Mechanisms By Which Humidity Alters Ductility.

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.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Aug 01, 1980
Accession Number
ADA089827

Entities

People

  • J. W. Wert
  • Michael R. James
  • O. Buck
  • Robert C. Chang
  • W. L. Morris

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Alloys
  • Crystal Structure
  • Environment
  • Experimental Data
  • Finite Element Analysis
  • Hardening
  • Materials
  • Measurement
  • Mechanical Properties
  • Numerical Analysis
  • Plastic Deformation
  • Residual Stress
  • Shear Stresses
  • Stress Strain Relations
  • Stresses
  • Tensile Stress
  • Yield Strength

Fields of Study

  • Materials science

Readers

  • Mathematics or Statistics
  • Powder metallurgy of Titanium alloys.
  • Structural Health Monitoring of Composite Structures.