Accession Number : AD0281895

Title :   THE 1962 HOWE MEMORIAL LECTURE ON THE STRENGTHENING OF STEEL,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE

Personal Author(s) : Cohen,Morris

Report Date : 01 APR 1962

Pagination or Media Count : 48

Abstract : The strength of martensite in hardened steels seems to be due basically to solid-solution hardening contributed by the carbon atoms occupying interstitial sites in the body-centered lattice of iron. The severe local and nonsymmetrical displacements of the neighboring iron atoms produce dipole distortions that interact strongly with dislocations. The observed magnitude of such solid-solution hardening requires that the effective dislocation length be of the order of 100 angstroms. This distance is identified with the fine-scale twin spacing which is actually found in the Fe-Ni-C martensites studies. These hardening features are especially clear in Fe-Ni-C martensites because the latter can be formed and tested at subzero temperatures where C-diffusion processes are not operative. In the conventional hardening of steel by quenching to room temperature, or in the room-temperature aging of refrigerated martensite, C-precipitation hardening sets in and furnishes a further increment of strength which is subject to considerable manipulation by thermal and mechanical treatments. (Author)

Descriptors :   *HARDENING, *MARTENSITE, *STEEL, ATOMS, CARBON, CARBON ALLOYS, CRYSTAL DEFECTS, CRYSTAL LATTICES, CRYSTAL STRUCTURE, IRON ALLOYS, MECHANICAL PROPERTIES, NICKEL ALLOYS, PHASE STUDIES, THEORY

Distribution Statement : APPROVED FOR PUBLIC RELEASE