PROCESS FOR PREPARING A NICKEL-BASED SUPERALLOY PART AND PART THUS PREPARED

摘要

Process for preparing a nickel-based superalloy part by powder metallurgy: - manufacture of a superalloy with the composition 18 % = Cr = 24 %; 6 % = Mo = 10 %; 2.5 % = Nb = 5 %; traces = Fe = 10 %; traces = Al = 1 %; 0.5 % = Ti = 2.5 %; traces = B = 0,01 %; traces = Mn = 0.35 %; traces = Si = 0.2 %; traces = C = 0.05 %; traces = Co = 2 %; traces = Ta = 0.5 %; traces = Mg = 0.05 %; traces = P = 0.015 %; traces = S = 0.01 %; the rest being nickel and impurities; - atomisation of a molten mass of said superalloy in order to obtain a powder; - screening of said powder; - introduction of the powder into a container; - closure of and application of a vacuum to the container; - densification of the powder and the container by pressurizing them both in order to obtain an ingot or a billet; - hot forming of said ingot or said billet; The densification process is carried out at 500 to 1500 bar, at a temperature at which the fraction by volume of liquid phase in the superalloy is between 0.5 and 10 %, the temperature and the pressure being maintained for 3 to 16 h, and the forging being carried out without intermediate heat treatment after the densification of the powder. A hot formed part thus produced.