Nickel-base superalloy, unidirectional-solidification process therefor, and castings formed therefrom

摘要

An alloy composition and method by which the incidence of freckling can be reduced in castings (10,32) produced with properties similar to the René N5 nickel-base superalloy. The casting (10,32) has a unidirectional crystal structure and a composition consisting of, by weight, 6% to 8% chromium, 6% to 9% cobalt, 0% to 2% molybdenum, 4% to 6% tungsten, 6.4% to 6.9% tantalum, 0% to 2% titanium, 5% to 7% aluminum, 2.7% to 3.0% rhenium, 0.3% to 0.7% hafnium, 0.04% to 0.08% carbon, 0.002% to 0.006% boron, 0% to 0.075% yttrium, 0.002% to 0.004% zirconium, the balance being nickel and incidental impurities.