EngD in Development of In-Process Machining NDE Approach to Predict Tool Wear and Titanium Component Microstructural Damage

This project sits within the Centre for Doctoral Training (CDT) in Advanced Metallic Systems - a distinct research centre formed by a partnership between the Universities of Sheffield and Manchester and the I-Form Advanced Manufacturing Centre, Dublin. Our doctoral students undertake a different doctoral programme, which includes a compulsory intensive technical and professional skills training programme throughout the 4-year project. For more information on our training programme content, aimed at converting graduates from a non-materials topic into metallurgy, please review our website (linked below).

This EngD project is based at the Department of Materials Science and Engineering at the University of Sheffield, and is sponsored by Seco Tools AB. We are seeking a candidate with a 2.1 or 1st class degree in a STEM discipline.

There is an increasing drive to reduce the cost of machining processes in the aerospace industry, partic-ulary in titanium and nickel-based superalloys. Such alloys are difficult to machine and there are com-plex interactions between the tool and substrate material that determines the wear rates, subsurface in-tegrity and ultimately component life (e.g. fatigue performance). The conventional approach to assess an alloy’s machinability is time-consuming and heavily material and machine intensive, thus expensive.

Over recent years the machining response of aerospace alloys was summarised through machinability maps (See figure for titanium alloys): to aid the machining supply chain in selecting feed rates and cut-ting speeds to generate certain chip forms, to extend tool life and minimise subsurface deformation for specific titanium alloys. Assessment of these key characteristics has provided an understanding of the effects of mechanical twinning on the poor chip control through increasing the accommodation of strain prior to fracture.

In this EngD project a key aim will be to (1) develop an in-process machining approach to monitor the structural health and underlying microstructure of either titanium alloy and nickel-based superalloy components produced by convention forging routes and emerging powder routes (such as FAST/SPS or AM), which generate a range of different microstructures and textures. Another aim will be to (2) measure in-situ temperature profiles at the cutting interface and determine the effects on microstructure and tool behaviour. The long term ambition is to develop a digital twin of the tool/workpiece interaction and reliably predict damage accumulation that could lead to poor mechanical performance in service.

During your PhD, you will develop core skills in machining science and metallurgy, such as microstructural characterisation, process metallurgy, FE modelling and data analytical approaches. You will work collaboratively with a broad range of engineers and researchers and have access to high performance manufacturing and characterisation facilities in the Henry Royce Institute and Seco Tools in both the UK (Alcester) and Sweden (Fagersta) – and thus, be expected to travel and spend a number of weeks in Sweden during the EngD. You will develop an insight into the technical advanced manufacturing challenges in the aerospace sector and work closely with the machining supply chain, including OEMs.

The project would suit a good Materials Science, Physics, Aerospace Engineering or Mechanical Engineering graduate with an interest in advanced manufacturing and digitisation of microstructure.

For more information please contact Professor Martin Jackson (martin.jackson@sheffield.ac.uk)