Uncoupling Growth Mechanisms of Binary Eutectics during Rapid Solidification

Abstract

Eutectic solidification under rapid solidification conditions has enormous applications, as it can produce microstructure-refined and interface-stable combined composite structures with low cost. However, investigations reported that the coupled interfaces will be destroyed under the condition of large undercoolings. For further understanding of the mechanisms of uncoupling growth, we investigated the uncoupling growth process of binary eutectics during rapid solidification using atomistic simulations. We find that both the nucleation rate and the crystallization velocity for the first phase of eutectics are very high; however, nucleation of the second phase is very inactive: its nucleation rate is low and nucleation incubation time is very long. As the nucleation of the eutectic second phase is severely suppressed during rapid solidifications, the crystallization of the second phase lags far behind, therefore we speculate that the uncoupling growth of eutectics during rapid solidification is nucleation-induced.

Atomic-scale investigation of coarsening kinetics by the phase-field crystal model

“…In this work, an atomic-scale numerical method called phase-field crystal (PFC) model [13] was used to study the coarsening process of nanoparticles in semi-solid regions. As a simplified classical density functional theory [14,15], PFC can describe the physical process that happened on atomic length scales and diffusional time scales [16][17][18], which has been successfully used in the study of grain growth, nucleation [19][20][21], and Ostwald ripening with low solid volume fractions [22]. Herein, the kinetics of coarsening with different solid volume fractions and initial size distributions were further studied by the PFC model.…”