Research Focus

1. Structure–Composition-Magnetostriction Correlations in Strong and Ductile Fe-Based Alloys with Large Low-Field MagnetostrictionSivaraman Guruswamy, University of Utah, DMR 0854166 • Research Focus • Magnetostriction phenomenon refers to the change in the length of a material with applied magnetic field • Magnetostrictive materials are used in numerous sensor, actuator and energy harvesting (Wind/Ocean) applications. • Research examines how local atomic environment, crystalline structure and crystal defects influence the magnetostriction in a-Fe based alloys. Figure (top right) shows the Extended X-ray Absorption Fine Spectrum (EXAFS)* data (R) as a function of R and the fit from long-term annealed and quenched (LTA) Fe-15 at.% Ga single crystal. Data obtained at the Fe K edge. Data obtained on crystals with varying Ga contents and heat treatments. Near-neighbor distances measured indicate severe local lattice distortions. • Significant Findings • Controlling inhomogeneous elastic strains introduced by modifying local atomic spacing by solutes and defects, is key to controlling magnetostriction. • Controlled introduction of dislocations by deformation involving only a single slip system dramatically decreases the magnetostriction. Deformation involving multiple slip system leads to a much smaller decrease. Slip patterns Technical and Scientific Impact This is a significant contribution to a fundamental under-standing of magnetostriction. The work will help design alloys for sensor and actuators, energy harvesting, low-/zero-expansion structures, data storage media and other applications.

2. Structure–Composition-Magnetostriction Correlations in Strong and Ductile Fe-Based Alloys with Large Low-Field Magnetostriction Sivaraman Guruswamy, University of Utah, DMR 0854166 • Education, Training and Outreach • Graduate students Gavin Garside, Biswadeep Saha, Chai Ren and M. Ramanathan were trained in alloy synthesis, single crystal growth, XRD, magnetic measurements, SEM, and EXAFS analysis. • Chai Ren (2011) attended the Neutron and X-ray Scattering School at ORNL/ ANL. Gavin Garside graduated and is now employed at ATI-Wah Chang. • Graduate students presented 5 papers at TMS 2011 and will present 4 papers at TMS 2012. • Showcased the lab and research again to high school students, visitors and public during Science day, and Open House events held during 2011. Mr. Kent Rominger VP of ATK and former NASA Astronaut and Space Shuttle Commander with the PI and students at MML Graduate students Biswa-deep and M.Ramanathan preparing the alloy by arc- melting prior to single crystal growth. • Recognitions in 2011 • PI was recognized as an ASM Fellow in July, 2011 for his outstanding contributions to the development of Fe-Ga magnetostrictive alloys and cable sheathing alloys, and for his outstanding contribution to the education and mentoring of students. • PI mentored the student team that won the Materials Bowl held during TMS 2011 in San Diego. Two students form this research group (Biswadeep and M. Ramanathan) were members of the team. PI demonstrating an Fe-Ga magnetostrictive actuator based nano-positioning system to high school students and their parents during 2010 Science Day. Graduate students Gavin, Chai and Biswadeep being trained in the use of a Vibrating Sample Magnetometer system