Ductile to brittle transition temperature of functionally graded steels with crack arrester configuration

In the present study, ductile to brittle transition temperature of functionally graded steels has been evaluated by utilizing Charpy impact specimens with crack arrester configuration. Functionally graded steels which are composed of graded ferritic and austenitic regions together with bainite or martensite layer may be fabricated by electroslag remelting. For the specimens with the notches tip placed at graded ferritic region, the closer the notch tip to the bainite layer, the lower the transition temperature. For the specimens with the notches tip placed at graded austenitic region, no transition temperature was observed. It has been found that by situating a crack at bainite–ferrite while it propagates into graded austenitic region, no transition temperature is observed. On the other hand, a crack situated at austenite–bainite interface propagating into graded ferritic region experiences transition temperature.