Direct observations of nucleation in a nondilute multicomponent alloy

Sudbrack, Chantal K.; Noebe, Ronald D.; Seidman, David N.

Direct observations of nucleation in a nondilute multicomponent alloy

Authors

Sudbrack, Chantal K.

Noebe, Ronald D.

Seidman, David N.

Description

The chemical pathways leading to gamma-prime(L1_2)-nucleation from nondilute Ni-5.2 Al-14.2 Cr at.%, gamma(f.c.c.), at 873 K are followed with radial distribution functions and isoconcentration surface analyses of direct-space atom-probe tomographic images. Although Cr atoms initially are randomly distributed, a distribution of congruent Ni3Al short-range order domains (SRO), <R> =0.6 nm, results from Al diffusion during quenching. Domain site occupancy develops as their number density increases leading to Al-rich phase separation by gamma-prime-nucleation, <R>=0.75 nm, after SRO occurs.
5 pages, 4 figures