CONTROL OF KINETIC PROCESSES IN IRRADIATED ALLOYS THROUGH COMPOSITIONAL PATTERNINGPascal Bellon, University of Illinois at Urbana-Champaign, DMR 0804615 Intellectual Merit The project aims at developing nanostructures that display high stability at elevated temperature and under prolonged irradiation. This goal is pursued by investigating model ternary alloys using experiments on thin films and atomistic computer simulations. A new nanostructuring pathway has been discovered by employing highly immiscible alloying elements that are also slow diffusers in the alloy matrix (e.g. W in Cu). • These solute atoms can deplete the matrix of other solute atoms, leading to the refinement of pre-existing precipitates and bimodal size distribution (see figure). • The resulting nanostructures are stable at very high homologous temperatures, up to 80% of the melting point in Cu88Nb10.5W1.5. (a) (b) (c) Evolution of precipitate size in ternary alloys: (a) KMC simulations; (b) experiments in Cu-Nb-W. The resulting nanostructures display bimodal size distribution (c) and high resistance to coarsening.
CONTROL OF KINETIC PROCESSES IN IRRADIATED ALLOYS THROUGH COMPOSITIONAL PATTERNINGPascal Bellon, University of Illinois at Urbana-Champaign, DMR 0804615 • Broader Impacts • Integrating research and education • Two undergraduate students have been mentored by the grant graduate students and the PIs in summer 2010. • Disseminating research and promoting science • • RS Averback lectured at the summer school “Atomic-response of materials to irradiation” in Sante Fe, NM (June 2010). • • RS Averback introduced research on self-organization in nonequilibrium materials to practicing engineers at ASM chapter meeting, in Peoria, IL (March 2010). • • P Bellon has served as the president of the scientific committees of international irradiation plate-forms JANNuS and EMIR (France), organizing the review of 60 proposals. • • The PIs have promoted the field of Materials Science and Engineering by giving presentations to high school students during Science Olympiads, and to incoming female freshmen. Undergraduate students Tiffany Ngan (left) and Michael Campion (right) with graduate student Xuan Zhang preparing for an irradiation experiment Summer school on “Atomic-response of materials to irradiation”, Sante Fe, NM, June 2010.