Ti-50.2Ni-5Zr Shape Memory Alloy Square Rots Production by the Casting Technique

Abstract

The purpose of this study is to make the Ti-Ni-Zr specimen using casting method from P/M ingot and evaluates the shape memory behavior. All samples were square rod shape made by centrifugal casting. The size of all samples was 1 mm wide, 1.3 mm height and 37.5 mm length. The transformation behavior during cooling and heating was investigated using a differential scanning calorimeter (DSC). The phase constituent was determined by XRD analysis from 20 °C to 150 °C. Mechanical properties of the shape memory effects were measured using a tensile machine at 25 °C. The samples were annealed at 400 °C, 500 °C and 600 °C for 3.6 ks followed by water quenching. After annealing, specimens were cold rolled at 0 % (no rolling) and 10 %. The Ti-Ni-Zr square rod specimens are fabricated by centrifugal casting using P/M ingot. All samples had shape memory behavior. From DSC measurement, the highest reverse martensitic transformation temperature is 120 °C. From tensile test, the Luders like deformation stress were not constant and dependence of heat treatment conditions was not clarified. However, 10% cold rolling specimen, shape memory characteristics were stabilized.