Contamination tolerant hypo- and hypereutectic Al-Si-alloys for additive manufacturing

铝作为一种轻质金属，在航空航天和汽车工业中有着广泛的应用。然而，原铝的生产是非常耗能的。铝的回收利用引入了不同的污染物，例如铁。众所周知，在铝合金中，铁会形成金属间相，如果它们的尺寸太大，就会导致大块材料的脆化。高冷却速率的合成，如增材制造，可能提供一个有趣的回收途径。这可能使增材制造成为可持续封闭材料链的核心过程。热物理性质，如表面张力和粘度，对该工艺非常重要。然而，即使是少量的污染也会对这些特性产生很大的影响。在我们的项目中，将研究铁污染对硅浓度为10 wt.%（亚共晶）和20 wt.%（过共晶）的两种Al-Si合金的影响。虽然AlSi10是LPBF的常用合金，但随着硅含量的增加，加工的工艺窗口变小。铁污染的系统变化可以理解其对制造零件的热物理性质、熔池条件、相形成和缺陷结构的影响。如果污染、热物理性质、相形成和工艺窗口之间的关系是已知的，污染可以通过调整工艺条件来补偿。

Aluminum, as a lightweight metal, is being used in a wide range of applications in the aerospace and automotive industries. However, the production of primary aluminum is very energy intensive. The recycling of aluminum introduces different contaminations such as for example iron. In aluminum alloys, iron is known to form intermetallic phases, which can lead to embrittlement of the bulk material if their size becomes too large. Synthesis with high cooling rates, like additive manufacturing, may offer an interesting recycling route. This may allow additive manufacturing to be a central process in sustainable closed material chains.Thermophysical properties, such as surface tension and viscosity, are of great importance for the process. However, even small amounts of contamination can have a large effect on these properties. In our project, the effect of Fe contamination on two Al-Si alloys with silicon concentrations of 10 wt.% (hypoeutectic) and 20 wt.% (hypereutectic) will be investigated. While AlSi10 is a common alloy for LPBF, the process window for processing becomes smaller with increasing silicon content. A systematic variation of Fe contamination allows to understand its effect on the base of thermophysical properties, meltpool conditions, phase formation and defect structures of manufactured parts.If the relationships between contamination, thermophysical properties, phase formation and process windows are known, contamination can be compensated by adjusted process conditions.