CAST NICKEL-BASE SUPERALLOY INCLUDING IRON

A cast nickel-base superalloy that includes iron added substitutionally for nickel. The cast nickel-base superalloy comprises, in weight percent about 1-6% iron, about 7.5-19.1% cobalt, about 7-22.5% chromium, about 1.2-6.2% aluminum, optionally up to about 5% titanium, optionally up to about 6.5% tantalum, optionally up to about 1% Nb, about 2-6% W, optionally up to about 3% Re, optionally up to about 4% Mo, about 0.05-0.18% C, optionally up to about 0.15% Hf, about 0.004-0.015 B, optionally up to about 0.1% Zr, and the balance Ni and incidental impurities. The superalloy is characterized by a γ′ solvus temperature that is within 5% of the γ′ solvus temperature of the superalloy that does not include 1-6% Fe and a mole fraction of γ′ that is within 15% of the mole fraction of the superalloy that does not include 1-6% Fe.