|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||2016 Technical Division Student Poster Competition
||SPG-57: Strength Prediction in NiCo Alloys - The Role of Composition and Nanotwins
||Piyas Chowdhury, Huseyin Sehitoglu, Hans Maier, Richard Rateick
|On-Site Speaker (Planned)
Experimentally, tensile constitutive behaviors of nano-twinned Ni-Co alloys demonstrate the existence of a critical composition to achieve maximum strength. First, from ab initio calculations, we discover that the alloy gamma surface follows the same trend as a result of a competition between the solid solution hardening and the Suzuki segregation. Secondly, various slip-twin boundary interactions mechanisms are found to alter the alloy γ surface via molecular dynamics simulations. We compute the respective unstable stacking fault energies, which are then converted into frictional stresses within a Peierls-Nabarro modeling framework. Then, critical resolved shear stresses (CRSS) are predicted for different Ni-Co alloys, utilizing the first principle and the molecular dynamics results. In conclusion, the apparently puzzling trends in the Ni-Co macroscopic strengths are rationalized by considering the combined effects of: (a) the twin influenced slip activities at the mesoscale and (b) the alloying induced fault energetics at the quantum scale.
||Definite: None Selected