定向凝固晶粒竞争生长的研究进展

Competitive growth between different structures including phases, dendrites and grains is a common phenomenon existing in various microstructure evolution processes. The overgrowth outcome of competitive growth has a paramount influence on final solidification microstructures and mechanical behaviors of materials. The competitive grain growth during directional solidification is a key factor for microstructures controlling, especially for the preparation of single crystal turbine blades. In recent years, the competitive grain growth during directional solidification becomes a hot spot due to an increasing demand for the single crystal preparation and inconsistent experimental results with the classical Walton-Chalmers model. In this paper, the mechanism of competitive grain growth based on the classical Walton-Chalmers model and its challenges were firstly discussed, and then some recent research progresses in converging growth and diverging growth in two dimensional spaces, and non-uniplanar growth in three dimensional spaces were reviewed. Furthermore, the recent works of our group on competitive grain growth during directional solidification by using the phase field method were introduced. Finally, the outlooks of future studies on competitive grain growth during directional solidification are presented.