Densification, Microstructure, and Mechanical Properties of ZrC-SiC Ceramics

Abstract

ZrC-SiC ceramics were fabricated by high-energy ball milling and reactive hot pressing of ZrH2, carbon black, and varying amounts of SiC. The ceramics were composed of nominally pure ZrC containing 0 to 30 vol% SiC particles. The relative density increased as SiC content increased, from 96.8% for nominally pure ZrC to 99.3% for ZrC-30 vol% SiC. As SiC content increased from 0 to 30 vol%, Young's modulus increased from 404 ± 11 to 420 ± 9 GPa and Vickers hardness increased from 18.5 ± 0.7 to 23.0 ± 0.5 GPa due to a combination of the higher relative density of ceramics with higher SiC content and the higher Young's modulus and hardness of SiC compared to ZrC. Flexure strength was 308 ± 11 MPa for pure ZrC, but increased to 576 ± 49 MPa for a SiC content of 30 vol%. Fracture toughness was 2.3 ± 0.2 MPa·m1/2 for pure ZrC and increased to about 3.0 ± 0.1 MPa·m1/2 for compositions containing SiC additions. The combination of high-energy ball milling and reactive hot pressing was able to produce ZrC-SiC ceramics with sub-micron grain sizes and high relative densities with higher strengths than previously reported for similar materials.

Department(s)

Materials Science and Engineering

Keywords and Phrases

Densification; Mechanical properties; Microstructure; Reactive hot pressing; Zirconium carbide-silicon carbide ceramics

International Standard Serial Number (ISSN)

0002-7820; 1551-2916

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2019 The American Ceramic Society, All rights reserved.

Publication Date

01 Oct 2019

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