recoverable deflection of a polycrystalline shape-memory film depends on the transformation strain of the underlying martensitic transformation, the texture and especially on the size effects. We find that flat grains are preferable to long grains in columnar films concerning the purpose of large recoverable strain. We also show that common sputtering texture is not ideal for recoverable deflection in both Ti-Ni and Cu-based shape-memory films. It turns out that {100} Cu-based films may have better behavior than Ti-Ni films. We conclude with comparison with experiment.

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“…According to K. R. C. Gisser [75], the shape memory effect was observed after deposition by magnetron sputtering on substrates heated to -460°C. Conditions such as working pressures used by various authors, are introduced below.…”

Section: Annealing Temperature Of Tini Shape Memory Alloy Deposited Bmentioning

confidence: 99%

Fabrication of TiNi shape memory alloy microactuators by ion beam sputter deposition

Tsuchiya

Davies

1998

Nanotechnology

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We report on the production of thin films of TiNi shape memory alloy, grown by ion beam sputter deposition (IBSD) using a Kaufman-type source, for microactuator applications. IBSD is a vacuum-coating process in which a target is bombarded by accelerated ions from a showered ion beam source and sputtered atoms of the target material are deposited onto a nearby substrate. In this work, argon ions at energies up to 1500 eV and current densities of are used to bombard sectored targets of titanium and nickel in order to deposit TiNi films onto unheated substrates. The films were characterized by electrical resistivity measurements and x-ray reflectometry. R-phase and martensitic transformations are seen without high-temperature annealing and the shape memory properties are compared with those of films prepared by DC and RF magnetron sputtering.

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Oriented nickel-titanium shape memory alloy films prepared by annealing during deposition

Cited by 76 publications

References 3 publications

Heterogeneous Thin Films of Martensitic Materials

Heterogeneous Thin Films of Martensitic Materials

Shape-Memory Micropumps

Fabrication of TiNi shape memory alloy microactuators by ion beam sputter deposition

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