How shear bands nucleate in metallic glasses
In plain words
Metallic glasses fail by concentrating all deformation into a thin band that then slides like a crack. How scattered local rearrangements organize into such a band, and at what strain, is unknown.
Precise statement
Determine the mechanism, length scale and critical strain for nucleation of a system-spanning shear band in metallic and model glasses under uniaxial or shear loading: the organization of shear-transformation zones (localized rearrangements of about 10 to 100 atoms) into a band, the role of local softening (free volume or effective temperature), and the resulting dependence of ductility on sample size and annealing.
What would settle it
A theory predicting the band nucleation strain and its sample-size and annealing dependence, confirmed by atomistic simulations and micro-pillar compression experiments.