An RVE procedure for micromechanical prediction of mechanical behavior of dual-phase steel

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:695

Article

Bong, Hyuk Jong¹  Lim, Hojun²  Lee, Myoung-Gyu³  Fullwood, David T.⁴  Homer, Eric R.⁴  Wagoner, Robert H.¹ 

[1] Ohio State Univ, Dept Mat Sci & Engn, 2041 Coll Rd, Columbus, OH 43210 USA

[2] Sandia Natl Labs, Dept Computat Mat & Data Sci, POB 5800, Albuquerque, NM 87185 USA

[3] Korea Univ, Dept Mat Sci & Engn, Seoul 02841, South Korea

[4] Brigham Young Univ, Dept Mech Engn, 435 CTB, Provo, UT 84602 USA

关键词: Crystal plasticity;    Dual phase steel;    Representative volume element;    Dislocation pile-up;    Superdislocation;   

DOI  :  10.1016/j.msea.2017.04.032

来源: Elsevier

【 摘 要 】

A bottom-up representative volume element (RVE) for a dual phase steel was constructed based on measured microstructural properties (microproperties). This differs from the common procedure of inferring hypothetical microproperties by fitting to macroscopic behavior using an assumed micro-to-macrolaw. The bottom-up approach allows the assessment of the law itself by comparing RVE-predicted mechanical behavior with independent macroscopic measurements, thus revealing the nature of the controlling micromechanisms. An RVE for DP980 steel was constructed using actual microproperties. Finite element (FE) simulations of elastic-plastic transitions were compared with independent loading-unloading-loading and compression-tension experiments. Constitutive models of three types were utilized: 1) a standard continuum model, 2) a standard Crystal Plasticity (CP) model, and 3) a SuperDislocation (SD) model similar to CP but including the elastic interactions of discrete dislocations. These comparisons led to following conclusions: 1) While a constitutive model that ignores elastic interaction of defects can be fit to macroscopic or microscopic behavior, it cannot represent both accurately, 2) Elastic interactions among dislocations are the predominant source of nonlinearity in the nominally-elastic region (i.e. at stresses below the standard yield stress), and 3) Continuum stress inhomogeneity arising from the hard martensite / soft ferrite microstructure has a minor role in the observed transitional nonlinearity in the absence of discrete dislocation interactions.

【 授权许可】

Free