Research Profile - Department of Materials Science and Metallurgy ...
Research Profile - Department of Materials Science and Metallurgy ...
Research Profile - Department of Materials Science and Metallurgy ...
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Howard Stone<br />
Assistant Director <strong>of</strong> <strong>Research</strong><br />
MA University <strong>of</strong> Cambridge<br />
PhD University <strong>of</strong> Cambridge<br />
+44 (0) 1223 334320<br />
hjs1002@cam.ac.uk<br />
www.msm.cam.ac.uk/utc/<br />
High-Temperature <strong>Materials</strong><br />
The ongoing drive for improved fuel efficiency <strong>and</strong> reduced<br />
emissions from gas-turbine aeroengines continues to dem<strong>and</strong><br />
materials capable <strong>of</strong> tolerating ever higher service temperatures.<br />
The majority <strong>of</strong> these applications are served by nickel-base<br />
superalloys, but new materials are now also being considered as<br />
potential successors to these alloys in many applications.<br />
Nickel-base superalloys<br />
The outst<strong>and</strong>ing combination <strong>of</strong> properties <strong>of</strong> nickel-base<br />
superalloys has led to their widespread use in hot-section<br />
aeroengine components. After many years <strong>of</strong> research, continued<br />
improvements are still being achieved in the conditions that<br />
may be tolerated by these materials in service. My research is to<br />
develop our underst<strong>and</strong>ing <strong>of</strong> the relationship between the alloy<br />
composition, microstructure <strong>and</strong> properties, <strong>and</strong> how these are<br />
influenced by the processing <strong>and</strong> service conditions, in order to<br />
further improve the properties <strong>of</strong> these alloys <strong>and</strong> extend their<br />
lives in service.<br />
Novel high-temperature materials<br />
We are investigating novel materials that may provide viable<br />
alternatives to nickel-base superalloys in high-temperature<br />
applications such as aeroengines. While no material improves<br />
on conventional nickel-base superalloys in all regards, an<br />
underst<strong>and</strong>ing <strong>of</strong> the conditions that must be tolerated by<br />
individual components is leading to the identification <strong>and</strong><br />
development <strong>of</strong> novel materials that may enable higher<br />
temperatures, stresses, longer lives or lighter components to be<br />
achieved.<br />
In-situ characterization <strong>of</strong> phase transformations<br />
Modern diffraction-based techniques using neutron <strong>and</strong><br />
synchrotron sources such as the ISIS <strong>and</strong> ILL neutron sources<br />
<strong>and</strong> the European Synchrotron Radiation Facility <strong>of</strong>fer powerful<br />
methods for the in-situ characterization <strong>of</strong> crystal structures in<br />
metals <strong>and</strong> alloys. With these methods, phase transformations<br />
are being studied on timescales <strong>of</strong> milliseconds <strong>and</strong> with very<br />
high resolution, providing unique insights into these processes.<br />
HJ Stone, TM Holden & RC Reed, “On the generation <strong>of</strong> microstrains<br />
during the plastic deformation <strong>of</strong> Waspaloy” Acta Mater. 47, 4435–4448<br />
(1999).<br />
D Dye, HJ Stone & RC Reed, “Intergranular <strong>and</strong> interphase microstresses”<br />
Curr. Opin. Solid State Mater. Sci. 5, 31–37 (2001).<br />
HJ Stone, MG Tucker, FM Méducin, MT Dove, SAT Redfern, Y Le Godec<br />
& WG Marshall, “Temperature measurement in a Paris-Edinburgh cell by<br />
neutron resonance spectroscopy” J. Appl. Phys. 98, 064905 (2005).<br />
Reciprocal lattice point <strong>of</strong> a fundamental reflection from a fourthgeneration<br />
single-crystal nickel-base superalloy obtained by<br />
synchrotron X-ray diffraction<br />
36 <strong>Research</strong> <strong>Pr<strong>of</strong>ile</strong>