Compositions and single-crystal articles of hafnium-modified and/or zirconium-modified nickel-base superalloys

A composition of matter consisting essentially of, in weight percent:

• a modifying element selected from the group consisting of
• from about 0.25 to about 0.5 percent by weight zirconium,
• combinations of from about 0.2 to about 2.0 percent by weight hafnium and from about 0.25 to about 0.5 percent by weight zirconium, and
• combinations of from about 1.0 to about 2.0 percent by weight hafnium and from about 0.1 to about 0.5 percent by weight zirconium;
• and
• a base alloy composition of from about 0.4 to about 6.5 percent ruthenium, from about 4.5 to about 5.75 percent rhenium, from about 5.8 to about 10.7 percent tantalum, from about 4.25 to about 17.0 percent cobalt, from 0 to about 0.06 percent carbon, from 0 to about 0.01 percent boron, from 0 to about 0.02 percent yttrium, from about 0.9 to about 2.0 percent molybdenum, from about 1.25 to about 6.0 percent chromium, from 0 to about 1.0 percent niobium, from about 5.0 to about 6.6 percent aluminum, from 0 to about 1.0 percent titanium, from about 3.0 to about 7.5 percent tungsten, and wherein the sum of molybdenum plus chromium plus niobium is from about 2.15 to about 9.0 percent, and wherein the sum of aluminum plus titanium plus tungsten is from about 8.0 to about 15.1 percent, balance nickel and incidental impurities.

An article comprising substantially a single crystal, and not a random polycrystal or an oriented polycrystal produced by directional solidification, and having a composition, in weight percent, consisting essentially of

• a modifying element selected from the group consisting of
• from about 0.25 to about 0.5 percent by weight zirconium,
• combinations of from about 0.2 to about 2.0 percent by weight hafnium and from about 0.25 to about 0.5 percent by weight zirconium, and
• combinations of from about 1.0 to about 2.0 percent by weight hafnium and from about 0.1 to about 0.5 percent by weight zirconium;
• and
• a base alloy composition of from about 4 to about 20 percent cobalt, from about 1 to about 10 percent chromium, from about 5 to about 7 percent aluminum, from 0 to about 2 percent molybdenum, from about 3 to about 8 percent tungsten, from about 4 to about 12 percent tantalum, from 0 to about 2 percent titanium, from 0 to about 8 percent rhenium, from 0 to about 6 percent ruthenium, from 0 to about 1 percent niobium, from 0 to about 0.1 percent carbon, from 0 to about 0.01 percent boron, from 0 to about 0.1 percent yttrium, balance nickel and incidental impurities.