Microstructure based prediction of strain hardening behavior of dual phase steels
Microstructure based prediction of strain hardening behavior of dual phase steels
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DOI：
10.1016/j.matdes.2012.05.010
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发表时间：
2012-10
影响因子：
8.4
通讯作者：
Sawitree Sodjit;V. Uthaisangsuk
中科院分区：
文献类型：
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作者：
Sawitree Sodjit;V. Uthaisangsuk
在汽车工业中，双相（DP）钢由于其高强度和良好成形性的优异组合而越来越多地用于各种车身部件。DP钢的显微组织基本上由嵌入马氏体岛的铁素体基体组成。马氏体相含量、形貌和相分布对双相钢的力学性能和断裂行为有重要影响。采用亚温退火工艺制备了不同马氏体含量的双相钢板。随后，提出了一种基于有限元（FE）的建模，使用代表性体积元（RVE）的方法来预测所研究的DP钢的整体应力-应变行为。从显微组织水平上的DP钢的显微照片生成二维RVE模型。对于单个单相流动曲线的基础上位错理论和当地的化学成分。此外，几何必要位错（GNDs），它积累在相边界处，由于淬火过程中的贝氏体-马氏体转变，被考虑在内。由于这些相界位错的局部硬化效应施加在铁素体和马氏体之间的界面层。DP钢的应力-应变响应的计算结果进行了验证，从拉伸试验确定的实验结果。然后，微观力学模型可以用来描述DP微观结构中的各个相的局部应力和应变演化。
In the automotive industries, dual phase (DP) steels have increasingly used for various car body parts due to their excellent combination of high strength and good formability. The microstructure of DP steel basically consists of a matrix of ferrite embedded by martensitic islands. For the mechanical and fracture behaviors of the DP steel, effects of martensite phase fraction, morphology, and phase distribution play an important role. In this work, dual phase steel sheets with different martensite contents were produced by intercritical annealing process. Subsequently, a Finite Element (FE) based modeling using Representative Volume Elements (RVEs) approach was proposed for predicting overall stress–strain behavior of the investigated DP steels. Two dimensional RVE models were generated from micrographs of the DP steels on the microstructure level. For the individual single phases flow curves based on dislocation theory and local chemical composition were applied. Additionally, Geometrically Necessary Dislocations (GNDs), which accumulates at the phase boundaries due to the austenite–martensite transformation during quenching process, was taken into account. A local hardening effect due to these phase boundary dislocations was applied at the interface layer between ferrite and martensite. The calculated stress–strain responses of the DP steels were verified with experimental results determined from tensile tests. The micromechanics model could be then used to describe the local stress and strain evolution of the individual phases in the DP microstructures.