Effect Of Rolling On Ni-Ti-Fe Shape Memory Alloys Prepared Through Novel Powder Metallurgy Route

Effect of Fe Addition on Microstructure and Mechanical Properties of As-cast Ti49Ni51 Alloy

“…In early studies, the cold-rolled Ti 50 Ni 47.5 Fe 2.5 (at.%) alloy has two-way shape memory effect and low martensite transformation temperature [19]. Due to the excellent shape memory effect of Ti-rich Ti–Ni–Fe alloys, some researchers have developed the different Ti-rich Ti–Ni–Fe alloys [18,19,20,21,22,23,24,25,26,27,28]. The shape memory effect of Ti 50 Ni 47 Fe 2.5 Nd 0.5 alloy is improved when the trace amount of Nd is substituted for Ni [20], comparing with the Ti 50 Ni 47 Fe 2 Mo 1 and Ti 50 Ni 48 Fe 2 alloys [21,22].…”

“…In fact, the Ti 50 Ni 48 Fe 2 alloy can maintain stable phase transition temperature after 50 thermal cycles [25]. In recent years, the microstructures of hot deformed Ti 50 Ni 47 Fe 3 alloy reported are strain localization, grain boundary serrations, and relatively fine near-equiaxed grains; at higher working temperature and higher strain rate, the content of dynamic recrystallization is higher; the increase of dynamically recrystallized grains results in the restraint of austenitic ↔ martensitic transformation [26,27]. Liang et al [28] reported that the Ti 51.8 Ni 45 Fe 3.2 alloy comprises a B2 austenite matrix and a Ti 2 Ni precipitate, and in the Ti 51.8 Ni 44 Fe 3.2 Nb 1 alloy with high yield strength, the Ti 2 Ni and β-Nb precipitates occur in the matrix of B2 austenite.…”

“…Liang et al [28] reported that the Ti 51.8 Ni 45 Fe 3.2 alloy comprises a B2 austenite matrix and a Ti 2 Ni precipitate, and in the Ti 51.8 Ni 44 Fe 3.2 Nb 1 alloy with high yield strength, the Ti 2 Ni and β-Nb precipitates occur in the matrix of B2 austenite. In the Ti-rich Ti–Ni–Fe alloys, to obtain a large number of B2 TiNi phases, the heat-treated ingots were at high temperature for a long time, and the samples were cooled rapidly in ice water after heat treatment [18,19,20,21,22,23,24,25,26,27,28]. After heat treatment, some researchers have carried out subsequent high temperature forging, or low-temperature aging treatment, or thermal cycle to further study the relationship between microstructure, phase transformation and mechanical properties [18,19,20,21,22,23,24,25,26,27,28,29].…”