Fibrous Monoliths: Non-Brittle Fracture from Powder-Processed Ceramics

Abstract

Fibrous monoliths are non-brittle ceramics, fabricated from conventional powders using new methods that create a fibrous mesostructure to obtain an in situ composite. Ceramic-BN fibrous monoliths fracture like wood, with graceful failure occurring by shear delamination. Examples are Si3N4-BN fibrous monoliths, which have flexural strengths around 460 MPa between room temperature and 1000 ⁰C and retain about half of their load-bearing ability after failure initiates, which apparent fracture energies up to 4800 J m-2 (SiC-alloy)-BN fibrous monoliths have flexural strengths around 400 MPa and exhibit graceful failure between room temperature and 1200 ⁰C. Ceramic-metal fibrous monoliths also have graceful failure. Results are presented for (yttria-zirconia)-Ni fibrous monoliths, which fail by tensile cracking, with crack bridging by ductile metal ligaments. About 25 vol.% Ni imparts a fracture energy of 2200 J m-2, with a strength of 574 MPa.

Department(s)

Materials Science and Engineering

Keywords and Phrases

Ceramics; Fibres; Fracture; Monoliths; Powders; Bearing capacity; Ceramic matrix composites; Crack initiation; Delamination; Fabrication; Failure (mechanical); Strength of materials; Structure (composition); Temperature; Crack bridging; Ductile metal ligaments; Fibrous mesostructure

International Standard Serial Number (ISSN)

0921-5093

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1995 Elsevier BV, All rights reserved.

Publication Date

01 Jun 1995

Link to Full Text

Share

 
COinS