Accurate determination of orientation relationship between ferrite and (Fe, Mn)3AlC in an Fe-Mn-Al-C eutectoid alloy

[Display omitted] •Full eutectoid structure of α-ferrite + κ-carbide is developed in an Fe-Mn-Al-C alloy.•The exact orientation relationship between α and κ is determined.•Multi-scale analyses are performed to clarify the orientation relationship α and κ.•Coherencies at K-S and N-W orientation relationships of α and κ are calculated and compared. The orientation relationship between ferrite and (Fe,Mn)3AlC has been investigated in an Fe-3.5Mn-5.8Al-1.05C based eutectoid alloy. Electron diffraction pattern analysis shows two possible orientation relationships between both phases. Accurate analysis using convergent beam electron diffraction reveals the deviation of [001]ferrite pole from [110](Fe,Mn)3AlC pole in Nishiyama-Wasserman orientation relationship and the coincidence of [111]ferrite and [110](Fe,Mn)3AlC poles in Kurdjumov-Sachs orientation relationship. Transmission Kikuchi diffraction resolves the orientation of several tens nanometer scales of ferrite+(Fe,Mn)3AlC lamellar. Kurdjumov-Sachs orientation relationship between ferrite and (Fe,Mn)3AlC is clarified by the comparison of deviation angle from both orientation relationships. Coherency at the interphase boundaries is further discussed.