Abstract
In the case of Precipitation of cementite from austenite, at first, carbon atoms enter regularly into widest spaces of the face centred cubic lattice of iron atoms, and then this lattice causes, at the same time, a sort of simple shear to the directions [001] and [110] in the planes (120) and (113), respectively. By these shears, the carbon atom is surrounded by six iron atoms which form a regular prism of a triangular isoscelses basis and the formation of cementite is completed, if the whole contraction or expansion is neglected. By the similar mechanism, the formation of cementite from martensite is explained.
