Accession Number:

AD0270697

Title:

EFFECT OF SUBSTRUCTURE ON CLEAVAGE IN IRON CRYSTALS

Descriptive Note:

Corporate Author:

SHIP STRUCTURE COMMITTEE WASHINGTON DC

Report Date:

1962-01-29

Pagination or Media Count:

1.0

Abstract:

The influence of substructure on the cleavage transition temperature in iron single crystals was investigated. Substructure was introduced by prestraining up to 10 and annealing, with the dislocation density increasing correspondingly from an initial value of about 10 to the 7th power to about 10 to the 10th power per sq cm. The yield properties of the crystals with substructure were somewhat higher while the brittle transition temperature was raised about 40 C. Twinning preceded cleavage in these tests, and all the cleavage microcracks observed were associated with twins. The microcracks were located either along the twinmatrix interfaces or within the twins, but not in the matrix itself nor at intersecting twins. Cleavage appears to be initiated by the action of twinning, rather than by the role of twins as barriers to slip. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE