Thermodynamic and kinetic properties of carbon (C) atoms in body-centered tetragonal iron (Fe) are investigated by using Monte Carlo (MC) simulations. Pairwise interactions between carbon atoms are obtained by combining the linear elasticity theory and the state-of-the-art results from density functional theory (DFT). This energy database is applie...
The tribological behavior of dual-phase steels was investigated at the effects of different martensite volume fraction (MVF), gaseous environments, and sliding velocities, using a ball-on-disk tribometer, under constant load and dry friction sliding conditions. Furthermore, the tribological behavior of oxide layers formed at different temperatures ...
La présente étude s’intéresse à l’optimisation de la composition chimique, de la microstructure, ainsi qu’au contrôle d’inclusions grossières de type Ti (C,N), sur des aciers martensitiques à haute résistance pour des applications automobiles. Afin de faire varier la résistance mécanique et la propreté inclusionnaire, plusieurs aciers ont été élabo...
Phosphorus intergranular segregation in low alloy steels is known to decrease brittle fracture stress and induce intergranular fracture, which causes reversible temper embrittlement. in the nuclear industry, nominally bainitic steels are subjected to this phenomenon and the question of microstructure susceptibility has been raised as literature sho...
This study deals with Transformation Induced Plasticity (TRIP) observed in martensitic transformation of 36NiCrMo16 steel. In this study, TRIP tests were carried out for two different cases. First, after only free dilatometric (FD) tests, which is used as the reference test for the considered applied stress. Second, with TRIP tests being performed ...
Published in International Journal of Materials Research
The detailed analysis of X-ray diffraction data obtained from intercritically annealed and isothermally transformed low-alloy FeCMnSi TRIP-aided steels reveals that the microstructure contains athermal plate martensite and Fe2C η carbide in addition to ferrite, bainite and residual austenite. Neutron diffraction shows that athermal plate martensite...
Published in International Journal of Materials Research
Es wurden die Härten für die Phasen Ferrit, Martensit und angelassener Martensit an DP-Stählen, sowie für Ferrit und Bainit an TRIP-Stählen ermittelt. Die Ferrithärten von DP- und TRIP-Stählen unterscheiden sich und liegen bei 3,0 bzw. 3,7 GPa. Angelassener Martensit zeigt ca. 6,5 GPa, nichtangelassener Martensit, je nach Kohlenstoffgehalt, ca. 8,5...
Published in International Journal of Materials Research
The mechanical properties of friction-welded pure Cu/CK45 carbon steel joints have been studied. The joint strength increased with increasing upset pressure till it reached a critical value. However, the joint strength was fixed at a low strength with increasing friction time, compared to that of the Cu base metal. The hardness near the interface a...
Using first-principles calculations, we investigated the impact of applied stresses and alloying elements on ferrous martensite nanodomains. In non-alloyed martensite, the procedure revealed that twinned states can be stabilized depending on applied stresses, leading to several possible crystallographic structures: body-centered tetragonal (BCT) ob...
Published in International Journal of Materials Research
A high-carbon metastable austenite phase was quenched in liquid nitrogen to obtain fresh athermal martensite. Different ageing treatments were performed in order to study the transformation of the martensite phase and the formation of carbides. Neutron diffraction experiments give detailed information on the transformations during the annealing tre...
