Abstract
Ferrite steels exhibits ductile-brittle transition in general even in cases bearing the second phase. Low temperature brittle fracture mechanism in two cases of two-phase steels; one is two-phase stainless cast steel bearing ductile austenite grains and the other is pearlite steel bearing brittle cementite plates. Two-plane observations consisting of SEM fracture surface observation and Optical/SEM/EBSD observation on the sectioned and polished plane to reveal microstructure and crystallographic feature was performed. The role of the second phase particle for cleavage fracture of bcc grains is discussed.
