Atomic-scale investigations of isothermally formed bainite microstructures in 51CrV4 spring steel

Atomic-scale investigation was performed on 51CrV4 steel, isothermally held at different temperatures within the bainitic temperature range. Transmission electron microscopy (TEM) analysis revealed three different morphologies: lower, upper, and inverse bainite. Atom Probe Tomography (APT) analysis of lower bainite revealed cementite...

In situ study on fracture behaviour of white etching layers formed on rails

Failure in engineering materials like steels is strongly affected by in-service deleterious alterations in their microstructure. White Etching Layers (WELs) are an example of such in-service alterations in the pearlitic microstructure at the rail surface. Cracks initiate in the rails due to delamination and fracture of these layers and...

High-resolution characterization of the martensite-austenite constituent in a carbide-free bainitic steel

The multiphase microstructure of carbide-free bainitic steels comprises bainitic ferrite laths, retained austenite with different morphologies, a minor fraction of carbides and so-called martensite-austenite areas, which partially transform during the last cooling step. While the other constituent received much attention, little is known...

Defect evolution during annealing of deformed FeSi alloys studied by positron annihilation spectroscopy

High silicon steel is widely used in electrical appliances. Alloying iron with silicon improves its magnetic performance. A silicon content up to 6.5 wt. % gives excellent magnetic properties such as high saturation magnetization, near zero magnetostriction and low iron loss in high frequencies. Their workability is greatly reduced by the...