Ductile-to-Brittle transition in 〈111〉 hadfield steel single crystals

Abstract

The deformation mechanism and the character of fracture of 〈111〉 austenitic Hadfield steel single crystals are studied during tension in the temperature range 77–673 K by scanning and transmission electron microscopy. It is found that a change in the fracture mechanism from ductile to brittle fracture according to the fractography criterion takes place at a higher temperature than that determined from a change in the elongation to failure of the single crystals. The ductile-to-brittle transition in the Hadfield steel single crystals is shown to be related to a high level of deforming stresses induced by solid-solution hardening and to mechanical twinning.