SHAPE MEMORY BEHAVIOR AND ONE-WAY SHAPE MEMORY EFFECT OF A NiTi SHAPE MEMORY BANDS

Alina Niculescu^*, Ioan Ştefănescu, Amalia Soare, Mihai Vijulie, Sebastian Brad

National Research and Development Institute for Cryogenics and Isotopic Technologies - ICIT Rm. Valcea, code 240050 - Rm. Valcea, 4 Uzinei Street, PO Box 7 Raureni, Valcea, Romania

ABSTRACT

To define the alloy’s shape, this is constrained under deformation and then heat treated. The one-way shape memory effect in a NiTi high temperature shape memory alloy  has been systematically studied by bending tests. In the NiTi alloy, the martensite deformation is an effective method to get two-way shape memory effect even with a small deformation strain. Internal structure and shape memory behavior of NiTi bands heat-treated at 100 K, 200 K, and 300 K were investigated by Scanning Electron Microscopy (SEM) and X-ray fluorescence at room temperature. The NiTi shape memory bands were supplied by Memry Company, with following thickness: 0.05mm, 0.5mm, 1.25mm, 0.203mm.  The results showed that the NiTi bands possess super-elastic properties, and the transformation temperature is 113°C; also, it has been noticed that the alloy has a higher content of titanium and exhibit shape memory effect.

KEYWORDS: Ni-Ti shape memory alloys, one-way shape memory effect, shape memory effect, martensite