Mechanical Behavior and Applications of Plasma Arc Welded Ceramics

Abstract

Zirconium diboride and zirconium carbide-based ceramics were joined by plasma arc welding to demonstrate the versatility of this technique. A parent material composition consisting of ZrB2 with 20 vol% ZrC was hot pressed to near full density, sectioned to produce specimens for welding, and welded together to produce billets for mechanical property studies. The four-point flexure strength of the parent material was~660 MPa, while the strength of the welded specimens ranged from~140 to~250 MPa. Microstructural analysis revealed that decreased strength in the welded specimens was caused by volume flaws, microcracking of large ZrB2 grains (up to 1 mm in length), and residual tensile stresses that developed at the surface of weld pools during cooling. The versatility of plasma arc welding was demonstrated by joining of ZrC-based ceramics and fabricating three ZrB2-ZrC components for potential applications, including a high-temperature electrical contact, an ultra-high-temperature thermocouple, and a wedge that was a notional wing leading edge. These three applications demonstrated the ability to join ceramics to a refractory metal, fabricate a chemically inert high-temperature thermocouple, and produce complex shapes for aerospace applications.

Department(s)

Materials Science and Engineering

Keywords and Phrases

Aerospace applications; Carbides; Ceramic materials; Electric arc welding; High temperature applications; Mechanical properties; Plasma welding; Refractory metals; Strength of materials; Thermocouples; Welding; Zirconium compounds

International Standard Serial Number (ISSN)

1546-542X

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2016 Blackwell Publishing Ltd, All rights reserved.

Publication Date

01 Jan 2016

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