This project aims at characterizing the nucleation of pores during heat treatment of 2050 and clarify the origin of this nucleation. We pla to combine in situ nanotomography at 100nm pixel size associated with high resolution holotomography at 35 nm pixel and We FIB/SEM 3D slicing to enhance data obtained during In situ nanotomography. This will help to clarify the site of nucleation of pores inside the grains in correlation with the small intermetallics and precipitates and also at the grain boundary.