Physical and Mechanical Characterization of Ti50Ni(50−X)FeX Shape Memory Alloy Fabricated by Spark Plasma Sintering Process

Abstract

NiTi smart alloys are known for their characteristic shape memory behavior. The current work focuses on the physical and mechanical characterization of Ni_(50−X)Ti₅₀Fe_X shape memory alloys prepared by the spark plasma sintering (SPS) process and their dependence on the concentration of Fe. The physical characterization of the samples confirmed the presence of the FeNiTi phase along with the Ti- and Ni-rich phases. Enhanced mechanical properties were observed in 8 at. pct Fe samples, which contained secondary intermetallic phases such as Ti₂Ni, Ni₃Ti, Fe₂Ti, and Ni₄Ti₃. Higher fraction of NiTi phase in the 8 at. pct Fe sample resulted in better shape memory properties while showing a higher friction coefficient. Ball on disk wear tests were done to identify the mechanisms contributing to the wear in the sintered sample. It is observed that the abrasive wear as well as the adhesive wear are the most prominent contributors for the surface material removal, and the dependence of characterization is observed with the variation of Fe content in NiTiFe alloy.