Howard Stone
Assistant Director of Research
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 materials capable of tolerating ever higher service temperatures. 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. After many years of research, continued improvements are still being achieved in the conditions that may be tolerated by these materials in service. My research is to develop our understanding of the relationship between the alloy composition, microstructure and properties, and how these are influenced by the processing and service conditions, in order to further improve the properties of these alloys and extend their lives in service.
Novel high-temperature materials
We are investigating novel materials that may provide viable alternatives to nickel-base superalloys in high-temperature applications such as aeroengines. 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 characterization of crystal structures in metals and alloys. With these methods, phase transformations are being studied on timescales of milliseconds and with very high resolution, providing unique insights into these processes.
- HJ Stone, TM Holden & RC Reed, "On the generation of microstrains during the plastic deformation of Waspaloy" Acta Mater. 47, 4435-4448 (1999).
- D Dye, HJ Stone & RC Reed, "Intergranular and interphase microstresses" Curr. Opin. Solid State Mater. Sci. 5, 31-37 (2001).
- HJ Stone, MG Tucker, FM Méducin, MT Dove, SAT Redfern, Y Le Godec & WG Marshall, "Temperature measurement in a Paris-Edinburgh cell by neutron resonance spectroscopy" J. Appl. Phys. 98, 064905 (2005).