Department of Materials Science & Metallurgy

Howard Stone

Howard Stone portrait

University Lecturer

MA University of Cambridge
PhD University of Cambridge

+44 (0)1223 334320
hjs1002@cam.ac.uk
www.msm.cam.ac.uk/UTC/

High-Temperature Materials

The ongoing drive for improved fuel efficiency and reduced emissions from gas-turbine aeroengines continues to demand new materials capable of tolerating ever higher service temperatures. At present, the majority of these applications are served by nickel-base superalloys, but new materials are now also being considered as potential successors to these alloys in many applications.

Nickel-base superalloys

The outstanding combination of properties of nickel-base superalloys has led to their widespread use in hot-section aeroengine components. By developing an improved understanding of the relationship between the alloy composition, microstructure and properties, and how these are influenced by the processing and service conditions, we are developing new alloys with superior properties than their predecessors.

Novel high-temperature materials

Novel materials that may provide viable alternatives to nickel-base superalloys in high-temperature applications such as aeroengines are also being investigated. While no material improves on conventional nickel-base superalloys in all regards, an understanding of the conditions that must be tolerated by individual components is leading to the identification and development of novel materials that may enable higher temperatures, stresses, longer lives or lighter components to be achieved.

In-situ characterization of phase transformations

Modern diffraction-based techniques using neutron and synchrotron sources such as the ISIS and ILL neutron sources and the European Synchrotron Radiation Facility offer powerful methods for the in-situ characterisation of crystal structures in metals and alloys. With these methods, phase transformations and deformation behaviour are being studied on timescales of milliseconds and with very high resolution, providing unique insights into these processes.

Reciprocal lattice point of a fundamental reflection from a fourth-generation single-crystal nickel-base superalloy obtained by synchrotron X-ray diffraction
Reciprocal lattice point of a fundamental reflection from a fourth-generation single-crystal nickel-base superalloy obtained by synchrotron X-ray diffraction
  • Bhowmik, A., Bennett, R.J., Monserrat, B., Conduit, G.J., Connor, L.D., Parker, J.E., Thompson, R.P., Jones, C.N., Stone, H.J., "Alloys based on Cr-Cr2Ta containing Si", Intermetallics, 48, pp. 62-70 (2014).
  • Bhowmik, A., Knowles, K.M., Stone, H.J. "Discontinuous precipitation of Co 3V in a complex Co-based alloy", Philosophical Magazine, 94 (8), pp. 752-763 (2014).
  • Collins, D.M., Stone, H.J., "A modelling approach to yield strength optimisation in a nickel-base superalloy", International Journal of Plasticity, 54, pp. 96-112 (2014).
  • Aveson, J.W., Tennant, P.A., Foss, B.J., Shollock, B.A., Stone, H.J., D'Souza, N., "On the origin of sliver defects in single crystal investment castings", Acta Materialia, 61 (14), pp. 5162-5171 (2013).