Laser annealing of shape memory alloy thin films provides new opportunities in actuator design and fabrication for microelectromechanical systems applications. In this paper, we present a three-dimensional thermal model to simulate the crystallization process when a laser beam is swept across an amorphous NiTi thin film. Experimental crystallite nucleation and growth rates are included in the m...

Shape memory alloys (SMAs) are materials that exhibit a distinct thermomechanical coupling, one that gives rise to a wide variety of applications across a broad range of fields. One of the most successful roles is in the construction of novel medical implants. Unfortunately, concerns have been raised about the biocompatibility of the most popular SMA, nitinol (NiTi), due to the known toxic, all...

Five types of porous Nickel-Titanium (NiTi) alloy samples of different porosities and pore sizes were fabricated. According to compressive and fracture strengths, three groups of porous NiTi alloy samples underwent further cytocompatibility experiments. Porous NiTi alloys exhibited a lower Young's modulus (2.0 GPa ~ 0.8 GPa). Both compressive strength (108.8 MPa ~ 56.2 MPa) and fracture strengt...

In this paper, shape memory alloys (SMAs) (NiTi-based) have been manufactured by casting with a different atomic percentage of silver element (0, 1, 2 and 3 at. % Ag) using Vacuum Arc Remelting (VAR) furnace. The is added to the binary due its excellent properties such as (anti-corrosion, anti-bacterial high electrical conductivity), which make these in wider applications. These percentages (Ni...

A series of experiments is presented examining the thermo-electro-mechanical response of commercially-available, conditioned, shape memory alloy (SMA) wires (Flexinol®, from Dynalloy, Corp.) during cyclic thermomechanical loading. A specialized experimental setup enables temperature control via a thermoelectric/heatsink in thermal contact with the wire specimen during various modes of testing. ...

Shape memory alloys (SMA) show a high ratio of work capacity per material volume. This makes the application of SMA especially useful in micron-sized systems. The development of robotic grippers is one important prerequisite for the successful automation of the assembly of micro systems. Therefore the SMA may also play a role, for example, as actuators in micron-sized grippers. This paper prese...

A novel Shape Memory Alloy (SMA) actuator consisting of a number of thin NiTi bers woven in a counter rotating helical pattern around supporting disks is rst described. This structure can be viewed as a parallel mechanism used to accomplish a highly ee-cient transformation between force and displacement. The actuator overcomes the main mechanical drawback of shape memory alloys, that being limi...

A thermomechanical boundary value problem and constitutive model are presented for a shape memory alloy (SMA) wire under uniaxial loading. The intent is to develop a one-dimensional continuum model of an SMA element that includes all the relevant thermomechanical couplings and is suitable for inclusion in finite element analyses. Thermodynamic relations are derived from phenomenological conside...

Medical staples are one of the nitinol shape memory alloys applications which their pedicles have to be bent for suitable function with an appropriate angle at a specified temperature .It is achievable by shape memory effect. For this purpose, samples of nitinol super elastic alloys were bent in a steel mold with different angles & formed orthopedic staples. Then shape memory effect was induced...

Abstract: In the present study the effect of thermomechanical treatment (cold work and annealing) on the transformation behavior of NiTi shape memory alloys was studied. Differential scanning calorimetry was used to determine transformation temperature and its relation to precipitates and defects. Three alloys including Ti-50.3at.% Ni, Ti-50.5at.% Ni (reclamated orthodontic wires) and 50.6at...