1356. HANEMANN, H., HERRMANN, K., HOFMANN, U., AND SCHRADER, A. [Processes in the Formation of the Martensite Structure.] Arch. Eisenhüttenw., vol. 4, 1931, pp. 479-484; Chem. Abs., vol. 25, 1931, p. 4833.

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Literature Abstracts

Martensite system was studied by the most recent röntgenographic methods, and a correlation of the conclusion from recent Röntgen investigations with the facts of micrographs was attempted. The tetragonal, space-centered lattice of hardened steels with 0.91% C as determined by röntgenographs primarily is due to the η-phase. The röntgenographs of steel samples with higher C contents (1.64% C) contain, besides the interferences of the tetragonal lattice, those of cubic face-centered Fe (austenite). A distorted a-Fe lattice with the embedded and adsorbed C atoms exists between the first and second martensite transformations. The röntgenographs show the disappearance of the η-phase on annealing, hardened, high-C steels at 110°, while the photomicrographs show that the needle-formed η-structure is unchanged (a case of pseudomorphism). In photomicrographs the θ-phase is crystalline in form, while in the röntgenographs it shows a primary structure different from that of a-Fe (another case of pseudomorphism). On quenching steels with 0.91”% C from 1,100° and 900° in ice-H₂O and from 900° in oil, the tetragonal structure remains unchanged within wide limits of quenching velocity.

HARA, I. See abs. 1905, 1906b.