An intrinsic ductility parameter derived from anisotropic linear elasticity theory

A new indicator of intrinsic ductility (x) is introduced based on linear elasticity. In the limit of elastic isotropy this parameter is equal to the Pugh ratio (BIG) plus a constant; but unlike the Pugh ratio, x incorporates anisotropy and crystallography to improve predictive value. We identify a single ductile-to-brittle transition setpoint for x that predicts crack-tip plasticity in atomistic simulations, experimental elongation to failure of polycrystalline elemental metals pulled in tension, and fracture energy measurements of glasses, suggesting commonality in the relationship between plasticity and fracture across all three of these cases. Statistical analysis supports the superiority of x over BIG at predicting crack-tip plasticity in atomistic simulations and elongation to failure of polycrystalline elemental metals.