Morphology of some eutectics in steels

Autor: L. N. Bagnyuk, Ya. N. Malinochka, Yu. S. Shmelev, M. A. Olikhova
Rok vydání: 1982
Předmět:
Zdroj: Metal Science and Heat Treatment. 24:3-8
ISSN: 1573-8973
0026-0673
DOI: 10.1007/bf00699306
Popis: 1. In manganese and vanadium eutectics, the sulfide phase in a eutectic grain (colony) grows from a single center and is a single-branched formation whose branches are in the form of oval section rods curved to different degrees. Simultaneously and together with the sulfide skeleton eutectic, austenite crystallizes forming a continuous matrix for the eutectic colony. With free growth, eutectic grains take on a globular form, and after inter-growth they form equiaxed grains. 2. In colonies of sulfide eutectic the sulfide phase TiS also has the form of a continuous skeleton with lamellar and rod-shaped branches. In contrast to manganese and vanadium sulfides, during hot rolling titanium sulfides do not deform and they fail in a brittle manner. 3. In grains of vanadium carbide eutectic, the carbide is a continuous-branched formation with branches in lamellar and rod-shaped form. Lamellae in slowly cooled steel start to grow from a framework of cubic crystals of pseudoprimary carbide arising in the eutectic liquid. Rod-shaped branches may have both a regular growth direction and a randomly varying direction under the influence of the jointly growing austenite matrix. 4. The structure of titanium and niobium carbide colonies is similar to the structure of vanadium carbide eutectic colonies. 5. In steels with pellicular eutectic sulfides (carbides) these sulfides (and apparently carbides) are in the form of continuously branched formations, but they branch into a continuous film of crystallizing eutectic liquid between neighboring austenite dendrite branches. 6. The continuity of a sulfide (carbide) phase in eutectic colonies significantly worsens the negative effect of eutectic sulfides (carbides) on ductility and impact strength of cast and also rolled steel perpendicular to the rolling direction.
Databáze: OpenAIRE
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