Research activities

Research activities at PX-Group Chair – LMTM (Laboratory of Thermomechanical Metallurgy) relate to processing and manufacturing of metals and alloys in the solid state, focusing on the ability to tailor microstructures, and the associated material properties. Topics of interest include recrystallization, precipitation, grain growth, textures and grain boundary engineering, phase transformations, internal stresses and cracking phenomena, with applications to bulk metal forming and laser based additive manufacturing.
An in-house Laser Powder Bed Fusion (LPBF) platform promotes further development of the process, and the enhanced control of microstructures. A new hybrid process called 3D LSP was invented in the lab, and consists in combining LPBF with Laser Shock Peening (LSP) treatments.

The experimental SLM machine developed at EPFL

EPFL-built system used for improving our understanding of the metallurgical and physical aspects of the selective laser melting process.

Laser shock peening can be used alongside selective laser melting in order to increase the strength of 3D printed metal parts.

CAD model and actual part

Taking advantage of the rapid cooling rates of laser processing for building parts made of bulk metallic glasses.

Thermal FEM simulations specifically developed to model the LPBF process.

Using the acoustic emission during the LPBF process to detect defects.

Studying the use of lunar materials in additive manufacturing.

We have rehabilitated the hard-sphere hypothesis and composed it with linear algebra in order to calculate the continuous atomic paths and lattice distortion for the main displacive phase transformations: fcc→bcc, bcc→hcp, fcc→hcp.

Parent grains reconstruction from EBSD map

Structural phase transformations imply a parent phase and a daughter phase, generally linked by a specific orientation relationship. The information on the prior parent grains can be retrieved from the orientations of the daughter grains measured by Electron Back Scatter Diffraction (EBSD) or equivalent techniques.

Investigation both by experiments and numerical modelling of most of the basic concepts of recrystallization and its related phenomena: work hardening, recovery, precipitation, grain growth, etc.