NUCLEATING MECHANISM OF FIVE PETAL STAR-SHAPED PRIMARY SILICON
GUI Manchang (Beijing Institute of Aeronautical Materials; Beijing 100095); JIA Jun; LI Qingchun (Harbin Institute of Technology; Harbin 150001)
Cite this article:
GUI Manchang (Beijing Institute of Aeronautical Materials; Beijing 100095); JIA Jun; LI Qingchun (Harbin Institute of Technology; Harbin 150001). NUCLEATING MECHANISM OF FIVE PETAL STAR-SHAPED PRIMARY SILICON. Acta Metall Sin, 1996, 32(11): 1177-1183.
Abstract Five petal star-shaped primary silicon in hypereutectic Al-Si alloy possesses a nucleating characteristic by agglomerating from tiny polyhedron clasters with simple shape.From the veiwpoint of thermodynamics, it is a spontaneous process that the five fine tetrahedron or octahedron clasters agglomerate in a way of fivefold twinning. The agglomerated polyhedron may grow into a five petal star-shaped primary silicon. By combining clasters with smaller size than that of critical nucleation, the polyhedron can acts as a stable nucleus of primary silicon. Correspondent: GUI Manchang, senior engineer, Post Box 81-3, Beijing Institute of Aeronautical Materials,Beijing 100095