Investigator: Dr Abigail Ackerman

Project Title:  Replicating Corrosion in Gas Turbine Engines

Supervisors: Dr Stella Pedrazzini

Corrosion is currently a significant problem within engineering. The corrosion of Ni superalloys in particular has been a large subject of study in recent years. The presence of SO_2/3 within gas turbine engines, as a product of exhaust emissions, volcanic activity and the ingestion and high temperature oxidation of H₂S is not yet understood. The production of SO₂, its conversion to SO₃ (with or without catalytic activity), the effect of moisture and/or salt on the materials within the turbine is known to be negative, but requires further investigation. This project involves the design and development of a novel gas exchange rig, that combines moisture and SO₂/SO₃ to replicate the service environment of a gas turbine engine. This is used in combination with salted specimens to perform fatigue tests at temperature in order to gain a more complete understanding of superalloy corrosion.

Investigator: Cynthia Rodenkirchen

Supervisor: Dr. Stella Pedrazzini and Prof. Mary Ryan

Collaborators: Rolls Royce

Duration: 28/02/2020 – 28/08/2023

Description:

Ni-based superalloys, commonly used e.g. in turbines for aircraft engines, are an important material class for operations at high temperature and high stress. They exhibit high mechanical strength and resistance to thermal creep deformation even at temperatures close to their melting points. Another essential characteristic of these superalloys is corrosion resistance. By investigation of several superalloys with varying Mo and W compositions, this study aims to understand the effect of Mo and W on type-2 hot corrosion of Ni-based superalloys.

Investigator: D R Clarke

Supervisors: Dr S. Pedrazzini (Primary), Dr B. Gault, Dr A. K. Ackerman

Collaborators: Rolls-Royce plc

Duration: 01/10/2019 – 01/10/2022 (PhD Studentship)

Abstract: The use of nickel-based superalloys for aerospace applications for turbine blades and discs is well documented, due to their high temperature mechanical properties and microstructural stability. One of the key challenges to their use is corrosion, which can be mitigated through the formation of a surface passivating, adherent oxide scale. Trace amounts of alloying elements effect the thermal probability for certain oxides to form. Utilising this phenomenon, a preferable compound oxide layer can be tailored to unique alloy operations. We will investigate the effects of certain elements on Ni-based superalloys, contributing to a multi-faceted investigation into reducing environmental degradation.

Investigator: Jessica Tjandra

Supervisor: Dr Stella Pedrazzini

Collaborator: Dr Enrique Alabort (Oxmet Technologies)

Duration: 27/09/2020 – 27/09/2024

Title: Corrosion in additively manufactured titanium alloys for biomedical applications

Description: Additively manufactured (AM) titanium alloys are increasingly used in biomedical applications, such as in bone replacements and joint implants. This project aims to understand the degradation mechanisms of AM titanium alloys when exposed to body fluid, under static exposure, corrosion wear and corrosion fatigue. Of particular interest is the effect of different AM lattices on the mechanical properties and material performance of these alloys.