Zirconium Diboride Laminates for Improved Damage Tolerance at Elevated Temperatures

Abstract

The mechanical response was studied for dense laminates containing layers of ZrB2 (~145 µm) and graphite—10 vol% ZrB2 (~20 µm). Individual layers were formulated by mixing starting powders with thermoplastic polymers and pressing into sheets. Laminates were produced by stacking and warm pressing the sheets, debinding, and hot pressing at 2050°C, 32 MPa, in Ar. The laminates were fractured at temperatures up to 2000°C in Ar. Laminates exhibited room temperature flexure strength of 260 MPa, increasing to 300 MPa at 1600°C, and then decreasing to 160 MPa at 2000°C. Inelastic work of fracture was 0.6 kJ/m2 at room temperature, reached a maximum of 1.3 kJ/m2 at 1400°C, and reverted to linear elastic failure at 2000°C. During fracture, cracks were deflected at the interfaces between the strong ZrB2 layers and the relatively weak C-ZrB2 layers, which led to an increased inelastic work of fracture by more than an order of magnitude compared to conventional ZrB2 ceramics. This study demonstrated that laminate architectures are a promising approach for improving the damage tolerance of ZrB2-based ceramics at elevated temperatures.

Department(s)

Materials Science and Engineering

Comments

Air Force Office of Scientific Research, Grant FA9550‐14‐1‐0385

Keywords and Phrases

Damage Tolerance; Laminar Composite; UHTC; Zirconium Diboride

International Standard Serial Number (ISSN)

1546-542X; 1744-7402

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2021 American Ceramic Society, All rights reserved.

Publication Date

01 Jan 2021

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