Speaker: Mark Croft, Rutgers University, Dept. of Physics & Astronomy
Date & Time: October 28, 2008 - 1:30pm
Location: Room 385E Serin Physics Lab
New insights into fatigue cracking, strain localization, and real battery electrochemistry from in situ high energy x-ray diffraction.
Physics and Astronomy
Mark Croft, Rutgers University, Dept. of Physics & Astronomy
1:30 PM, Room 385E Serin Physics Lab
High energy (30-180 keV), synchrotron based, energy dispersive x-ray diffraction (EDXRD) offers the opportunity to study a host of problems deep in bulk materials with high spatial resolution. The bulk penetrating power of the technique is illustrated by its ability to map strain variations (at the 10-5 level) deep within 2 inch thick steel specimens. The high spatial resolution allows mapping of crystalline phases and strain field variations on length like scales as low as 1-50 microns. These capabilities open a microscopic experimental window on a host of phenomena heretofore totally inaccessible. Illustrative applications of EDXRD to a series of materials/engineering problems will be discussed. Unique results on the strain fields involved in fatigue cracking, in stress gradient induced strain localization and in large elasto-plastic bending deformations will be presented. In addition spatial/temporal crystalline phase mapping of the detailed electrochemistry in real commercial size batteries will be discussed.