|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Ultrafine Grained Materials IX
||Twinning and Spall of Nanocrystalline Tantalum
||Eric Hahn, Diego Tramontina, Eduardo Bringa, Marc Meyers
|On-Site Speaker (Planned)
Shock deformation experiments and simulations allow us to investigate material strength and damage under extreme conditions. Strain-rates near a billion per second are of particular interest because constitutive responses of materials in this strain-rate regime are considerably less developed. Predictions based on traditional theory suggest that, as strain-rate increases, compressive and tensile strength should increase. Alternatively, as grain size decreases, tensile strength should decrease due to an increased propensity to fail at a growing volume fraction of grain boundaries. Recent predictions under compression using multiscale theoretical techniques suggest that grain size has a negligible effect on the ensuing plastic flow dynamics at such high strain rates. However, this model selectively disregards deformation twinning. Large-scale molecular dynamics simulations of bicrystals and nanocrystals are employed to investigate grain-size dependent twinning and tensile spall strength in tantalum, a model body-centered cubic metal.