Conditions de traitement thermique de l'alliage de titane ta6v sous faisceau laser co2 de puissance

Abstract Titanium alloys and particularly TA6V are much used in the domain of the aerospace industry and also of chemical engeneering. The thermal treatment by laser of these alloys helps for the improvement of their physico-chemical properties. The laser energy is transformed on the surface of the metallic specimen to thermal energy or heat; this heat diffuses to the interior of the specimen. The microstructure obtained after the laser treatment are metastable ones obtained by quenching out-of equilibrium microstructures; this is due in the case of the laser treatment to the fact that the heating time is a fraction of a second and the cooling rate is very high, in the order of 10 3 K/s. The microstructures obtained are fine with interesting physico-chemical properties. Considering the strong reaction of titanium with O 2 and N 2 , and in order to avoid modifying the resulting microstructure on the surface, a protection against environment during the thermal treatment by laser is required. Blowing argon on the specimens, during the laser treatment results in contaminated materials. The protection against environment is satisfactory when the specimens are treated in a box of Plexiglas filled with argon.