Iron-based shape memory alloys are promising candidates for large-scale structural applications due to their cost efficiency and the possibility of using conventional processing routes from the steel industry. However, recently developed alloy systems like Fe–Mn–Al–Ni suffer from low recoverability if the grains do not completely cover the sample cross-section. To overcome this issue, here we show that small amounts of titanium added to Fe–Mn–Al–Ni significantly enhance abnormal grain growth due to a considerable refinement of the subgrain sizes, whereas small amounts of chromium lead to a strong inhibition of abnormal grain growth. By tailoring and promoting abnormal grain growth it is possible to obtain very large single crystalline bars. We expect that the findings of the present study regarding the elementary mechanisms of abnormal grain growth and the role of chemical composition can be applied to tailor other alloy systems with similar microstructural features.

The current work presents the results of a study of the thermal stability of metastable ω‐Ti(Fe) produced by a high‐pressure torsion process and describes the phase transformations of ω‐Ti(Fe) upon heating. The titanium alloys under study contain between 1 and 7 wt% of iron, the phase transitions are investigated using a combination of in situ high‐temperature X‐ray diffraction and differential scanning calorimetry. The high‐temperature X‐ray diffraction reveals the phase sequence ω → α' → α + β → β upon heating. The differential scanning calorimetry shows that the first phase transformation is exothermal and that the temperature of this phase transition is independent of the iron concentration within the composition range under study. Subsequent phase transitions are endothermal and the respective transition temperatures depend on the iron concentration. The differences between the phase stabilities conclude from the phase diagram and the phase stabilities observe experimentally are explained by the partial coherence of the α/α′‐Ti and β‐Ti grains.