Thermomechanical characterization of high temperature SMA actuators

Abstract

The focus of this paper is the study and thermomechanical characterization of High Temperature Shape Memory Alloys (HTSMAs) at different stress levels and temperatures ranging from 300 to 500°C. The stability of the material response under cyclic actuation is also investigated. The observations deduced from the tests are presented in detail. In order to investigate the above issues a Ti₅₀Pd₄₀Ni₁₀ HTSMA was used. The alloy was fabricated by a vacuum arc melting technique, followed by casting and hot rolling. A high temperature experimental setup was developed on a load frame to test the material at high temperatures under constrained actuation conditions. Certain key observations on the material response, in terms of recoverable strains under various applied total strains and actuation stress levels, and cyclic thermomechanical behavior are presented.