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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Lindsay Greer<br />
Pr<strong>of</strong>essor <strong>of</strong> <strong>Materials</strong> <strong>Science</strong><br />
MA University <strong>of</strong> Cambridge<br />
PhD University <strong>of</strong> Cambridge<br />
+44 (0) 1223 334308<br />
alg13@cam.ac.uk<br />
www.msm.cam.ac.uk/mkg/<br />
Microstructural Kinetics<br />
My interest is in how materials change their structures.<br />
Underst<strong>and</strong>ing the mechanisms <strong>of</strong> these transformations is<br />
relevant not only for assessing the stability <strong>of</strong> materials, but also for<br />
developing new microstructures, properties <strong>and</strong> functionalities.<br />
Metallic glasses<br />
One route to new structures is to move further from equilibrium,<br />
<strong>and</strong> metallic glasses are a good example. Now that metallic<br />
glasses are available with minimum sections <strong>of</strong> the order <strong>of</strong> 1 cm,<br />
there is much interest in their mechanical properties, notably their<br />
exceptionally high strength, elastic strain <strong>and</strong> elastic energystorage<br />
capacity. We focus on the mechanisms <strong>of</strong> plastic flow<br />
under ambient conditions.<br />
Chalcogenides for data storage<br />
Chalcogenide alloys can be reversibly switched between glassy<br />
<strong>and</strong> crystalline states. This switching can be exploited in data<br />
storage, whether in DVDs or RAM. It is also <strong>of</strong> interest in cognitive<br />
computing. Our research, challenging because <strong>of</strong> the ultra-short<br />
switching times, focuses on maximizing data-storage density.<br />
Electromigration<br />
The migration <strong>of</strong> atoms when an electrical current flows in a<br />
material gives reliability problems in integrated circuits, but<br />
can also be used to develop novel structures. The competition<br />
between the effects <strong>of</strong> current <strong>and</strong> those <strong>of</strong> composition gradient<br />
(shown in the figure) is highlighted <strong>and</strong> exploited in our work.<br />
Phase nucleation<br />
Nucleation is the first step in phase transformations. Deliberate<br />
promotion <strong>of</strong> nucleation, whether in industrial processing such as<br />
the grain refinement <strong>of</strong> aluminium, or the control <strong>of</strong> ice formation<br />
by living systems, remains imperfectly understood, but our recent<br />
work shows that the nucleation kinetics can be quantitatively<br />
predicted.<br />
TE Quested & AL Greer, “Athermal heterogeneous nucleation <strong>of</strong><br />
solidification” Acta Mater. 53, 2683–2692 (2005).<br />
AL Greer & ND Mathur, “<strong>Materials</strong> science: Changing face <strong>of</strong> the<br />
chameleon” Nature 437, 1246–1247 (2005).<br />
JJ Lew<strong>and</strong>owski & AL Greer, “Temperature rise at shear b<strong>and</strong>s in metallic<br />
glasses” Nature Mater. 5, 15–18 (2006).<br />
HT Orchard & AL Greer, “Electromigration effects on intermetallic growth at<br />
wire-bond interfaces” J. Electron. Mater. 35, 1961–1968 (2007).<br />
Theoretical survey <strong>of</strong> how imposed electrical currents can<br />
dramatically influence the growth <strong>of</strong> intermetallic layers at<br />
bimetallic junctions<br />
22 <strong>Research</strong> <strong>Pr<strong>of</strong>ile</strong>