Modification of the microstructure of hypoeutectic Al-Si alloys

该项目的目的是澄清锶对亚共晶（xSi<12%）Al-Si合金共晶显微组织形成的影响。尽管至少自1922年以来就知道高达200 ppm的锶的有益作用，但其作用机制仍然未知。因此，目前工作的重点是确定在凝固过程中，锶是偏析，它如何影响共晶硅的结构和机制是负责的效果。此外，重要的合金元素和杂质如Fe、Mn和P的影响以及它们与锶的相互作用必须进行研究。特别是金属间相的形成及其对Sr的存在的依赖性具有实用性（机械性能）和根本性。

The aim of the project was and is to clarify the effect of strontium on the formation of the eutectic microstructure of hypoeutectic (xSi<12%) Al-Si alloys. Although the beneficial action of up to 200 ppm strontium has been known at least since 1922 the mechanism of its action is still unknown. Therefore the emphasis of the current work is to identify where strontium is segregated during solidification, how it influences the structure of the eutectic silicon and which mechanism is responsible for the effect. Moreover the influence of important alloying elements and impurities such as Fe, Mn and P and their interaction with strontium has to be studied. Especially the formation of intermetallic phases and its dependence on the presence of Sr is of practical (mechanical properties) and fundamental interest.