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Powder Interlayer Bonding as a Novel Joining Technology for Next Generation Nickel-Based Superalloys for Aerospace Applications / OLIVIA STANNERS

Swansea University Author: OLIVIA STANNERS

  • E-Thesis – open access under embargo until: 12th April 2027

DOI (Published version): 10.23889/SUthesis.59838

Abstract

The purpose of this PhD project was to further develop the Powder Interlayer Bonding (PIB) technology that has been created at Swansea University. Previous work had focussed on using the technology for a range of titanium alloys for the aerospace industry. This PhD aimed to further its development b...

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Published: Swansea 2022
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
Supervisor: Davies, Helen M. ; Marchsio, Silvia
URI: https://cronfa.swan.ac.uk/Record/cronfa59838
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Abstract: The purpose of this PhD project was to further develop the Powder Interlayer Bonding (PIB) technology that has been created at Swansea University. Previous work had focussed on using the technology for a range of titanium alloys for the aerospace industry. This PhD aimed to further its development by investigating the technology’s feasibility for the joining of nickel-based superalloys. A next generation nickel-based superalloy was developed by Rolls-Royce plc and initial studies indicated it was difficult to join using traditional welding methods such as inertia friction welding. Therefore, it was of interest to investigate the feasibility of PIB for this alloy. PIB relies on a powder interlayer between two faying surfaces to reduce the effect of surface asperities and to aid the formation of a successful joint between two specimens. Initial results proved PIB to be a feasible joining technique for the next generation nickel-based superalloy and the range of parameters for successful bonding investigated. The microstructure of the alloy, both pre- and post-bonding, was analysed revealing a finer grained microstructure at the bonded region than the surrounding base material. In addition, the bondlines were found to have porosity levels lower than their surrounding base materials. Successfully bonded specimens underwent mechanical testing to explore their integrity. The tensile strengths of the bonds were below desired criteria of a repaired aerospace component, emphasising the need for post-bonding heat treatments on PIB next generation nickel-based superalloy and sufficient heating at the interlayer region during the PIB process to ensure consolidation of the powder. The final stages of the project involved undertaking preliminary work for PIB technology to be used to join nickel-based superalloys of dissimilar chemistries (Inconel 718, RR1000 and next generation nickel-based superalloy) with evidence of low porosity dissimilar bonds being attainable.
Keywords: nickel-based superalloys, aerospace alloys, powder interlayer bonding, joining, repair
College: College of Engineering