| 摘要 |
The present invention provides a nickel base superalloy having an improved combination of stress rupture life and microstructural stability with respect to the formation of TCP phases. A unique feature is the specific combination of the content of the elements ruthenium (Ru), tantalum (Ta) along with a first group of elements consisting of Mo, Cr and Cb in a first range defined by their sum and a second group of elements consisting of Al, Ti and W in a second range defined by their sum in a nickel base superalloy having high contents of rhenium, in excess of 1.3 atomic percent (about 4.0 weight percent) to lower the propensity for TCP phase formation and thus render the alloy more stable at high temperatures. The interaction of Ru with the remaining elements to modify the refractory element phase partitioning provides unique capabilities, causing elements to partition to the gamma phase or the gamma prime phase in a reverse direction than normally experienced in Ni-base superalloys. These Ni-base superalloys are termed Ru-containing Reverse Partitioning Ni-base Superalloys. The composition of these Reverse Partitioning Ni-base superalloys is in the range, in atomic percent, of 1.3-3% Re, 2.0-3.7% Ta, 4.0-18.0% Co, 0-0.2% Hf, 0-0.3%C, 0-0.05% B, 0-0.03% Y, 0-2.0 % Mo, 1.5-7.2% Cr, 0-0.7% Cb, 12.0-15.0% Al, 0-1.3% Ti, 1.0-2.5% W, in combination with 0.25-4.0 Ru and the balance Ni and incidental impurities. <IMAGE> |
