The problems encountered with the interpretation of martensite and the various forms of bainite that are found in high strength steel weld metals have been addressed. Field emission gun scanning electron microscopy was found to overcome resolution difficulties often met with light optical microscopy and conventional scanning electron microscopy. The various microstructural constituents were cha...

Bainite transformation behavior was monitored using simultaneous measurements of dilatometry and small angle neutron scattering (SANS). The volume fraction of bainitic ferrite was estimated from the SANS intensity, showing good agreement with the results of the dilatometry measurements. We propose a more advanced monitoring technique combining dilatometry, SANS and neutron diffraction.

It becomes possible in appropriate circumstances for similarly oriented plates of bainite or martensite to merge and form coarse crystallographically homogeneous domains whose presence leads to a deterioration in mechanical properties. A method is presented here for breaking up such domains, by introducing very small scale chemical composition variations in the austenite prior to its transforma...

The processing of advanced multiphase high strength steels often includes isothermal treatments around the martensite start temperature (Ms) for achieving a refined microstructure comprising bainite-austenite and/or bainite-martensite-austenite phase constituents. objective this research work was to investigate structure-property relationship medium carbon, high-silicon DIN 1.5025 steel (Fe-0.5...

In this study, two CCCT diagrams are drawn to be compared with a CCT diagram. The CCCT diagrams represent continuous cooling transformations in stress assisted state. The increased Md and Bd temperatures of CCCT diagrams were also compared with those of the CCT diagrams and the cause was investigated from both thermodynamic and metallurgical viewpoints. Thermodynamic examinations revealed that ...

Low-temperature bainite, obtained by the transformation of austenite at temperatures as low as 200oC for times as large as several days, has been reported to have extraordinary mechanical properties including the highest reported hardness of any bainitic steel. The unusual properties are a consequence of the fine scale of the microstructure, which contains bainite plates with thickness in the r...

structural steels with very high strength levels are often referred to as ultrahigh-strength steels (uhss). the usage of uhss has been extensively studied in aerospace industries and offshore platforms. in this study, medium carbon low alloy steel (ams6305) was thermomechanicaly treated to obtain an ultra-high strength bainitic steel for aircraft engine compressor disk. a novel themomechanical ...