Crystallization in supercooled liquid Cu: Homogeneous nucleation and growth

• Published in: The Journal of chemical physics Vol. 142; no. 6; p. 064704
• Main Authors: E, J. C., Wang, L., Cai, Y., Wu, H. A., Luo, S. N.
• Format: Journal Article
• Language: English
• Published: United States American Institute of Physics 14.02.2015
• Subjects: ATOMS; COMPUTERIZED SIMULATION; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Crystal defects; CRYSTALLIZATION; Crystals; FLUCTUATIONS; GRAIN BOUNDARIES; Ice; INTERFACES; Liquid-solid interfaces; LIQUIDS; Microstructure; Molecular dynamics; MOLECULAR DYNAMICS METHOD; MONOCRYSTALS; NANOSTRUCTURES; NUCLEATION; Probabilistic methods; PROBABILITY; Single crystals; SOLIDS; Stacking faults; Statistical analysis; SUPERCOOLING; TWINNING; Variation; X-RAY DIFFRACTION
• ISSN: 0021-9606; 1089-7690; 1089-7690
• DOI: 10.1063/1.4907627

Homogeneous nucleation and growth during crystallization of supercooled liquid Cu are investigated with molecular dynamics simulations, and the microstructure is characterized with one- and two-dimensional x-ray diffraction. The resulting solids are single-crystal or nanocrystalline, containing various defects such as stacking faults, twins, fivefold twins, and grain boundaries; the microstructure is subject to thermal fluctuations and extent of supercooling. Fivefold twins form via sequential twinning from the solid-liquid interfaces. Critical nucleus size and nucleation rate at 31% supercooling are obtained from statistical runs with the mean first-passage time and survival probability methods, and are about 14 atoms and 1032 m−3s−1, respectively. The bulk growth dynamics are analyzed with the Johnson-Mehl-Avrami law and manifest three stages; the Avrami exponent varies in the range of 1–19, which also depends on thermal fluctuations and supercooling.