Characterization of Fusion Welded Ceramics in the SiC-ZrB₂-ZrC System

Abstract

Various SiC-ZrB2-ZrC ceramics were joined by fusion welding to determine the maximum silicon carbide content that could be joined. Commercial powders were hot pressed, machined, and preheated to 1450 °C before joining with a tungsten inert gas welding torch at 160–200 A. Resulting welds were cross-sectioned and analyzed to determine which compositions were weldable and to characterize microstructural evolution in welded samples. As compositions approached the ternary eutectic, the welds had smaller SiC grains and exhibited better weldability. Penetration depth of welds was controlled by a combination of current input and welding speed. The ternary eutectic in the system was found at 36.9 ± 1.3 vol% SiC, 42.7 ± 1.5 vol% ZrB2, and 20.4 ± 1.9 vol% ZrC and its melting temperature was 2330 ± 23 °C. A ternary phase diagram for the SiC-ZrB2-ZrC was constructed and proposed via microstructural analysis of arc melted pellets on binary joins between each binary eutectic and the ternary eutectic in the system.

Department(s)

Materials Science and Engineering

Keywords and Phrases

Borides; Carbides; Joints/Joining; Phase Equilibria; Ultra-High Temperature Ceramics

International Standard Serial Number (ISSN)

0955-2219

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2021 European Ceramic Society, All rights reserved.

Publication Date

01 Apr 2021

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