UMET - Physical Metallurgy and Materials Engineering

Solute binding energy with a <111> loop containing 37 self-interstitials in α Fe: DFT (density functional theory) calculations. C. Domain, C. Becquart, Journal of Nuclear Materials 499, 582-594 (2018), [doi: 10.1016/j.jnucmat.2017.10.070]

 

Fracture observed after Small Punch Test in presence of liquid metal.

 

Fatigue damage

 

The scientific objectives are to understand the mechanisms of damage of metallic materials. Fatigue damage and cyclic plasticity of metallic alloys are one of the topics initiated at the creation of the laboratory and which contributed to its development and recognition.

An important activity is conducted within the framework of nuclear structural materials. The origin of the damage being radiative, mechanical and corrosive, it is necessary to develop original experimental devices and develop simulation tools. This activity is conducted through two main research areas: liquid metal embrittlement and simulations of microstructures under irradiation.

Galvanization, also a historical topic of the laboratory, is studied through the degradation of metallic materials during their immersion in liquid alloys such as liquid zinc and liquid aluminum.

The scientific objectives targeted in this theme are to design, develop, characterize and test materials or coatings with high performance in terms of their mechanical behavior, heat transfer or resistance to aggressive environments.

This theme is divided into 3 topics:

1. Metal matrix composites
2. Assemblies and surface treatments
3. Advanced metallurgy of alloys out of or at equilibrium

Location of deformation at the grain boundary and intergranular failure studied by TEM, SEM-EBSD and SEM-ECCI

 

Modeling of the Al-C-Fe-Mn diagram using ab initio calculations and cluster models: isothermal and isopleth with constant C content

 

An important part of the activities of the MPGM team consists in developing new experimental and numerical methods to study phase transformations and microstructure evolutions in the context of topics “Understanding damage mechanisms” and “Design of high performance metallic materials”.

On the one hand, we develop numerical methods at the atomic scale to evaluate the energy contributions accompanying the appearance of a new phase or a microstructural defect in a metal matrix. These different quantities can be used as input data for mesoscopic models such as kinetic Monte Carlo object or phase field. Methodological developments are regularly made to improve these approaches and to incorporate new phenomena.

On the other hand we use and improve, within the Chevreul federation, electron diffraction-based techniques at various scales, going from the micro-level to the meso-level (microscopic: TEM (ASTAR) & MEB (TKD), mesoscopic: SEM-EBSD and SEM-ECCI). We also develop methods based on the post-processing of EBSD data (and more commonly Orientation Imaging Microscopy data) to identify and quantify deformation fields (elastic and plastic) via a precise measurement of local disorientation.