Heat treatments

Since years, the METAL group investigates the role of even more complex heat treatmets on the evolution of metal microstructures. In this field, three topics are of particular interest: the study of phase transformations, welding and diffusion.

PHASE TRANSFORMATION

contact: Pr. Michel Perez, Dr. Véronique Massardier

The improvement of thermomechancal treatments for metal shaping requires the understanding of phase transformations that take part: massive transformations, grain growth, precipitation and recrystallization.

Fig. 1 Nucleation and growth of cementite and ferrite. (a) 3D reconstruction of a Fe-C film (Carbon distribution is in red), (b) XRD spectrum recorded after an isothermal annealing (3600s) for several temperatures, (c) in situ TEM bright field after 3600s at 250°, 350° et 450°C. The TEM images show ferrite and cementite consecutive recristallisations. (Fillon et al. Scripta Materialia 2015)

DIFFUSION

contact: Pr. Patrice Chantrenne

During heat treatments, diffusion in alloys induces phase and microstructures transformations in which electro magnetic fields might play a role. The METAL group develops atomic scale models to better understand the physics at the basis of such microstructure changes. In addition, in order to valid and to improve models and simulations, heat-treatment experiments are carried out in order to observe and measure the microstrure and composition evolution. An original experimental set-up allowing heat treatment under electromagnetic field is under development.

Fig. 2 (a) Scheme of the setup used in the experiment to investigate heat-treatment under electric field (b) Optical image of a steel before/after heat-treatment under electric field (courtesy Pr. P. Chantrenne). 

WELDING

contact: Damien Fabrègue, Sylvain Dancette

Under construction..