The knowledge of some mechanical properties of materials and their changes with thermal treatments and/or mechanical treatments are essential to obtain the best results during simulation of processes. In this paper, changes of Young's modulus at room temperature of colddeformed aluminum AA1050 carried out in a tension machine and changes of Young’s modulus and Poisson’s ratio of AA2024 (T6 and T65) have been determined. The elastics constants have been measured by the ultrasound technique in AA2024 alloy and by tensile test in AA1050. In this alloy, the Young's modulus (E) diminishes during the first step of deformation and then increases with the successive cold working. Changes in Young's modulus measured are around 6-8%. In AA2024, the Young's modulus change is about 3% between the annealed and quenched alloy (minimum value); during aging the E parameter increases with respect to quenching. These changes are correlated with the structural changes during thermal treatments. In AA2024, the E parameter remains almost constant during cold-working after the aging treatment. Poisson’s ratio of this alloy remains almost constant in all the treatments. These results are also correlated with the dislocations arrangement in both materials. This behaviour is also compared with cold-deformed pure iron in a tensile test. These results confirm that aluminum AA1050 present similar behaviour than it was observed for pure iron.