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 ½001
ferrite pole from ½110ðFe;MnÞ3AlC pole in Nishiyama-Wasserman orientation relationship
and the coincidence of ½111
ferrite and ½110ðFe;MnÞ3AlC 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.