TY - JOUR

T1 - Modelling the role of compositional fluctuations in nucleation kinetics

AU - Ženíšek, J.

AU - Kozeschnik, E.

AU - Svoboda, J.

AU - Fischer, F. D.

PY - 2014/7/31

Y1 - 2014/7/31

N2 - The classical nucleation theory of precipitate nucleation in interstitial/substitutional alloys is applied to account for the influence of spatial A-B composition fluctuations in an A-B-C matrix on the kinetics of nucleation of (A,B)3C precipitates. A and B are substitutional elements in the matrix and C is an interstitial component, assumed to preferentially bind to B atoms. All lattice sites are considered as potential nucleation sites. The fluctuations of chemical composition result in a local variation of the nucleation probability. The nucleation sites are eliminated from the system if they are located in a C-depleted diffusion zone belonging to an already nucleated and growing precipitate. The chemistry is that of an Fe-Cr-C system, and the specific interface energy is treated as a free parameter. Random, regular and homogeneous A-B distributions in the matrix are simulated and compared for various values of the interface energy. An increasing enhancement of the role of compositional fluctuations on nucleation kinetics with increasing interface energy and decreasing chemical driving force is observed.

AB - The classical nucleation theory of precipitate nucleation in interstitial/substitutional alloys is applied to account for the influence of spatial A-B composition fluctuations in an A-B-C matrix on the kinetics of nucleation of (A,B)3C precipitates. A and B are substitutional elements in the matrix and C is an interstitial component, assumed to preferentially bind to B atoms. All lattice sites are considered as potential nucleation sites. The fluctuations of chemical composition result in a local variation of the nucleation probability. The nucleation sites are eliminated from the system if they are located in a C-depleted diffusion zone belonging to an already nucleated and growing precipitate. The chemistry is that of an Fe-Cr-C system, and the specific interface energy is treated as a free parameter. Random, regular and homogeneous A-B distributions in the matrix are simulated and compared for various values of the interface energy. An increasing enhancement of the role of compositional fluctuations on nucleation kinetics with increasing interface energy and decreasing chemical driving force is observed.

KW - Fluctuations of chemical composition

KW - Interface energy

KW - Kinetics

KW - Nucleation and growth

KW - Precipitates

UR - http://www.scopus.com/inward/record.url?scp=84925355492&partnerID=8YFLogxK

U2 - 10.1016/j.actamat.2014.12.031

DO - 10.1016/j.actamat.2014.12.031

M3 - Article

VL - 91

SP - 355

EP - 376

JO - Acta materialia

JF - Acta materialia

SN - 1359-6454

ER -