A multiscale approach for the deformation mechanism in pearlite microstructure: Atomistic study of the role of the heterointerface on ductility

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

卷:598

Article

Shimokawa, Tomotsugu¹  Oguro, Takuma²  Tanaka, Masaki³  Higashida, Kenji³  Ohashi, Tetsuya⁴ 

[1] Kanazawa Univ, Sch Mech Engn, Kanazawa, Ishikawa 9201192, Japan

[2] Kanazawa Univ, Div Mech Sci & Engn, Kanazawa, Ishikawa 9201192, Japan

[3] Kyushu Univ, Dept Mat Sci & Engn, Fukuoka 8190395, Japan

[4] Kitami Inst Technol, Dept Mech Engn, Kitami, Hokkaido 0908507, Japan

关键词: Pearlitic steel;    Heterointerface;    Atomic simulation;    Mechanical property;    Ductility;    Cementite decomposition;   

DOI  :  10.1016/j.msea.2013.12.100

来源: Elsevier

【 摘 要 】

The role of the ferrite/cementite heterointerface on the mechanical properties of heavily-drawn-pearlitic steel is investigated via tensile deformation tests of multilayered composite models with brittle and ductile virtual materials in a two-dimensional triangle-lattice system by using molecular dynamics simulations. The interface strength is controlled by introducing a heterointerface potential. The dominant role of heterointerface on the mechanical properties of multilayered composite models is influenced by the interface strength. In case of weak interface strength, the heterointerface acts as a strong barrier to dislocation motion in the ductile phase; hence, the multilayered composite model shows high strength but extremely low ductility. This tendency corresponds well to that of as-drawn pearlitic steel with cementite decomposition. In case of strong interface strength, the heterointerface acts as a dislocation source of the brittle phase by dislocation transmission through the heterointerface from the ductile to brittle phase; hence, the multilayered composite model shows good ductility with a small decrease in strength. This tendency corresponds well to annealed pearlitic steel recovered from cementite decomposition. These results suggest that cementite decomposition decreases the plastic deformation potential of the heterointerface. The conditions necessary for the heterointerface to simultaneously exhibit high strength and ductility are discussed on the basis of the results of atomic simulations. (C) 2014 Elsevier B.V. All rights reserved.

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