Ni-based alloy, ni-based alloy for gas turbine combustor, member for gas turbine combustor, liner member, transition piece member, liner, and transition piece

A Ni-based alloy having a composition comprising, by mass, 20.0% to 26.0% Cr, 4.7% to 9.4% Co, 5.0% to 16.0% Mo, 0.5% to 4.0% W, 0.3% to 1.5% Al, 0.1% to 1.0% Ti, 0.001% to 0.15% C, and at most 5% Fe and the balance of Ni with inevitable impurities,

• wherein the Ni-based alloy comprises titanium nitrides, of which an estimated largest size is an area-equivalent diameter of 12 μm to 25 μm, the estimated largest size of the titanium nitrides being determined by calculating an area-equivalent diameter D which is defined as D=A1/2 in relation to an area A of a titanium nitride with a largest size among titanium nitrides present in a measurement field of view area S0 of an observation of the Ni-based alloy, repeatedly performing this operation for n times corresponding to a measurement field of view number n to acquire n pieces of data of the area-equivalent diameter D, arranging the pieces of data of area-equivalent diameter D in ascending order into D1, D2, . . . Dn to calculate a standardized variable yj which is defined by the following expression:
• yj=−ln [−ln {j/(n+1)}] [Expression 1]
• wherein j denotes the number of the arranged ascending order of the data of the area-equivalent diameter D,
• plotting the area-equivalent diameter D and the standardized variable yj on X and Y axes of an X-Y coordinate system, respectively, to obtain a regression line yj=a×D+b (wherein a and b are constants), calculating yj from the following expression:
• y
• j
• =
• -
• ln
• ⁡
• (
• -
• ln
• ⁢
• S
• S
• 0
• +
• S
• )
• [
• Expression
• ⁢
• ⁢
• 2
• ]
• where a cross-sectional area to be predicted S is 100 mm2, and substituting the obtained value of yj into the regression line to obtain the estimated largest size of the titanium nitrides wherein S0 equals 0.306 mm2, n is greater than or equal to 30, and the observation of the Ni-based alloy is at an observation magnification of 400 to 1000 times or 1000 to 3000 times.