Ni-Based Alloy Softened Powder and Method for Manufacturing Same

A method for manufacturing an Ni-based alloy softened powder having a chemical composition allowing γ′ phase precipitated in γ phase as a matrix to have an equilibrium precipitation amount of 30 volume % or more and 80 volume % or less at 700° C., the softened powder having an average particle size of 5 μm or more and 500 μm or less, the softened powder comprising particles comprising a polycrystalline body of fine crystals of the γ phase, the particles having a Vickers hardness of 370 Hv or less at room temperature, the method comprising:

• a precursor powder preparation step of preparing a precursor powder that has the chemical composition and comprises particles comprising a polycrystalline body of fine crystals of the γ phase;
• and
• a powder softening high temperature and slow cooling heat treatment step of subjecting the precursor powder to a high temperature and slow cooling heat treatment in which the precursor powder is heated to a temperature that is equal to or higher than the solvus temperature of the γ′ phase and lower than the melting point of the γ phase to cause the γ′ phase to enter into solid solution in the γ phase and subsequently cooled slowly from this temperature to a temperature lower than the solvus temperature of the γ′ phase at a cooling rate of 100° C./h or less to produce the Ni-based softened powder in which the γ′ phase is precipitated on grain boundaries of the fine crystals of the γ phase in an amount of 20 volume % or more.

A method for manufacturing an Ni-based alloy softened powder having a chemical composition allowing γ′ phase precipitated in γ phase as a matrix to have an equilibrium precipitation amount of 30 volume % or more and 80 volume % or less at 700° C., the softened powder having an average particle size of 5 μm or more and 500 μm or less, the softened powder comprising particles comprising a polycrystalline body of fine crystals of the γ phase, the particles having a Vickers hardness of 370 Hv or less at room temperature, the method comprising:

• a single-phase precursor powder preparation step of preparing a single-phase precursor powder that has the chemical composition and comprises particles comprising a polycrystalline body of single-phase fine crystals of the γ phase;
• and
• a powder softening sub-high temperature and slow cooling heat treatment step of subjecting the single-phase precursor powder to a sub-high temperature and slow cooling heat treatment in which the single-phase precursor powder is heated to a temperature that is equal to or higher than a temperature 80° C. lower than the solvus temperature of the γ′ phase and lower than the solvus temperature and cooled slowly from this temperature at a cooling rate of 100° C./h or less to produce the Ni-based softened powder in which the γ′ phase is precipitated on grain boundaries of the single-phase fine crystals of the γ phase in an amount of 20 volume % or more.

A method for manufacturing an Ni-based alloy softened powder having a chemical composition allowing γ′ phase precipitated in γ phase as a matrix to have an equilibrium precipitation amount of 30 volume % or more and 80 volume % or less at 700° C., the softened powder having an average particle size of 5 μm or more and 500 μm or less, the softened powder comprising particles comprising a polycrystalline body of fine crystals of the γ phase, the particles having a Vickers hardness of 370 Hv or less at room temperature, the method comprising:

• a single-phase precursor powder preparation step of preparing a single-phase precursor powder that has the chemical composition and comprises particles comprising a polycrystalline body of single-phase fine crystals of the γ phase;
• and
• a powder softening high temperature and slow cooling heat treatment step of subjecting the precursor powder to a high temperature and slow cooling heat treatment in which the single-phase precursor powder is heated to a temperature that is equal to or higher than the solvus temperature of the γ′ phase and lower than the melting point of the γ phase and subsequently cooled slowly from this temperature to a temperature lower than the solvus temperature of the γ′ phase at a cooling rate of 100° C./h or less to produce the Ni-based softened powder in which the γ′ phase is precipitated on grain boundaries of the single-phase fine crystals of the γ phase in an amount of 20 volume % or more.