Sinterbonding Cobalt-Cemented Tungsten Carbide to Tungsten Heavy Alloys

Abstract

Cobalt-cemented tungsten carbide (WC-Co) powder was sinterbonded to nickel-iron tungsten heavy alloy (WHA) for use in high-temperature tooling applications. Sinterbonding was performed under various conditions, including changes to the sintering conditions and initial WHA material forms, to determine various processing conditions that yield a consolidated interface indicative of a high degree of bonding. Sinterbonding WC-Co to fully dense WHA bar stock yielded a consolidated interface comprised primarily of complex η-carbides. Defects at the interface, including voids, microcracking, and porosity were the result of other sinterbonding processing conditions explored in this work. Co-rich η-carbides were found to form at the interface in every condition examined. A thermodynamic evaluation of η-carbides as a function of carbon activity determined that Co-rich η-carbides formed preferentially in regions of low carbon activity. The predicted thermodynamic trends are in agreement with interfacial microstructural observations.

Department(s)

Materials Science and Engineering

Sponsor(s)

Missouri University of Science and Technology. Intelligent Systems Center

Keywords and Phrases

Friction Stir Welding Tools; Sinterbonding; Tungsten Carbide; Tungsten Heavy Alloy; Η-Carbide

International Standard Serial Number (ISSN)

0263-4368

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2009 Elsevier, All rights reserved.

Publication Date

01 Sep 2009

Link to Full Text

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