Shape memory characteristics of thermoelastic TiNi system rapid-solidified fibers

Ti₅₀Ni_50-x Cu_x(x = 0, 5, 10, 15 at%) fine fibers (diameter = φ80 μm, length = 20 cm∼1 m) were successfully developed by the arc-melted rapid-solidification method. It has been very difficult to do the conventional melt-work processing from the bulk material of this alloy to very fine fiber because of the brittleness of the especially in the range of Cu ≧ 8 at%. The fibers showed good shape memory effect. As Cu content increased, the temperature hysteresis(=Af-Mf) of recovery strain-temperature curves as well as that in the DSC curves became smaller. The tensile strength showed more than 1000 MPa in Ti₅₀Ni₄₀Cu₁₀ at%. Therefore, the developed rapid-solidified, thermoelastic fine fiber actuator/sensor materials have high potential for applications for micro-machines and the fillers of smart composites.