Thermal Analysis of Ni-Ti-X Alloys Prepared by Self-propagating High-temperature Synthesis

In this work, the influence of alloying elements on the transformation temperatures and temperatures of formation of NiTi intermetallic phases were investigated. NiTi alloys are characterized by shape memory effect, pseudoplasticity and superelasticity. These properties strongly depend on the alloy composition in binary Ni-Ti and ternary Ni-Ti-X. Because these alloys are used in various branches of industry, such as aerospace, engineering or medicine, the addition of ternary element can influence their application significantly. Especially, the presence of Ti2Ni and Ni3Ti in the NiTi matrix may cause a degradation of the shape memory behaviour and mechanical properties. For this reason, we observed the formation of intermetallics by differential thermal analysis (DTA). Differential scanning calorimetry (DSC) experiments were performed to monitor the evolution of the transformation characteristics. We report new results, which show the strong dependence of the transformation temperatures between austenite and martensite on the alloy composition, and how the alloying elements (Mg, C, Zr) influence the formation of Ni-Ti phases. © 2016 Published by Manufacturing Technology. All Rights Reserved.