Non-crystallographic symmetry of liquid metal, flat crystallographic faults and polymorph transformation of the M₇C₃carbide

Abstract

The fine lamellar fault structure of primary MC 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 MC, MC, MC and MC carbides and constructions of the projective 10 Desargues configuration and its subconfigurations is shown. Mutual mapping between 10 Desargues subconfigurations determines transformations of the ten-vertex equal-edged triangulated clusters appearing as building units of these carbides.

Crystal structures of alpha and beta modifications of Mn as packing of tetrahedral helices extracted from a four-dimensional {3, 3, 5} polytope

“…Recently the formation of the phases withand -Mn structure has been observed during devitrification of iron-based metallic glasses (Ljasotsky et al, 2014;Dyakonova et al, 2014). These observations support our spiral polymer model of metallic melts and glasses which has been proposed earlier (Kraposhin & Talis, 2016;Talis et al, 2017). The symmetry constructions which were used here are realized also in the spiral biopolymers with Atomic positions of the -Mn modification in the (001) plane.…”

Formation of the cementite crystal in austenite by transformation of triangulated polyhedra

“…austenite and rhombic Fe 3 C carbide. The rhombus diagonal flipping has been used for the description of transformation in physical objects: a transition between isomers of B 10 C 2 H 12 carboborane molecule (Lipscomb, 1966), polymorphic transformation in metals (Kraposhin et al, 2003;Kondrat'ev et al, 2015), in situ transformation between Fe 3 C cementite and M 7 C 3 or M 23 C 6 carbides (Talis et al, 2017).…”

Improving the Quality of Parts Produced by Bending in a Die with an Elastic Element

“…The new method is suitable for different materials with the same angle [7,17]. Figure 2 shows a diagram of a stamp using an elastic element [8,16].…”