Tough Ceramics from Fibrous Monoliths.

Abstract

During this 1991-1993 grant, the University of Michigan developed "fibrous monolithic ceramics", a new class of monolithic ceramics with properties comparable to ceramic fiber reinforced ceramic matrix composites CMC's. They consist of a 250-micron "cells" of a strong polycrystalline ceramic, such as silicon carbide or silicon nitride, separated by "cell boundaries" from materials, such as boron nitride, which promote crack deflection and delamination. These materials show graceful failure in flexure, with strengths around 350 MPa and work of fracture around 2000 J/m2. Fibrous monolithic ceramics are made from conventional low-cost ceramic powder, using extrusion methods common in conventional ceramic manufacture. We have demonstrated successful fibrous monoliths with silicon carbide, silicon nitride, and alumina, using weak interfaces of graphite or boron nitride. The boron nitride systems are resistant to oxidation. Their room temperature properties are unaffected by exposure at 1400 deg C.

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Document Details

Document Type
Technical Report
Publication Date
Aug 25, 1997
Accession Number
ADA329890

Entities

People

  • John W. Halloran

Organizations

  • University of Michigan

Tags

Communities of Interest

  • Advanced Electronics

DTIC Thesaurus Topics

  • Ceramic Materials
  • Ceramic Matrix Composites
  • Chemistry
  • Fiber Spinning
  • Material Degradation Processes
  • Materials
  • Materials Engineering
  • Materials Laboratories
  • Materials Processing
  • Materials Science
  • Mechanical Working
  • Modulus Of Elasticity
  • Oxidation
  • Silicon Carbide
  • Structural Ceramics
  • Technical Ceramics

Fields of Study

  • Materials science

Readers

  • Reinforced Composite Materials