High Temperature Materials
The drive for improvements in the environmental performance of aeroengines requires the development, characterisation and processing of new materials. For power plants the key drivers are:
- Increased operating temperatures and efficiency
- Improved reliability and availability
- Reduced unit and operating costs
The School of Materials is already making a major contribution in these areas, and is well placed to provide the research basis for a number of emerging technologies.
High Temperature Materials Research at the University of Manchester
High Temperature Protection
This multidisciplinary area, encompassing high-temperature corrosion, erosion-corrosion and wear protection, focuses on the role of oxide scales in the protection of high-temperature alloys, composites, ceramics and coatings. Mechanisms of growth, protective properties, and breakdown in aggressive conditions, including complex, impure environments, with very high temperatures and external stresses, have been determined. These are relevant to waste-to-energy systems, petrochemical plant, gas turbines, metals extraction and processing plant, and clean coal power technologies. Use of realistic test and simulation facilities, with electron-optical and surface-analytical probing, has allowed scientific underpinning of the selection of materials and corrosion-management criteria for efficient and environmentally-friendly industrial processes. The Group's expertise is also directed at development of surface coatings for materials protection under very hostile conditions. A detailed scientific understanding of the degradation mechanisms for furnace lining refractories has led to development of methods of laser treatment for improved protection; there is increased understanding of the role of oxide scales on adhesion of thermal barrier coatings to turbine alloys as well as materials solutions to metal dusting in advanced petrochemical plant.
Currently active research areas include:
- High-Temperature Degradation and Protection
- Laser Surface Engineering
- Corrosion Control in Light Alloys
Advanced Friction Joining
The exploitation of the next generation of superalloys and Ti alloys into more efficient designs requires the exploitation of inertia and linear friction welding. Through our links with Rolls-Royce we are a world leader in this area. We have a particular interest in managing residual stresses in such welds and understanding the effect of welding parameters through detailed mirostructral mapping across the weld line. In addition, we have developed experimental techniques using non-contact 2D strain mapping techniques to obtain the stress-strain response for various positons across the weld line.
Ti-Sic Fibre Composites
In collaboration with Birmingham University we are able to undertake unique research into the micromechanics of Ti/SiC composites and components. In particular we can determine the performance of the key Ti SiC interface.
Net Shape Powder Hipping
Currently we are providing non destructive information about the extent of consolidation during HIPping as well as precise 3D information about the conformance of the HIPped product to the original shape.
Laser Peening and Low Plasticity Burnishing/Deep Rolling
We are researching the effect of these new surface processing technologies for the extension of fatigue and predicting fatigue lives of discs and blades. Furthermore we are the preferred supplier to Rolls-Royce and other aerospace companies of residual stress measurements introduced by these processing treatments. Metals Improvements Company in Earby is a key collaborator.
Advanced Microstrucutural and Texture Characterisation
We have a great deal of expertise in microstructural characterisation by transmission and scanning electron microscopy of high temperature materials such as particle (?') strengthened nickel base superalloys, Ti alloys and TiAl intermetallics, all key materials for the next generation of engines. In particular the application of advanced scanning electron microscopy, i.e. high resolution imaging and EBSD for microstructural mapping is of great importance to study microstructural homogeneity and variations across weld regions. EBSD has become the dominant tool for characterising texture of a material on the macro and microscale.
Deformation mechanisms
We are researching the effect of microstructure in nickel-base superalloys and hcp materials such as Ti alloys on deformation mechanisms using advanced in-situ experimental techniques in combination with plasticity modeling. Here, neutron and high energy synchrotron x-ray diffraction allows us to study slip modes while we deform the material. The interpretation of the results requires plasticity modeling such as crystal plasticity finite element modeling and post mortem analysis of the dislocation structures using electron microscopy. This work is funded by the EPSRC and MoD and supported by Rolls-Royce.
Laser Peening
Laser peening is a new technique able to prolongate fatigue lives of critical components in excess of 10x. This technique has been so successful that Metal Improvements Company have set up a dedicated facility to treat fan blades and discs in the North West. We collaborate with Rolls-Royce and Metal Improvements Company to ensure that the blades are treated to the prescribed standard.
Residual Stress and Microstructural Development During Welding
The heat associated with welding technologies can cause significant residual stresses and microstructural changes. Our work has been instrumental in identifying effective post weld treatment procedures which retain favourable microstructures but are sufficient to relieve residual stresses to safe levels for a wide range of innovative joining technologies.
Intermetallics
Intermetallics offer unrivalled potential for the elevation of operating temperature of metallic parts in aeroengines. While they have excellent high temperature strength, room temperature toughness and fatigue resistence remain problem areas, with early onset of micro-cracking. It is believed that one answer is to engineer the best microstructures. In collaboration with Birmingham University we are aiming;
- to define the level of internal stress generated during deformation of TiAl-based alloys in order to increase our understanding of the observed pre-yield cracking in these alloys,
- to determine the level of microplasticity in relation to the orientation of the lamellar colonies and the role of any gamma grains in TiAl-based alloys before pre-yield cracking occurs,
- to use this knowledge to design optimised microstructures in plastically anisotropic materials.
High Temperature Materials Facilities at the University of Manchester
X-Ray Stress Measurement Facility
The Unit for Stress and Damage Characterisation in the School of Materials is the pre-eminent Centre in the UK for residual stress measurement. It is a partner in the Rolls-Royce Materials UTP along with Birmingham, Cambridge, Cranfield, Oxford and Swansea. In particular it supports the fan blade development programme at Barnoldswick and the friction joining projects at Ammersley, Nottingham. Commercially, it is the Rolls-Royce preferred supplier for stress measurement and has made measurements for over 30 other companies. The facility has 15 pieces of state of the art stress and damage measurement equipment; more than anywhere else in the world.
Postgraduate Study in High Temperature Materials
Taught programmes; Corrosion Control Engineering
The masters programme in Corrosion Control Engineering provides you with a thorough grounding in corrosion and its control. You will explore principles, protection strategies, and industrial applications, preparing you for either a career in industry as a corrosion scientist or engineer, or for cutting-edge academic research.
Research Degrees
Student research degrees in Metallic Materials are based within a vibrant research group, which is one of the largest in the UK. The research encompasses all aspects of metals alloys and composites, including their design, processing, forming, joining and performance.
Research Focus
The research extends from fundamental science, and the blue skies development of novel technologies and techniques, to the very applied, with the aim of improving our understanding of the basic governing principles, process simulation and physical modelling. While our research is broad ranging, one particular focus is on high-temperature materials for aeroengines and power generation.
| Name | Research Areas |
|---|---|
| Dr D Hall | High temperature piezoelectric ceramics |
| Dr Z Liu | High-temperature degradation and protection |
| Professor M Preuss | Residual stresses, microstructure and mechanical properties in high temperature materials (FULL) |
| Dr J Quinta da Fonseca | Crystal plasticity modelling, non-contact 2D strain mapping, mechanical properties/deformation mechanisms |
| Professor P Skeldon | High-temperature degradation and protection (I) |
| Dr P Xiao | Ceramic coatings with enhanced performance at high temperature (FULL) |
| Professor P Withers | Residual Stress and Damage Characterisation (F) |
