Method for Manufacturing Nickel-Based Alloy Repaired Member

1 . A manufacturing method of a Ni-based alloy repaired member in that a repair piece is formed at a damaged portion of a base material, each of the base material and the repair piece being made of a Ni-based alloy having a chemical composition in which the equilibrium amount of precipitation of a ′ phase precipitating in a phase of matrix at 700° C. is 30 volume % or more and 80 volume % or less,

the manufacturing method comprising:

a damaged portion surface preparation step for preprocessing a surface of the damaged portion;

an alloy powder preparation step for preparing a Ni-based alloy powder having the chemical composition;

a sprayed piece deposition step for depositing/forming a sprayed piece on the damaged portion by a high-speed collision spraying process using the Ni-based alloy powder;

a softening heat treatment step for heating the sprayed piece to a temperature equal to or higher than the solvus temperature of the ′ phase but lower than the melting temperature of the phase, and then slow-cooling the heated sprayed piece from the temperature to a temperature at least 50° C. lower than the ′ phase solvus temperature at a cooling rate of 100° C./h or lower, so that the sprayed piece is thermally refined to a softened sprayed piece in that particles of the ′ phase at least 20 volume % precipitate on grain boundaries of the phase grains having an average grain diameter of 50 μm or less;

a shaping step for processing the softened sprayed piece into a shaped sprayed piece with a desired shape by cold plastic working, warm plastic working and/or machining; and

a solution and aging heat treatment step for subjecting whole of the shaped sprayed piece and the base material to a solution heat treatment so as to solid-dissolve the ′ phase into the phase and subsequently subjecting it to an aging heat treatment so as to precipitate particles of the ′ phase of at least 30 volume % within the phase grains, so that the shaped sprayed piece is thermally refined to the repair piece.

2 . The manufacturing method according to claim 1 , wherein

the high-speed collision spraying process is a high velocity oxy-fuel spraying, a high velocity air-fuel spraying or a cold spraying.

3 . The manufacturing method according to claim 1 , wherein

the softened sprayed piece has a Vickers hardness of 390 Hv or less at a room temperature.

4 . The manufacturing method according to claim 1 , wherein

the alloy powder preparation step includes an atomization substep for forming the Ni-based alloy powder.

5 . The manufacturing method according to claim 1 , wherein

the chemical composition of the repair piece is:

5 mass % to 25 mass % of Cr,

more than 0 mass % to 30 mass % of Co,

1 mass % to 8 mass % of Al,

1 mass % to 10 mass % of Ti, Nb and Ta in total,

10 mass % or less of Fe,

10 mass % or less of Mo,

8 mass % or less of W,

0.1 mass % or less of Zr,

0.1 mass % or less of B,

0.2 mass % or less of C,

2 mass % or less of Hf,

5 mass % or less of Re,

0.003 mass % to 0.05 mass % of O, and

residual components of Ni and unavoidable impurities.

6 . The manufacturing method according to claim 1 , wherein

each of the base material and the repair piece has a chemical composition in which the solvus temperature of the ′ phase is 1110° C. or higher.

7 . The manufacturing method according to claim 6 , wherein

each of the base material and the repair piece has a chemical composition in which the equilibrium amount of precipitation of the ′ phase at 700° C. is 45 volume % or more and 80 volume % or less.

8 . The manufacturing method according to claim 1 , wherein

the based material is a unidirectional solidification article or a single crystalline solidification article comprising the phase, and

the solution heat treatment is a solution/non-recrystallization heat treatment in which the whole of the shaped sprayed piece and the base material is held at a temperature at least 10° C. higher than the solvus temperature of the ′ phase but not higher than a temperature that is 10° C. lower than the melting point of the phase, for a holding duration within a time range in which recrystallized grains of the phase do not generate.

9 . The manufacturing method according to claim 8 , wherein

the holding duration in the solution/non-recrystallization heat treatment step is within a range from 15 minutes to 2 hours.