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

Omega(ω)phase has a trigonal or hexagonal crystal structure and was first discovered in β-type Ti-Cr alloys[1].Since then,theω-phase has been widely reported in numerous group Ⅳ transition metal(Ti,Ta,Hf,and Zr)based alloys[2-9].The morphologies ofω-phase could be particle-like(athermal ω-phase)[10],ellipsoidal or cuboidal after aging(isothermal ω-phase)[11],and plate-like af-ter deformation(stress-related ω-phase)[12].Amongst,the stress-related ω-phase is usually located at the twinning boundary,thus also called interfacial-twin-boundary-ω(ITB-ω)phase.The forma-tion of the ITB-ω phase is considered to be related to the forma-tion of{112}bcc<111>mechanical twin(i.e.,{112}bcc twin)in body-centered cubic(BCC)metals and alloys[13].