There are important aspects of steel which are hidden from ordinary view and largely from the users of steels. They nevertheless determine the macroscopic behaviour. One example is that the magnetic properties of austenite determine that it has a larger thermal expansion coefficient than ferrite, whereas intuition would suggest otherwise given that austenite has a greater density. This and othe...

Developing numerical methods for predicting microstructure in materials is a large and important research area. Two examples of material microstructures are Austenite and Martensite. Austenite is a microscopic phase with simple crystallographic structure while Martensite is one with a more complex structure. One important task in materials science is the development of numerical procedures whic...

Data about an effect of cyclic γ-α-γ martensitic transformations on the structure state of reverted austenite Fe-31.7 wt.% Ni-0.06 wt.% C alloy are presented. The effect of multiple direct γ-α and reverse α-γ martensitic transformations on fragmentation of austenitic grains has been investigated by electron microscopy and X-ray diffraction methods. An ultrafine structure has been formed by nano...

A two-dimensional diffusion based model is developed to describe transformation of austenite into ferrite and pearlite under continuous cooling conditions. The nucleation of ferrite is assumed to occur over grain boundaries and the nucleation of pearlite is assumed to be taking place all over the grain and at growing ferrite–austenite interfaces, when the composition and temperature conditions ...

Calculations verify that carbon diffusion may occur during the lath martensite fomtion. Accordingly,the diffusion of int2rstitial ator ions must be taka into account nhfn martmitic transformtion is defined as a diffusionless transformation. In derivation of the kinetics equation of the ath& martensitic transfomtion,rzgardng the c a r h diffusion, i .e.the enrichment of the austenite during the ...

this study was conducted in order to investigate the influence of plastic deformation on the transformation of retained austenite in a trip steel with a high content of al and a low content of si. to the aim, appropriate treatments were used to produce the starting material (trip steel). the microstructure of the obtained steel was composed of bainite and phases including ferrite and retained a...

The objective of this work was to study materials subjected to external loading where alternative deformation mechanisms are available to generate strains. In the case of shapememory and superelastic NiTi, these mechanisms are twinning and stress-induced phase transformation, respectively. Superelastic NiTi (51.0 at.% Ni) reinforced with 0, 10 and 20 vol.% TiC particles was fabricated by Hot Is...

There are precise observations which indicate the reluctance of excess carbon within bainite or martensite to partition into adjacent austenite in spite of prolonged heat treatment at temperatures where carbon is mobile. To explain this, we report the first calculations of the solubility of carbon in tetragonal ferrite that is in equilibrium with austenite. It is found that the solubility is dr...

A theory is developed for the evolution of bainite as a function of time, temperature, chemical composition and austenite grain size. The model takes into account the details of the mechanism of transformation, including the fact that nucleation begins at the austenite grain surfaces, and that the growth of a sheaf occurs by the repeated nucleation of small platelets. Predictions made using the...

Different techniques have been investigated to seek the best procedure to reveal the prior-austenite grain boundaries in three medium-carbon microalloyed steels. This study has been carried out over a wide range of temperatures (950–1250 C) and it has been found that thermal etching (TE) is the best technique to reveal the prior-austenite grain boundaries in these steels. D 2001 Elsevier Scienc...