A well-known eutectoid reaction takes place in steels. When
binary Fe–C alloys containing about 0.77 wt.% C are cooled
below the eutectoid temperature, the eutectoid reaction takes
place involving the decomposition of austenite into ferrite and
cementite. The product phases of the eutectoid reaction feature
pearlite, comprising lamellar ferrite and cementite [1]. The
pearlite colonies nucleate most easily at the original austenite
grain boundaries. The lattice parameters of M3C carbide are
adopted as a=0.4524 nm, b=0.5089 nm, and c=0.6743 nm.
Orientation relationships (ORs) between the ferrite and cementite
have been well documented in the literature. For example,
Bagaryatsky's OR between the ferrite (α) andM3C (C) is [110]α//
[100]C, [111]α//[010]C and (112)α//(001)C. Isaichev's OR is [111]α//
[010]C and (011)α//(103)C [2–4].