複数の材料構成則を用いた結晶塑性解析による複相組織鋼の局所変形挙動評価

抄録

The demand for safety and reliability in pipelines has been increasing steadily. Dual-phase steels, especially with a bainite matrix and a well-dispersed martensite-austenite constituent (MA), provide ingredients necessary for the improvement of the yield ratio and toughness. To design alloy elements and ensure that dual-phase steels have the required mechanical properties, an understanding of the governing microscopic deformation mechanisms is essential. For this purpose, multi-constitutive crystal plasticity simulation coupled with local strain/stress partitioning, ductile damage and transformation-induced plasticity evolution was employed. Microstructural cell responses were captured by fast Fourier transform crystal plasticity analysis. Representative microstructural patches with the same high spatial resolution as those obtained by electron backscatter diffraction (EBSD) tomography provide new insights into the deformation mechanism in dual-phase microstructures, especially regarding the effects of the matrix and secondary phase distribution on the strain, ductile damage and transformation localization behavior.