Critical stress prediction upon accurate dislocation core description

Existing approaches for friction (critical) stress determination are highly unsatisfactory because of empiricism associated with dislocation “core-width” and nature core-advance. This study, focusing on the a/2〈011〉 extended-dislocation (partials bounding a stacking-fault) in Face-Centered-Cubic (FCC) materials, rigorously derives core-width continuum strain-energy atomistic misfit-energy considerations. The is calculated using fully-anisotropic Eshelby-Stroh formalism accommodating inherent mixed characters a/6〈112〉 Shockley-partials constituting pure-edge/pure-screw dislocations. determined from critical fault-energies slip-plane input to novel misfit-model capturing lattice structure involving discrete Wigner-Seitz cell area at each site, advancing over an 80-year old model that has missed role both concepts. For first time literature, motion extended-dislocation's core derived optimized trajectory its total-energy. It shown partial's moves intermittently (“zig-zag” motion), not together, allowing stacking-fault width fluctuate during advance extended-dislocation. involve trajectory-dependent combination Schmid factors Shockley-partial, also revealed time. proposed used predict multiple FCC including high-entropy alloy (HEA), displaying excellent agreement experiments. work opens future avenues rapid reliable assessment multitude compositions across varying structures (e.g. hexagonal lattices), prior exponential models which can produce errors as high two orders magnitude.