Dr Oliver Hatt
Position
Research Associate
Funding body
Manufacturing with Advanced Powder Processes (MAPP)
Dr Oliver Hatt, after obtaining a First-Class degree in Chemistry, initially pursued a mechanical engineering career with the AMRC with Boeing before undertaking his PhD at the University of Sheffield. His research centered on titanium alloy machining, with a specific focus on the interactions at the tool-workpiece interface underpinned by alloy and tool design.
Dr Hatt employed high-resolution electron microscopy techniques such as TEM and FIB, alongside thermodynamic modelling using Thermo-Calc, DICTRA, and TC-Prisma. Currently, he is involved in the design and development of new materials for gas turbines as part of the EPSRC ‘Designing alloys for resource efficiency (DARE) – a manufacturing approach’ partnership.
This collaborative initiative includes the University of Sheffield, Imperial College London, Kings College London, and the University of Cambridge, along with ten industrial partners, including Timet, Rolls-Royce, Tata Steel, and Siemens.
Past Research Focus
The aerospace industry spends hundreds of millions of dollars on the machining of titanium alloy components and with increasing aircraft orders, there is pressure to machine at higher production rates and develop more machinable alloys (e.g. TIMETAL® 54M, TMETAL® 407) without compromising titanium’s excellent mechanical properties.
Increasing the tool life by a factor of minutes can have a dramatic effect on machining cost. Unlike steels, the same tool grade is used for all titanium alloy types from alpha to beta rich, with the latter being more difficult to machine. Diffusion dominated crater wear is the primary tool wear phenomena which has yet to be fully understood.
Dr Hatt's research investigated the application of a low-cost diffusion couple technique which gives a strong indication of the complex reaction mechanisms occurring at the tool-chip interface during the machining of titanium alloys. These small-scale tests have been validated with large scale dynamic machining trials and strong agreement has been observed. Such a testing regime can be incorporated into alloy design approaches to inform the industry e.g. TIMET and Rolls-Royce about the ‘machinability’ qualities at a much earlier stage before costly machining trials. Such a method will also aid tool manufacturers to tailor tool carbide grades as well as new coatings to specific alloy chemistries.
