Effect of the strain rate and test temperature on the mechanical properties of a Ti-Ni-Fe shape memory alloy

Abstract

The test temperature (from −196 to +50°C) and the strain rate (from 10−4 to 103 s−1) are found to affect the character of deformation of a shape memory alloy TN1K based on titanium nickelide and alloyed with iron. The shapes of the tensile and compressive curves are shown to depend on the position of the test temperature with respect to the characteristic phase-transition temperatures. The mechanical properties are extremal in the temperature ranges corresponding to the R phase region. As the strain rate increases in the quasi-static range, the strength characteristics of the material increase and the plastic characteristics decrease. As the strain rate increases in the quasi-static range, the yield strength changes analogously; in this case, a yield drop appears in the compressive and tensile stress-strain diagrams. The data obtained are used to optimize the technology of the thermomechanical joints of pipelines and construction elements.