HIGH-STRENGTH, HEAT-RESISTANT Ni-BASE ALLOY, METHOD FOR PRODUCING SAME, AND GAS TURBINE BLADE

Abstract

Provided is a high-strength, heat-resistant, Ni-base alloy comprising Co: from 5 to 12%, Cr: from 5 to 12%, Mo: from 0.5 to 3.0%, W: from 3.0 to 6.0%, Al: from 5.5 to 7.2%, Ti: from 1.0 to 3.0%, Ta: from 1.5 to 6.0%, Re: from 0 to 2.0%, and C: from 0.01 to 0.20%. The high-strength, heat-resistant, Ni-base alloy is constituted of a Ni-based alloy, the balance of the Ni-based alloy comprising Ni and inevitable impurities. The density of the high-strength, heat-resistant Ni-base alloy is less than 8.5 g/cm 3 .

1 . A high-strength, heat-resistant Ni-base alloy constituted of a Ni-base alloy comprising, by mass %:
 Co: from 5 to 12%,   Cr: from 5 to 12%,   Mo: from 0.5 to 3.0%,   W: from 3.0 to 6.0%,   Al: from 5.5 to 7.2%,   Ti: from 1.0 to 3.0%,   Ta: from 1.5 to 6.0%,   Re: from 0 to 2.0%, and   C: from 0.01 to 0.20%,   the balance of the Ni-base alloy comprising Ni and inevitable impurities, and   a density of the high-strength, heat-resistant Ni-base alloy being less than 8.5 g/cm 3 .   
     
     
         2 . The high-strength, heat-resistant Ni-base alloy according to  claim 1 , wherein
 the Ni-base alloy further comprises one or more among B: from 0.005 to 0.030%, Hf: from 0.01 to 0.15%, and Zr: from 0.001 to 0.02%.   
     
     
         3 . The high-strength, heat-resistant Ni-base alloy according to  claim 1 , wherein
 a Mo content in the Ni-base alloy is in a range of from 1.0 to 2.5%.   
     
     
         4 . The high-strength, heat-resistant Ni-base alloy according to  claim 1 , wherein
 an Al content in the Ni-base alloy is in a range of from 5.8 to 6.4%.   
     
     
         5 . The high-strength, heat-resistant Ni-base alloy according to  claim 1 , wherein
 a Ti content in the Ni-base alloy is in a range of from 1.5 to 3.0%.   
     
     
         6 . The high-strength, heat-resistant Ni-base alloy according to  claim 1 , wherein
 a parameter P1 defined by Equation (1) by the content (mass %) of each component is taken to be a second-phase shape parameter P1, and a content of each component of the Ni-base alloy is set such that the second-phase shape parameter P1 is in a range of from −0.4 to −0.24,
     P 1=1.2−0.0036×[% Co]−0.023×[% Cr]−0.072×[% Mo]−0.029×[% W]−0.12×[% Al]−0.072×[% Ti]−0.014×[% Ta]−0.06×[% Re]−0.13×[% C]  (1).
 
   
     
     
         7 . The high-strength, heat-resistant Ni-base alloy according to  claim 6 , wherein
 the content of each component of the Ni-base alloy is set such that the second-phase shape parameter P1 is in a range of from −0.35 to −0.26.   
     
     
         8 . The high-strength, heat-resistant Ni-base alloy according to  claim 1 , wherein
 a parameter P2 defined by Equation (2) by a content (mass %) of each component is taken to be a phase stability parameter P2, and the content of each component of the Ni-base alloy is set such that the phase stability parameter P2 is in a range of from −1.0 to 0,
     P 2 =0.06×[% Co]+0.44×[% Cr]+0.6×[% Mo]+0.48×[% W]+2.2×[% Al]+1.8×[% Ti]+0.65×[% Ta]+0.35×[% Re]−0.46×[% C]−26.4   (2).
 
   
     
     
         9 . The high-strength, heat-resistant Ni-base alloy according to  claim 8 , wherein
 the content of each component of the Ni-base alloy is set such that the phase stability parameter P2 is in a range of from −0.7 to 0.   
     
     
         10 . The high-strength, heat-resistant Ni-base alloy according to  claim 1 ; wherein
 the high-strength, heat-resistant Ni-base alloy is a directionally solidified alloy.   
     
     
         11 . A method for producing a high-strength, heat-resistant Ni-base alloy using the Ni-base alloy according to  claim 1 , the method comprising;
 as solution heat treatment, heating a directionally solidified alloy of the Ni-alloy to a temperature in a range of from 1180 to 1320° C. and cooling, and then;   as stabilization heat treatment, heating the cast material to a temperature in a range of from 1050 to 1150° C. and cooling; and then   as aging heat treatment, heating the cast material to a temperature in a range of from 800 to 900° C. for not less than 4 hours.   
     
     
         12 . The method for producing a high-strength, heat-resistant Ni-base alloy according to  claim 11 , wherein
 the high-strength, heat-resistant Ni-base alloy is a gas turbine blade.   
     
     
         13 . A gas turbine blade made from the high-strength, heat-resistant Ni-base alloy according to  claim 1 .