Structural evolution and thermal stability of functionally graded NiTi nano-glass thin films alloys during crystallization

Functionally graded NiTi shape memory alloys

In this study, in order to obtain a functionally graded material, NiTi strips were annealed at 350°C, 450°C and 550°C in a furnace using an assembly that allowed a temperature gradient along them, and their transformation temperatures were studied by Differential Scanning Calorimetry (DSC). Furthermore, the strips were bent at both ends and dipped into a water bath at room temperature which was...

Thermal Stability of Thin Rectangular Plates with Variable Thickness Made of Functionally Graded Materials

In this research, thermal buckling of thin rectangular plate made of Functionally Graded Materials (FGMs) with linear varying thickness is considered. Material properties are assumed to be graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. The supporting condition of all edges of such a plate is simply supported. ...

Crystallization kinetics of amorphous NiTi shape memory alloy thin films

The temperature dependence of the crystallite nucleation and growth rates is measured for amorphous NiTi thin films. Using transmission electron microscopy, crystallites are shown to nucleate homogeneously in the film and to grow in a channeling mode. A mechanism that suppresses heterogeneous nucleation is proposed. By manipulating nucleation and growth rates, grains as large as 60 lm can be ob...

Thermal modeling of laser-annealing-induced crystallization of amorphous NiTi thin films

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...

Glass transition and crystallization of amorphous Ni–Ti–Zr thin films by combinatorial nano-calorimetry