In-situ observation of microcrack evolution in a dual-phase steel during tensile straining

ABSTRACT

In this paper, the microcrack evolution in DP590 dual-phase steel was observed by in-situ straining in straining transmission electron microscopy. It was found that a void initiated ahead of a main crack. After the load was applied, a thinned area was nucleated ahead of the void tip, and it grew gradually into shallow nanovoid, penetrating nanovoid, and then new void. Meanwhile, the old void connected with the main crack. The repetitions of the procedures resulted in the continuous propagation of a crack. Interaction between microcracks was observed. The propagation direction of one microcrack may change, affected by other microcracks. Voids were observed between microcracks and have a significant effect on the coalescence of microcracks.

KEYWORDS:

• In-situ TEM
• dual-phase steel
• void
• microcrack
• propagation
• coalescence

Disclosure statement

No potential conflict of interest was reported by the author(s).

ORCID

Bin Chen http://orcid.org/0000-0001-9851-3928

Kaiyang Yin http://orcid.org/0000-0001-7149-2610

Additional information

Funding

This research is supported by open fund of the State Key Laboratory of Refractories and Metallurgy [grant number G201907], and National Natural Science Foundation of China [grant number 51971135].