Development of hybrid advanced manufacturing FAST-forge route for next generation aerospace components

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Over recent years, researchers at The University of Sheffield have developed a hybrid solid-state processing route that converts titanium alloy powder into fully dense parts in two steps. Step 1 exploits the rapid sintering process - field-assisted sintering technology (FAST) to consolidate a range of titanium powder and particulates. FAST is different from conventional sintering methods as a current flows through the powder to achieve a Joule heating effect instead of using an external heat source. The team have demonstrated the consolidation of powders such as PREP, HDH, GA and machined swarf of a range of titanium alloy chemistries. The process produces densities comparable to hot isostatic pressing (HIP), however the advantages of FAST include consolidation times of up to 1 hour (as opposed to 4 hours in HIPing) and shaped preforms without the need for canning. Step 2; researchers at Sheffield have exploited the benefits of FAST to be an intermediate process for a subsequent one step forging stage to provide enhanced mechanical properties. FAST-forge is now being exploited for small to medium sized titanium alloy landing gear components.The benefits of FAST as a solid state diffusion bonding technique for powder have recently been realised (known as FAST-DB). Rolls-Royce titanium alloy and nickel superalloy powders have been successfully bonded using such a solid state technique. Potentially FAST-DB can be developed into a manufacturing route that can provide components with multi-alloy regions, for example to enhance creep and fatigue resistance in key subcomponent regions, ultimately increasing the life of aerospace components. The aim of this EngD is to exploit and further understand the characteristics of the FAST-DB and FAST-forge for aerospace alloy powders. The aim is to use ThermoCalc, DEFORM and COMSOL software to produce predictive models for industrial scale FAST derived components. An example of a key demonstrator component could be a compressor blade where different titanium alloys may be used for the aerofoil and dovetail. The project aligns with the large scale equipment earmarked for the Henry Royce Institute and objectives of the EPSRC Future Manufacturing Hub MAPP (Manufacture using Advanced Powder Processes). The objectives at the end of the project will be to transfer the knowledge to the High Value Catapult Centres for large scale exploitation into industry.Through the EngD you will be gain valuable and career defining experience in titanium and/or nickel superalloy metallurgy, process modelling, FAST, thermomechanical processing, mechanical testing, a range of characterisation techniques (electron microscopy, XRD), finite element modelling (DEFORM), physics-based modelling (COMSOL) and thermodynamic modelling (ThermoCalc). You will be expected to present results to Rolls-Royce on a weekly basis and engage with their materials and process modelling teams