Yadong Zhou, Kegu Lu, Redmer van Tijum, Maysam Naghinejad, Yutao Pei, Jan Post
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引用次数: 0
Abstract
This work investigates microscale strain localization and slip activity in ferritic AISI 420 stainless steel using an integrated approach of scanning electron microscopy-based digital image correlation (SEM-DIC), electron backscatter diffraction (EBSD), and crystal plasticity (CP) modeling. A novel aspect of this study is the direct coupling of multi-step SEM-DIC with CP modeling to link experimental strain fields with simulated slip activity. The microstructure, consisting of ferritic grains with finely dispersed carbides, exhibits early strain localization that intensifies under increasing global strain, ultimately forming interconnected shear bands. Statistical analyses indicate that localized deformation does not arise from any single microstructural parameter, such as grain size, grain boundary misorientation, maximum Schmid factor, or carbides’ effect, but rather from the combined influence of multiple constraints. Specifically, poor geometrical alignment of slip transfer at misaligned grain boundaries, restricted slip paths between ferrite grain boundaries and carbides, and limited deformation accommodation in smaller grains collectively promote strain localization. To further analyze slip transfer conditions, an accumulated-shear methodology is introduced to identify the dominant slip systems by integrating the loading history from multi-step DIC measurements, thereby enabling direct comparison with the corresponding CP-modeled variables. This method overcomes the transient limitations of velocity-gradient-based methods and provides a more reliable means of evaluating slip activity. Additionally, a CP model based on the DIC region of interest (ROI) microstructure reveals local stress heterogeneities at the microscale. This work offers insights into the mechanisms of microscale strain localization in ferritic stainless steel and highlights the critical role of microstructural features in triggering local deformation behavior.
期刊介绍:
The International Journal of Mechanical Sciences (IJMS) serves as a global platform for the publication and dissemination of original research that contributes to a deeper scientific understanding of the fundamental disciplines within mechanical, civil, and material engineering.
The primary focus of IJMS is to showcase innovative and ground-breaking work that utilizes analytical and computational modeling techniques, such as Finite Element Method (FEM), Boundary Element Method (BEM), and mesh-free methods, among others. These modeling methods are applied to diverse fields including rigid-body mechanics (e.g., dynamics, vibration, stability), structural mechanics, metal forming, advanced materials (e.g., metals, composites, cellular, smart) behavior and applications, impact mechanics, strain localization, and other nonlinear effects (e.g., large deflections, plasticity, fracture).
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