Elastic Properties of NiTi as a Function of Temperature

Abstract

Young's modulus, shear modulus, and internal friction of the intermetallic compound NiTi have been measured as a function of temperature from about −180° to 600°C, in the kilocycle-per-second range. Annealed and cold-worked specimens were used. All the specimens showed the same general pattern, with a minimum in elastic moduli occurring about 70°–140°C, depending upon the particular specimen, and a maximum in internal friction occurring some 50°C below the minimum in elastic modulus. Young's modulus was the same for all the specimens (694 kbar) within experimental error, but the shear modulus of the cold-worked specimens was more than 10% higher than that for the annealed specimens.

Ultrasonic measurement of anisotropy and temperature dependence of elastic parameters by a dry coupling method applied to a 6061-T6 alloy

“…Equivalent measurement campaigns performed on AG3 or 5754 aluminium alloy have also given us a Young's modulus estimation by ultrasonic means higher than the value given by the fatigue tests with almost the same discrepancy as for the 6061-T6 sample. Similarly, Young's modulus measured by a resonance technique in the kilocycle range for NiTi material has been found lower than estimation obtained from ultrasonic measurement at 5 MHz [12]. For ceramics, a 10% deviation for the elastic constants has been found between ultrasonic investigation and mechanical tensile testing [13].…”

Influence of cold work and texture on the high-strain-rate response of Nitinol

“…Contrary to the trend observed in typical bcc metals and alloys, the critical stress did not decrease with increase in temperature for both the cold-worked and annealed sheet at 1200/s. Although the reason for this trend is not currently known, an increase in the yield stress and the elastic modulus of Ni-Ti alloy with increasing temperature has been noted elsewhere [65,68,69]. Therefore, cold working not only endows the Ni-Ti alloy with higher plateau stress (due to increase in the resistance to slip), but also increased the austenite strength at higher temperatures.…”

Technique development for modulus, microcracking, hermeticity, and coating evaluation capability characterization of SiC/SiC tubes

“…The origin of using resonance frequencies to determine mechanical properties can be traced to 1945 when Spinner and Tefft presented a method for determining the resonance frequencies and extracting the elastic modulus from these frequencies [26]. Spinner and Tefft led the research work: determining the elastic properties from the longitudinal, flexural, and torsional vibrations at room or elevated temperatures [27][28][29][30]. Better equipment and advancements in computing technology have led to widespread use of this technique in various fields [31][32][33][34][35].…”