Available online at www.sciencedirect.com ScienceDirect Materials Today: Proceedings 4 (2017) 11251–11259 www.materialstoday.com/proceedings 2214-7853 © 2017 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of Advanced Materials, Manufacturing, Management and Thermal Science (AMMMT 2016). AMMMT 2016 The Influence of Alloying Constituent Fe on Mechanical Properties Of NiTi Based Shape Memory Alloys Naresh H a , Bharath H S b , Prashantha S c a Christ University, Bengaluru-560074, India b Siddaganga institute of technology, BH, Road Tumkur- 572106, India c Siddaganga institute of technology, BH, Road Tumkur- 572106, India Abstract The influences of Fe-addition on phase transformation behavior, mechanical properties and microstructure of Ti50Ni50-xFex alloys were investigated by means of optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Results indicate that, as a substitute for Ni, Fe added to TiNi alloys can dramatically decrease the martensite transformation temperature and R phase transformation and martensite transformation are accordingly separated. The results show that TiNiFe alloys exhibit two-step martensitic transformation. The start temperature of martensitic transformation increases sharply from 212 K to 267 K when 2 % Fe is added in, and then decreases gradually if Fe content further increases. The hardness of TiNiFe ternary alloys before heat treatment is constant for up to 6% of the composition and suddenly increases for 9% composition and also it behaves same for heat treated specimens because of formation of equilibrium precipitates Ni3Ti formation. © 2017 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of Advanced Materials, Manufacturing, Management and Thermal Science (AMMMT 2016). Keywords: TiNiFe; Shape Memory Alloy; Martensite Transformation; Mechanical Properties; Microstructure. 1 Introduction Near-equiatomic NiTi shape memory alloys (SMAs) have found wide application in aerospace, aviation, and medical industries owing to their superior functional properties of shape memory effect (super elasticity), biocompatibility as well as excellent mechanical properties [1-16]. In order to modify and ameliorate the properties of the NiTi alloys to meet specific requirements by unique users, addition of tiny amounts of some alloying elements into the binary and ternary SMAs has become a well-known adopted means and way. However, different alloying elements will exert different influences upon the alloys having the identical basic composition. For example, in the ternary alloys Ni-Ti-X, if X is referred to Pd, Hf, Pt, or Zr, they exhibit relatively