Non-crystallographic symmetry of liquid metal, flat crystallographic faults and polymorph transformation of the M₇C₃ carbide

The fine lamellar fault structure of primary M₇C₃ carbide particles in the heat-resistant Fe–Cr–Ni–C alloy of the HP series (0.45C–25Cr–35Ni) in the cast condition has been revealed using transmission electron microscopy. The lamellar fault structure is regarded as an inheritance of the initial melt structure. A one-to-one correspondence between the crystal structures of M₇C₃, M₅C₂, M₃C and M₂₃C₆ carbides and constructions of the projective 10₃ Desargues configuration and its subconfigurations is shown. Mutual mapping between 10₃ Desargues subconfigurations determines transformations of the ten-vertex equal-edged triangulated clusters appearing as building units of these carbides.