The Influence of Absorbed Moisture on Fatigue Crack Propagation Behavior in Polyamides. Part B. Fractography.

Abstract

The fatigue fracture surface morphology of nylon 66, nylon 6 and nylon 612 was examined to ascertain mechanisms of fatigue crack propagation (FCP) in these polymers. Attention was also given to noting any correlation between fracture surface markings and macroscopic fatigue crack growth rate data. In general, observed changes in fracture surface appearance reflected an increasing level of plastic deformation with increasing water content, particularly in N66 and N6. Classical fatigue striations were identified in specimens of N66 and N6 containing 1.7-5.7 wt% water. Other types of fracture lineage of unknown origin were also seen which can confound the interpretation of fatigue fracture topography. Unlike the cases of N6 and N66, the fracture of N612 was dominated by a microvoid coalescence mechanism at all moisture levels and at all Delta K levels examined. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Jan 30, 1981
Accession Number
ADA096070

Entities

People

  • John A. Manson
  • Philip E. Bretz
  • Richard W. Hertzberg

Organizations

  • Lehigh University

Tags

Communities of Interest

  • Air Platforms
  • Weapons Technologies

DTIC Thesaurus Topics

  • Chemical Engineering
  • Chemistry
  • Coalescence
  • Cracks
  • Engineering
  • Engineers
  • Fractography
  • Geography
  • Materials
  • Materials Engineering
  • Materials Laboratories
  • Materials Science
  • Military Research
  • Moisture
  • Moisture Content
  • Plastic Deformation
  • United States

Readers

  • Materials Science (Mechanical Engineering).
  • Polymer Science and Engineering.
  • Systems Analysis and Design