Accession Number:

ADA089827

Title:

Mechanisms By Which Humidity Alters Ductility.

Descriptive Note:

Technical rept. 15 Apr 79-14 Apr 80,

Corporate Author:

ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER

Report Date:

1980-08-01

Pagination or Media Count:

68.0

Abstract:

The mechanical properties of a thin layer at the surface of aluminum alloys change progressively during fatigue. The alterations are more pronounced and rapid for fatigue in moist than in dry air. The alterations observed as a change in the Ductility of the surface was characterized, and the rates of crack initiation, early growth and the relaxation of residual surface stresses during fatigue are all sensitive to the state of ductility of the surface was found. The depth into the surface affected by environment is too shallow to permit characterization of the surface ductility by conventional techniques. Five parameters, related to different aspects of surface ductility, are defined and methods to measure them are discussed. Results of an initial survey of the relationship of alloy type and heat treatment to the sensitivity of surface ductility to humidity are also described.

Subject Categories:

  • Properties of Metals and Alloys
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE