André Zaoui  André Zaoui is a French physicist in material mechanics, born on June 8, 1941. He is a corresponding member of the French Academy of sciences and a member of the French Academy of Technologies. Civil Engineer at the École des Mines de Paris (1963), Master of Science in Physics and Mathematics at the Faculty of Sciences in Paris (1965), Doctor of State in Physics at the Faculty of Sciences in Paris (1970), he was a CNRS researcher at the École Polytechnique (1964-1972), Professor of Mechanics at the (1972-89), Research Director at the CNRS at the École Polytechnique (1990-2006) then at ENSAM Paris (2007-2009) and Professor of Mechanics at the École Polytechnique (1990-2004). He has also taught in other higher education establishments (Pierre-et-Marie-Curie University, École des mines de Paris, École nationale des ponts et chaussées, École nationale supérieure de techniques avancées, École centrale Paris). André Zaoui's scientific work covers the fields of research, training and collective research animation. They are focused on the transition from microscopic to macroscopic material mechanics, at the crossroads between the mechanics of continuous media and materials science. His research work has been devoted to investigating the relationships between the microstructure of mesoscale materials (scale of polycrystal grains, inclusions or fibres in composites, phase domains in multiphase materials...) and their macroscopic mechanical behaviour, both in deformation and damage. In this framework, his contributions focus on the design, development and use of theoretical, methodological and experimental tools to link the microscopic and macroscopic scales in materials mechanics. He first (1964-72) studied the viscoplasticity of metals, in particular updating and interpreting the phenomenon of "creep hesitation " : to this end, he contributed to the development of models of the transition from single to polycrystal in elasto(visco)plasticity by proposing a critique of previous models and a secant formulation of the self-coherent model for non-linear behaviours . He then (1972-90) developed a mechanistic approach to crystal plasticity: characterization and representation of latent strain-hardening  for different classes of single crystals, prediction of its role in the strain-hardening of polycrystals, the formation of crystallographic textures and the initiation of plastic instabilities in large deformations (shear bands...); analysis of the mechanical influence of grain boundaries , triple junctions and intergranular sliding on the plasticity of multicrystals and polycrystals.