Evaluation of local strength via microstructural quantification in a pearlitic rail steel deformed by simultaneous compression and torsion
Artikel i vetenskaplig tidskrift, 2018

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.

Pearlitic rail steel

Hardness

Strengthening mechanisms

Dislocation density

TEM

Författare

Dimitrios Nikas

Chalmers, Industri- och materialvetenskap, Konstruktionsmaterial

X. Zhang

Danmarks Tekniske Universitet (DTU)

Johan Ahlström

Chalmers, Industri- och materialvetenskap, Konstruktionsmaterial

Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing

0921-5093 (ISSN)

Vol. 737 341-347

Ämneskategorier

Teknisk mekanik

Annan materialteknik

Metallurgi och metalliska material

DOI

10.1016/j.msea.2018.09.067

Mer information

Senast uppdaterat

2018-10-02