Effect of Preannealings on the Temperature Spectra of Internal Friction and Shear Modulus of Ti–51Ni

Abstract

Internal friction, shear modulus and released shear strain of Ti–51Ni are measured with an inverted torsion pendulum in the temperature range between 90 and 350 K both in heating and in cooling runs. The effects of preannealing temperature Ta on their temperature spectra are systematically investigated. Only premartensitic transformation is observed for 573 K≤Ta≤773 K, both premartensitic and martensitic ones for 873 K≤Ta≤1073 K, and only martensitic one for Ta≥1173 K. Precipitation and retained high temperature phase are supposed to play an important role in these transformation variations. A peak observed at 200 K for Ta≤773 K is shown to be of a relaxation-type and to have nothing to do with the transformations.