In this work, the internal characteristics of the primary silicon (Si) crystals in strontium (Sr)-modified Zn–Al–Si alloys were investigated in detail. The results showed that Sr has a significant spheroidizing effect on the primary Si and a large number of spheroidal primary Si particles contain a series of parallel hexagonal or approximate hexagonal growth traces, which correspond to an actual three-dimensional tetrakaidecahedron structure. Furthermore, faceted–nonfaceted interface transitions take place during the growth process of the primary silicon. The deeply etched sample reveals the existence of residual tetrakaidecahedron in Sr-modified alloy and proves that tetrakaidecahedron is an important growth stage of the spherical silicon. The variation of supercooling associated with strontium addition probably results in the faceted–nonfaceted interface transitions and the formation of the tetrakaidecahedron, which has a special polycrystalline structure and contains high-density of paralleling and intersecting {111}Si twins.

在这项工作中，详细研究了锶 (Sr) 改性 Zn-Al-Si 合金中初生硅 (Si) 晶体的内部特性。结果表明，Sr对初生Si具有显着的球化作用，大量球状初生Si颗粒含有一系列平行六边形或近似六边形的生长轨迹，对应于实际的三维十四面体结构。此外，在初级硅的生长过程中会发生多面-非多面界面转变。深蚀刻样品揭示了Sr改性合金中残留的十四面体的存在，证明了十四面体是球形硅的重要生长阶段。