The present proposal leans on the study of the elastoviscoplastic behavior of a polycrystalline Co by neutron diffraction (ENGIN-X) in line with theoretical investigations : 4 dogbone-shaped samples will be charged in situ under incremental tensile strain at 4 different temperatures (ambient, 400, 450 and 500°C). To obtain a consequent data set for strain analyses, {hk.l} diffraction peaks will be followed along 2 principal directions. Collected patterns will provide the necessary data to establish a reliable model to understand and predict the thermomechanical behavior of Cobalt. It will especially enable the improvement of polycrystalline plasticity models through the integration of additional phenomena such as the contribution of the different deformation mechanisms to the macroscopic behavior with temperature and allotropic transformation induced by temperature and/or plasticity.