Evaluation of local strength via microstructural quantification in a pearlitic rail steel deformed by simultaneous compression and torsion

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

卷:737

Article

Nikas, Dimitrios¹  Zhang, Xiaodan²  Ahlstrom, Johan¹ 

[1] Chalmers Univ Technol, Dept Ind & Mat Sci, Div Engn Mat, S-41296 Gothenburg, Sweden

[2] Tech Univ Denmark, Dept Mech Engn, Sect Mfg Engn, DK-2800 Lyngby, Denmark

关键词: Pearlitic rail steel;    TEM;    Hardness;    Strengthening mechanisms;    Dislocation density;   

DOI  :  10.1016/j.msea.2018.09.067

来源: Elsevier

【 摘 要 】

Pearlitic steels are commonly used for railway rails because they combine good strength and wear properties. During service, the passage of trains results in large accumulation of shear strains in the surface layer of the rail, sometimes leading to crack initiation. Knowledge of the material properties versus the shear strain in this layer is therefore important for fatigue life predictions. In this study, fully pearlitic R260 rail steel was deformed using a bi-axial torsion-compression machine to reach different shear strains. Microstructural parameters including interlamellar spacing, thickness of ferrite and cementite lamellae and dislocation density in the ferrite lamellae, as well as hardness were quantitatively characterized at different shear strain levels. Based on the microstructural observations and the quantification of the microstructural parameters, the local flow stresses were estimated based on boundary strengthening and dislocation strengthening models. A good agreement was found between the estimated flow stresses and the flow stresses determined from microhardness measurements.

【 授权许可】

Free