April 18-19, 2005

Strain-Mapping Workshop Marked by Enthusiasm and Idea-Sharing

Useful, lively discussions characterized the recent workshop on Strain Mapping in Engineering Materials with High-Energy Synchrotron X-Rays, held at the NSLS from April 18-19. The workshop brought together researchers in the field of strain mapping to discuss their work and talk about how to advance NSLS strain-mapping capabilities. Some of the talks are summarized below.

Participants of the Strain-Mapping workshop.

Asuri Vasudevan, from the U.S. Navy's Office of Naval Research, discussed how he works to extend and predict the life of aircraft and helicopters by studying "residual stresses" - the stresses within a material left over after a single or repeated use, which are caused by temperature or the material's chemical environment. Residual stresses can cause cracks on surfaces that may be stable or unstable. Vasudevan is interested in studying these cracks, but said that the tools available to him limit the size of the crack he can study as well as the sample's thickness and particular composition.

Mel Roquemore and Ruth Sikorski from the Air Force Research Laboratory addressed the potential applications of strain mapping to evaluate jet engine components. Their aims include using the determined stresses that occur within the engine components to predict and model how complicated engine systems will respond to duty-cycle loading. This information will help them determine how to increase the life of engine components.

Another key speaker was Roger Klaffky, who runs the X-Ray and Neutron Scattering Facilities program within the U.S. Department of Energy's Office of Science. He spoke about the DOE's mission to advance nanoscience research for energy needs, and the advantages of x-ray diffraction in this respect. He also gave examples of current stress/strain research now being done at DOE national labs, such as studying why fractures occur over time in stents and how that process may be stunted.

Additionally, an overview of the NSLS beamlines and user community was presented by NSLS scientist Chi-Chang Kao. He laid out the NSLS three-to-five year plan, which aims to continue the growth of life and geo/environmental science user groups, and attempt to reverse the decline in materials and chemical science users. Other initiatives are to advance the biomedical imaging program here and develop a new nanoscience user base. But in the area of strain mapping using high-energy x-rays, Kao said the NSLS needs to win funding for a new end station dedicated solely to that field.

The scheduled discussion period at the end of the workshop, and the several smaller discussions in between, produced many ideas and ways to bolster the strain-mapping program at the NSLS. The participants compiled a "wishlist" of capabilities they would like to see at X17B1, which is where strain-mapping research is now performed, and described current limitations to their research. For example, they discussed how to decrease the time it takes to make a strain map, which is one limitation may now prevent industrial users from coming to the NSLS.

The group also talked about potential future beamline X17A, which could free up X17B1 to become a strain-mapping-only beamline. Currently, high-energy x-ray scattering and medical researchers share the limited beamtime at X17B1 with scientists in the strain-mapping program.

RELATED LINKS: Workshop Website

ARTICLE BY: Laura Mgrdichian

PHOTO BY: Roger Stoutenburgh