Shape Memory Characteristics of Thermoelastic TiNi System Rapid-Solidified Fibers

Abstract

Ti50Ni50-xCux (x=0,5,10,15at%) fine fibers (diameter= φ 80 μ m, length=20cm∿1m) 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 from metallic compounds especially in the range of Cu≧8at%. The fibers showed good shape memory effect. As Cu content increased, the temperature hysteresis (=Af-Mf) of recovery strain-temperature curves as well as DSC curves became smaller and the tensile strength showed more than 1000MPa in Ti50Ni40Cu10at%. Therefore, the developed rapid-solidified, thermoelastic fine fiber actuator/sensor materials have high potentiality of applications for micro-machines and the fillers of smart composites.