Accession Number:

AD0281895

Title:

THE 1962 HOWE MEMORIAL LECTURE ON THE STRENGTHENING OF STEEL,

Descriptive Note:

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE

Personal Author(s):

Report Date:

1962-04-01

Pagination or Media Count:

48.0

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

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE