|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Mechanical Behavior of Nanostructured Materials
||Strength and Deformation of Far-from-Equilibrium Metallic Systems at the Nano-scale: High-Entropy Alloys and Metallic Glasses
||Julia R Greer, Rachel Liontas, Adenike Giwa, H. Diao, Peter Liaw
|On-Site Speaker (Planned)
||Julia R Greer
High entropy alloys represent a material class characterized by cubic-like thermally-stable solid solution phases. We fabricated nano-sized pillars with diameters between 400nm and 5microns contained within individual phases of Al0.7CoCrFeNi. We present orientation and phase mapping along with uniaxial compression results for each phase. Results show that samples BCC-like phase (A2+B2) exhibit high strengths of ~3 GPa, smooth stress-strain data, and significant hardening. Samples from FCC-like phase have discrete strain bursts, a lack of global hardening, and relatively high strengths, a signature of single-crystalline nano-plasticity.
We also investigated mechanical behavior and atomic structure of sputtered glassy Zr-Ni-Al nanopillars with widths of 75-215 nm. In-situ tensile tests conducted inside SEM reveal extreme ductility in metallic glass nanopillars, reaching >150% true plastic strains, and necking down to a point. Using MD simulations, TEM, and synchrotron XRD, we explain the observed mechanical behavior through changes in free volume and short-range order.
||Planned: Supplemental Proceedings volume