Dynamic meshing force and blunt effects on atomistic scale ductile-brittle behavior of the crack in bcc iron

This work investigates the dynamic meshing force and blunt effects on atomistic scale ductile-brittle behavior of the crack in bcc iron through molecular dynamics. Two engineering factors including upload ratio and contact ratio are introduced to reveal the effects of force amplitude and distribution. Under different upload and contact ratios, normal stress fields are diverse and crack can propagate in ductile-to-brittle, weak ductile, and strong ductile ways. The increase of blunt layer leads to modest increase in critical applied load for crack ductile propagation, but it leads to obvious enhancement of crack toughness during single-tooth meshing.