Fracture Analysis of Reaction-Bonded Silicon Nitride Turbine Shrouds.

Abstract

Reaction-bonded silicon nitride turbine shrouds were examined after engine rig testing to determine failure mechanisms and evaluate material quality. Bend test specimens machined from the shrouds were approximately equal in strength to specimens cut from flat billets of virgin material. While most component and bend specimen fractures initiated at surfaces, internal origins were observed in some cases. Fracture mechanics analysis of as the bend test data yielded a value of KIc = 1.79 MN/m cubed/2 in agreement with literature data. Fracture mirror measurements indicated that shrouds failed at stresses approximately three times less than bend specimen. Probable causes for this were gross machining defects, size effects, and possible residual stresses.

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Document Details

Document Type
Technical Report
Publication Date
Jun 01, 1982
Accession Number
ADA120769

Entities

People

  • Donald R. Messier
  • George D. Quinn
  • James C. Napier
  • Liselotte J. Schioler

Organizations

  • United States Army Research Laboratory

Tags

Communities of Interest

  • Advanced Electronics
  • Biomedical
  • Space
  • Weapons Technologies

DTIC Thesaurus Topics

  • Air Force
  • Ceramic Materials
  • Databases
  • Engineering
  • Fracture (Mechanics)
  • Information Processing
  • Manufacturing
  • Materials
  • Materials Engineering
  • Materials Science
  • Measurement
  • Mechanical Properties
  • Mechanics
  • Military Research
  • Residual Stress
  • Standards
  • Turbines

Readers

  • Combustion and Flow Dynamics.
  • Reinforced Composite Materials
  • Structural Health Monitoring of Composite Structures.