Serration Statistics in the stress versus strain curves of Bulk Metallic Glasses: comparing high time-resolution experiments to a simple model
Wendelin Wright (Bucknell University), Rachel Byer (Bucknell University), Xiaojun Gu (Bucknell University), Todd Hufnagel (Johns Hopkins University), James Antonaglia (University of Illinois at Urbana Champaign), Jonathan Uhl (), Karin Dahmen (University of Illinois)
Slip Avalanches in Amorphous Metals
Mon 9:00 - 10:30
Barus-Holley 168
Ductile bulk metallic glasses are known to deform intermittently with slip-avalanches detected as serrations in the stress-strain curves. In many such materials, power laws govern the statistics of these avalanches. Quasi-static compression tests were performed on a ductile Zr45Hf12Nb5Cu15.4Ni12.6Al10 bulk metallic glass. A piezoelectric load cell was used to observe the serrated flow at a data acquisition rate of 100 kHz in a high stiffness, precisely aligned load train. This high time-resolution, low-noise data is compared with predictions from a basic micromechanical model for deformation of solids with only one tuning parameter (weakening ). The model predicts the observed stress-strain curves, acoustic emissions, related power spectra, and power-law statistics of slip avalanches, including the dependence of the cutoff on experimental parameters, such as shear rate and temperature, with a continuous phase transition from ductile to brittle behavior. Material-independent (“universal”) predictions for the power-law exponents and scaling functions are extracted using the mean-field theory and renormalization group tools. WJW and XG were funded by NSF grant DMR-1042734, TH was funded by NSF DMR-1107838, JA and KAD were funded by NSF grant DMR-1005209.