Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, cilt.44, sa.10, ss.4429-4433, 2013 (SCI-Expanded)
Electrical resistance variations of Ni50.9Ti49.1 shape memory wires were studied during aging treatment at different temperatures via in-situ electrical resistance measurement. The results showed that during aging treatment, a cyclic behavior was observed in the electrical resistance variations, which could be related to the precipitation process. The evaluation of transition temperatures was conducted, after aging, using differential scanning calorimetry (DSC) analysis. The precipitation process is found to occur in four different stages. The results show that depending on the stress level around precipitates, two-, three-, or four-step martensitic transformation could be observed in DSC curves. In the points with maximum stress level (during precipitation process), four-step martensitic transformation is observed. © 2013 The Minerals, Metals & Materials Society and ASM International.