On key factors influencing ductile fractures of dual phase (DP) steels

X. Sun, K. S. Choi, A. Soulami, W. N. Liu, M. A. Khaleel

Research output: Contribution to journalArticlepeer-review

170 Scopus citations

Abstract

In this paper, we examine the key factors influencing ductile failure of various grades of dual phase (DP) steels using the microstructure-based modeling approach. Various microstructure-based finite element models are generated based on the actual microstructures of DP steels with different martensite volume fractions. These models are, then, used to investigate the influence of ductility of the constituent ferrite phase and also the influence of voids introduced in the ferrite phase on the overall ductility of DP steels. It is found that with volume fraction of martensite in the microstructure less than 15%, the overall ductility of the DP steels strongly depends on the ductility of the ferrite matrix, hence pre-existing micro-voids in the microstructure significantly reduce the overall ductility of the steel. When the volume fraction of martensite is above 15%, the pre-existing voids in the ferrite matrix does not significantly reduce the overall ductility of the DP steels, and the overall ductility is more influenced by the mechanical property disparity between the two phases. The applicability of the phase inhomogeneity driven ductile failure of DP steels is then discussed based on the obtained computational results for various grades of DP steels, and the experimentally obtained scanning electron microscopy (SEM) pictures of the corresponding grades of DP steels near fracture surface are used as evidence for result validations.

Original languageEnglish
Pages (from-to)140-149
Number of pages10
JournalMaterials Science and Engineering: A
Volume526
Issue number1-2
DOIs
StatePublished - Nov 25 2009
Externally publishedYes

Funding

Pacific Northwest National Laboratory is operated by Battelle Memorial Institute for the U.S. Department of Energy under Contract No. DE-AC05-76RL01830. This work was funded by the Department of Energy Office of FreedomCAR and Vehicle Technologies under the Automotive Lightweighting Materials Program managed by Dr. Joseph Carpenter. The authors would like to acknowledge the help of Mr. John Serkowski and Mr. Tao Fu for their help in generating the finite element mesh.

FundersFunder number
Department of Energy Office of FreedomCAR
U.S. Department of Energy
Battelle

    Keywords

    • Dual phases
    • Ductility
    • Finite element analysis (FEA)
    • Fracture
    • Phase inhomogeneity

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