Effect of microstructural refinement on the toughness of low carbon martensitic steel

The ductile to brittle transition temperature of a commercial martensitic steel decreases with the refinement of its microstructure. Electron backscattered diffraction analysis of the cleavage crack path shows that the packet boundaries can strongly hinder fracture propagation, and thus martensitic packets can act as the effective microstructure unit for cleavage. (C) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.