Influence of the precipitates on the shape memory effect and superelasticity of the near–eutectoid Ti–Au–Fe alloy towards biomaterial applications

Investigations of Effects of Intermetallic Compound on the Mechanical Properties and Shape Memory Effect of Ti–Au–Ta Biomaterials

“…Therefore, in Section 3.1 , the specimen of the Ti–4Au–30Ta alloy, which could not be cold–rolled at RT, could be attributed to the embrittlement brought from the Ti 3 Au precipitates. Hence, the cold workability agreed well with the phase constituents observed by the X–ray diffraction patterns ( Figure 1 ) and the literatures [ 35 , 38 , 41 , 42 ]. More details of the Ti 3 Au precipitates concerning its microstructure are shown in Section 3.3 .…”

“…The size of the oval–shaped precipitates was approximately 1–3 μm and the volume fraction of the precipitates was about 5%. It is also worth mentioning that the microstructure of the precipitates was found very similar with those in the literature [ 38 ]. More details concerning the precipitates in the Ti–4Au–30Ta alloy are explained by the elemental mapping results in the following.…”

“…On the other hand, the precipitates were high in Au ( Figure 2 d) and low in Ta ( Figure 2 e). Given that the Ti 3 Au phase was determined by the X–ray diffraction pattern of the Ti–4Au–30Ta alloy ( Figure 1 b) and the literature [ 35 , 38 , 41 , 42 ], it thus could be concluded that the precipitates in bright contrast could be corresponded to the Ti 3 Au phase. In addition, it was reported that the Ti 3 Au phase is a line compound [ 37 ]; therefore, the solubility of Ta was extremely low (i.e., dark contrast) to the Ti 3 Au intermetallic compound.…”

“…On the other hand, in addition to the parent β–phase, a compound with a crystal structure of A15 was also found in the (b) Ti–4Au–30Ta alloy. According to the literature [ 37 , 38 ], the compound possessing A15 crystal structure corresponds to the intermetallic compound of Ti 3 Au. More analysis concerning the Ti 3 Au with an A15 crystal structure are shown in Section 3.3 via microstructure observations and chemical composition analysis.…”

“…On the other hand, according to the literature, the intermetallic compound of Ti 3 Au, which is a brittle phase and is often found in the Ti–Au–based alloys [ 35 , 38 , 41 , 42 ], could deteriorate the cold workability of the specimens. Therefore, in Section 3.1 , the specimen of the Ti–4Au–30Ta alloy, which could not be cold–rolled at RT, could be attributed to the embrittlement brought from the Ti 3 Au precipitates.…”