Strengthening and ductilization potentials of nonmetallic solutes in magnesium: First-principles calculation of generalized stacking fault energies

Abstract The ( 0001 ) 10 1 ¯ 0 > and { 11 2 ¯ 2 } 11 2 ¯ 3 > generalized stacking fault energies (GSFEs) and ( 0001 ) surface energies of magnesium alloyed with nonmetallic elements including H, C, N, O and Si were computed using a first-principles method. The calculation results showed that solutes C and H reduced the basal intrinsic SFEs to negative, which enabled the introduction of a high density of basal stacking faults (SFs), thus impeding dislocation slip and strengthening magnesium. By investigating the competition between pyramidal dislocation emission and ( 0001 ) crack propagation, solutes Si, O and N were predicted exhibiting an excellent ductilization capability.