Mechanism based mean-field modeling of the work-hardening behavior of dual-phase steels

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• 作者：F. Rieger^a ; ^{florian.rieger@kit.edu} ; M. Wenk^b ; ^{moritz.wenk@kit.edu} ; S. Schuster^c ; ^{simone.schuster@kit.edu} ; T. Bö ; hlke^a ; ^{thomas.boehlke@kit.edu}
• 关键词：Mean-field modeling ; Dual-phase steel ; Dislocation-density based modeling ; Long-range stresses
• 刊名：Materials Science and Engineering: A
• 出版年：2017
• 出版时间：13 January 2017
• 年：2017
• 卷：682
• 期：Complete
• 页码：126-138
• 全文大小：1918 K
• 卷排序：682

文摘

Low-alloyed dual-phase (DP) steels exhibit good mechanical properties due to their composite-like microstructure of strong martensitic inclusions embedded in a ductile ferritic-matrix. This work presents an efficient two-scale approach to model the work-hardening of DP steels based on physically-motivated work-hardening contributions from geometrically necessary dislocations. The resulting mean-field model of Hashin-Shtrikman type comprises a minimal amount of free parameters and incorporates two main physical aspects motivated from presented experimental data: First, the constitutive equations for ferrite incorporate the averaged microstructural morphology (obtained by electronic backscatter diffraction) in terms of grain size and martensite coverage. Second, a direct interaction between ferrite and martensite phases is achieved via kinematic-hardening which models the long-range stresses experimentally observed in tensile tests of the bulk material. The presented approach is able to both reproduce the measured DP600 tensile curve and predict the distinctly different work-hardening rates observed for high-strength DP steels.