Deformation-induced interfacial-twin-boundary ω-phase in an Fe48Mn37Al15 body-centered cubic metastable alloy

ω-phase transformation, which plays a key role in modifying mechanical properties, is widely observed in group IV transition alloys. However, the widely accepted ω-phase has not been found in body-centered cubic (BCC) Fe-based alloys yet. In this study, an Fe48Mn37Al15 alloy displayed α → γ` martensitic transformation during a 6%–21% compressive process, and {112}bcc<111> mechanical twinning occurred at 21% compressive strain. Furthermore, a thin layer of interfacial-twin-boundary ω-phase was confirmed located at the boundaries of twinning in this alloy. The possibility of artifacts ω-phase in Fe48Mn37Al15 alloy was carefully ruled out via transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) observation. Therefore, a deformation-induced interfacial-twin-boundary ω-phase has been proven to be formed in an Fe48Mn37Al15 alloy during the compression process. In addition, this ω-phase was analyzed and found to agree with the classic crystallographic orientation relationship with both α matrix and {112}bcc twin. Hence, a geometrical model was schematically used to analyze the formation process of the interfacial-twin-boundary ω-phase.