Abstract
In the present work, we clarify the fracture mechanisms in a dual-phase (DP) steel consisting of ∼75% martensite and exhibiting tensile strength of 1.5 GPa. Generally, the DP steels are considered resistant to brittle fracture due to the crack-arresting behavior of the ferrite. However, contrary to conventional wisdom, we report a predominant brittle fracture in the DP steel and clarify the associated damage mechanisms. Crack initiation occurs via martensite cracking along the prior austenite grain boundaries. The crack propagation in ferrite primarily occurs via {100} brittle cleavage cracking. Occasional void coalescence is also observed in ferrite. The brittle fracture observed in martensite is a mixed mode fracture consisting of both intergranular fracture and transgranular cleavage cracking along {110} planes. Furthermore, it is observed that the morphology of the martensite crack (sharp and blunt crack) influences ferrite cleavage cracking. The ferrite damage mechanisms associated with the sharp and blunt crack have been elucidated. Finally, the micro mechanism for the occasional ductile ferrite fracture has been explained.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
