Fundamental Structure-Property Relationships for High-Temperature Ceramic Composites

Abstract

Directionally-solidified oxide eutectics such as alumina-YAG and alumina-zirconia show promise as high-temperature structural materials because of their high temperature strength and creep resistance. 1-5 Compatibility constraints at the internal interfaces between the two constituent phases can lead to residual stresses upon thermal cycling and elastic interaction stresses under applied loads. The magnitudes and distributions of these stresses have important ramifications for the mechanical behavior of the composites. Here we investigate thermal stresses in alumina-YAG and alumina-zirconia directionally solidified eutectics (DSEs). First, the microstructure and crystallography are thoroughly characterized. X-ray diffraction is employed to measure the strain tensors in each phase, which are subsequently converted to stress tensors. Since the experimental measurements provide only average stresses in each phase, anisotropic finite element modeling (FEM) is used to investigate stress distributions in the materials. Comparisons between the experimental measurements and FEM results provide insight into possible stress relief.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1999
Accession Number
ADA420672

Entities

People

  • Elizabeth C Dickey

Organizations

  • University of Kentucky

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Ceramic Matrix Composites
  • Composite Materials
  • Crystallography
  • Diffraction
  • Engineered Materials
  • Eutectic Composites
  • Eutectics
  • High Temperature
  • Materials
  • Materials Engineering
  • Materials Science
  • Mechanical Properties
  • Residual Stress
  • Stresses
  • Thermal Stresses
  • X Rays
  • X-Ray Diffraction

Fields of Study

  • Materials science

Readers

  • Mechanical Engineering/Mechanics of Materials.
  • Powder metallurgy of Titanium alloys.