FEATURE Experimental Characterization of Active Materials Series TIPS AND TRICKS FOR CHARACTERIZING SHAPE MEMORY ALLOY WIRE: PART 4 – THERMO-MECHANICAL COUPLING (original) (raw)

T his is the fourth paper in our series, identifyingunusual phenomena and providing recommenda-tions for the thermo-mechanical characterizationof shape memory alloy (SMA) wire. Part 11 pro-vided basic background of the martensitic transformations between austenite (A) and martensite (M) which are respon-sible for the shape memory (SM) effect and superelasticity (SE). Two typical NiTi SMA alloys (SM wire with austenite start temperature As> 20 ◦C and SE wire with austen-ite finish temperature Af < 20 ◦C) were characterized by differential scanning calorimetry (DSC) to measure trans-formation temperatures, specific heats, and latent heats of transformation. SM and SEwere demonstrated for each alloy in their respective temperature regimes. Part 22 reviewed various methods to obtain fundamental sets of isothermal mechanical responses for the two SMA wire alloys. Part 33