Heterogeneous Nucleation and Grain Formation on Spherical and Flat Substrates

Ma Qian

doi:10.4028/www.scientific.net/MSF.654-656.1339

Paper Titles

Development of High Strength and High Conductivity Cu-Ag-Zr Alloy
p.1323

Cold Joining of Dissimilar Metal Sheets by Shot Peening
p.1327

Study on Powder Metallurgical Preparation of NiCoMnIn Alloy Foam
p.1331

Optimization of the Cooling Process of a Heavy Hydraulic Turbine Runner Band Casting in Heat Treatment
p.1335

Heterogeneous Nucleation and Grain Formation on Spherical and Flat Substrates
p.1339

Researches on the Nucleation Behaviors of NH4Cl Crystal on Coarse Aluminum Surfaces
p.1343

Directional Solidification and Characterization of Al₂O₃/Er₃Al₅O₁₂ Eutectic In Situ Composite by Laser Zone Remelting
p.1347

Microstructure Evolution and Compression Properties of a Directionally Solidified Ni-24.8%Nb Hypereutectic Alloy
p.1351

The Contribution of Diffusion Coefficient to the Eutectic Instability and Amorphous Phase Formation
p.1355

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Heterogeneous Nucleation and Grain Formation on Spherical and Flat Substrates

Abstract:

Turnbull’s transformation nucleus model initiated the concept of a growth barrier for a spherical-cap crystal nucleus growing on a small flat substrate. The recently developed free growth model provided a clear physical picture of the growth barrier concept with experimental and modelling support. Fletcher’s spherical substrate model enhanced the understanding of the geometrical effect of a substrate on nucleation. A recent novel analysis of Fletcher’s model furnished new insights into the similarities and differences between nucleation on spherical and flat substrates. It is necessary to distinguish between the undercooling required for nucleation and that for overcoming the growth barrier; the greater one determines the early stages of grain formation.