Jaclyn Avallone, a Materials Ph.D. student, received a Gold Certificate in the Young Scientist Competition at the Ultrafine Grained Materials (UFG) IX Symposium at the 2016 TMS Conference.
Jaclyn is one of two Gold Certificate winners for best oral presentation. All of the students and post-docs who participated in the compeition were within three years of receiving their Ph.D. The award selection committe included the symposium organizers and invited speakers.
Jaclyn's presentation discussed how metallic multilayer systems are studied because of their promising performance in extreme environments. Properties are associated with the high density of bi-metallic interfaces, and therefore scale with the laminate layer thickness. Strength and resistance to damage by radiation or shock increase with decreasing length scale. The stability of the layered morphology at elevated temperature, however, has the opposite trend. It is necessary to determine how the creep properties of bulk metallic laminates vary with length scale in order to determine the optimal initial structure for use in high temperature structural applications.
She also described how Copper-Niobium is a model laminate system because these immiscible materials have sharp interfaces and roll-bond well due to similar flow stresses. Bulk metallic laminates, with initial layer thicknesses of nominally 2 micrometers down to 65 nanometers, are crept at 400℃. Preliminary results show that, unlike creep behavior in all other metallic systems, resistance to deformation improves with decreasing length scale. Initial microstructures and evolving stress states are discussed in relation to creep behavior.
The scope of the UFG IX Symposium focused on all aspects of science and technology of ultrafine grained (UFG) and nanocrystalline materials, ranging from fundamental science to applications of bulk ultrafine-grained (grain size <1000 nm) and nanostructured (feature size <100 nm) materials. The symposium provided a forum on the topics of fabrication and understanding of UFG and nanocrystalline materials including conventional and emerging technologies and advancements, fundamental issues in severe plastic deformation (SPD) processing and SPD-processed materials, UFG and nanocrystalline microstructure evolution, mechanical and physical properties, deformation mechanisms, superplasticity, joining and bonding, computational and analytical modeling, structural and functional applications, etc. Other emerging topics were covered include gradient and layered nanostructures, stability of nanostructured materials, powder processing and bio-inspired nanomaterials.