The Effect of Carbon and Nickel upon the Stacking-Fault Energy of Iron

A previously established relationship between annealing-twin frequency and twin-boundary energy has been employed in estimating the stacking-fault energies of γ-iron, iron-carbon, and iron-nickel alloys. Measurements were made using electron emission microscopy. The stacking-fault energy of γ-iron was found to be ∼ 75 ergs/cm2; 0.8% carbon raised the value to ∼ 120 ergs/cm2, while 36% nickel reduced it to ∼ 35 ergs/cm2.