Combining first-principles calculations with recently developed statistical physics tools, we determine carbon diffusion mechanisms and the resulting coefficients in pure-Fe weakly alloyed ${M}_{3}\mathrm{C}$ cementites. The predicted ${\mathrm{Fe}}_{3}\mathrm{C}$ are good agreement experimental measurements of carburization rate ferritic steels. In our proposed mechanisms, C migrates by jumps ...

The precipitation and Ostwald ripening behaviour of needle shaped Mo2C particles during the tempering of a ternary Fe –C –Mo martensitic steel have been characterised and modelled, taking account of local equilibrium, the capillarity effect, and the simultaneous enrichment and dissolution of cementite. Particles of Mo2C are represented as paraboloids of revolution, with the tip radius chosen to...

The effect of an addition of 0.37 Wt % Won the overall transformation rate of the austenitepearlite reaction in a eutectoid steel is examined. Pearlite growth rates and interlamerllar spacing are measured as a function of transformation temperatures. Tungesten raises the Ael temperature, for most transformation temperatures, decreases the overall reaction rate, the growth rate and the interlame...

The manganese-rich ternary cementite phase Mn1.8Fe1.2C has been synthesized by a ceramic route in an almost quantitative yield, and the crystal structure refinement on the basis of high-resolution X-ray powder diffraction data using MoKα1 radiation has been performed. The carbon atom is found in a slightly distorted trigonal prism composed of Mn and Fe atoms, with a rather narrow bond length ra...

Internal crystalline structure of cementite catalyst particles located inside the base of multiwall carbon nanotubes was studied using nanoprobe convergent-beam electron diffraction. The catalyst particles are single crystalline but exhibit combinations of small-angle ( 1 –3 ) rotations, twists, and bends along their axial length between adjacent locations. Distortions are most severe away from...

When using traditional metallographic techniques, materials scientists often make assumptions about the shape, distribution and connectivity of three-dimensional features that lie buried within the material. Recent work has shown that these assumptions can be incorrect. An approach to threedimensional analysis of microstructures is demonstrated here in three different alloy steels. Proeutectoid...

The present article is concerned with a theoretical and experimental study of the growth kinetics of pearlite in a 0.4C-1.6Mn medium carbon steels. Factors controlling the isothermal formation of this microconstituent are explored in this work. In this sense, the transition temperature between local equilibrium (LE) and no partition local equilibrium (NPLE) growth mechanisms is theoretically de...

This work investigates the microstructure and inclusions of a compacted graphite iron (CGI) alloyed by Ce La rare earth (RE) elements. In our study, alloying elemental distribution solute segregation were characterized methods secondary ion mass spectrometry (SIMS) three-dimensional atom probe (3DAP) with high sensitivity spatial resolution. RE sulfide, MgS, carbide, composite formed during sol...

Softening frequently occurs in dual-phase steels under isothermal tempering of martensite. Recently, non-isothermal tempering is implemented to decrease the softening process in dualphase steels. Here, we have discovered using high power electropulsing treatment can significantly enhance the strengthening effects via the formation of ultrafine-grained ferrite with nano-cementite particles in te...

The precipitation and Ostwald ripening behaviour of V4C3 (plate shaped) particles during the tempering of a ternary Fe – C –V martensitic steel have been characterised and modelled, taking account of local equilibrium, the capillarity effect, and simultaneous cementite enrichment and dissolution. Particles of V4C3 are represented as parabolic cylinders of revolution, with the tip radius chosen ...