Brittle Torsional Fatigue Crack Initiation in an Otherwise Ductile Environment

Abstract

The results of a torsional fatigue test program on marage 250 steel indicate that the usual fatigue failure mechanism occurs as a flat ductile fracture along the cross section of the test specimens. However, a small number of specimens displayed a small penny-shaped crack on the outer surface at a 45-degree helix, typical of brittle torsional failure, before the final ductile failure. Scanning electron microscope examination showed that the brittle failure was caused by a brittle inclusion on the outside surface of the specimen. Keywords: Titanium.

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Document Details

Document Type
Technical Report
Publication Date
Mar 01, 1990
Accession Number
ADA220858

Entities

People

  • A. A. Kapusta
  • R. R. Fujczak

Organizations

  • United States Army Armament Research, Development and Engineering Center

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies
  • Weapons Technologies

DTIC Thesaurus Topics

  • Air Cooled
  • Chemical Analysis
  • Electron Microscopes
  • Engineering
  • Failure Mode And Effect Analysis
  • Fatigue Tests (Mechanics)
  • Materials
  • Materials Engineering
  • Mechanical Properties
  • Mechanics
  • Microscopes
  • Military Research
  • Scanning Electron Microscopes
  • Shear Stresses
  • Stresses
  • Tensile Strength
  • X Rays

Readers

  • Aerodynamics/Aeronautics.
  • Materials Science (Mechanical Engineering).

Technology Areas

  • Microelectronics