Aluminium powder and its future potential in Additive Manufacturing
by Manja Franke, Head of Research at AMEXCI
AlSi10Mg is one of the most common used alloys in the Additive Manufacturing (AM) market. Thanks to its high corrosion resistance and light weight, it is often chosen for several applications. Our customers are looking more and more into replacing Magnesium with so called “High Strength Aluminium”. Magnesium provides excellent properties but is still challenging the AM world in regards to printability. Although Aluminium cannot compete with an in average 40 % weight reduction like Magnesium, it still offers a lot of advantages. Therefore, it is attractive, leading to more suppliers and higher investigation in general. It can be seen as an alternative for lightweight applications, especially in the aerospace industry using AM.
We see Aluminium in general as one of the highest demanded materials, hence, we also decided to dedicate our new SLM 500 system to only this alloy. With increasing demands on becoming a more sustainable industry, lower energy consumption, and decreased material waste, the usage and further development of these kind of materials and surrounding processes is key. Within our shareholder group, the need for light-weight materials is critical to stay competitive in their respective industry.
Standard AlSi10Mg is for many applications the material of choice and delivers good results and quality. Still, many end products require higher corrosion resistance and especially higher mechanical properties like ultimate tensile strength (UTS), yield tensile strength (YTS), and elongation at break. This is the time where high strength aluminiums come into the market. We currently see a growing development of several new alloys to match these requirements given from the industry. Big suppliers like EOS are working on a material themselves, but also companies like Fehrmann alloys and Constellium, etc. that so far have not been in touch with the AM industry, already have or are working on releasing materials to the market.
Why do we need high strength Aluminiums if standard AlSi10Mg works for many applications as well?
The usual classification of these materials is a yield strength higher than 300 MPa and an Elongation higher than 10 %. There are some materials that can even achieve a YTS of plus 500 MPa and an Elongation of above 20 %. These properties allow even thinner and lighter designs, which results in lower material usage and lower exposure time while printing. In addition, the corrosion resistance of the materials is remarkable and high and fatigue and creep properties are on a level that can resist high load requirements. Especially, industries like Aerospace can benefit from the increased mechanical properties with decreasing weight and also increasing fuel efficiency.
One of the biggest challenges is to make these Aluminium alloys suitable for Additive Manufacturing. Due to the complex microstructure of the materials, it is necessary to develop a powder that works with the laser technology. That is why the current available materials are comparable to already existing alloys known from e.g. casting but still have a slightly different chemical composition.
Our goal is to provide solutions for our customers that not only fit their needs and requirements, but also trying to support their journey of becoming more sustainable through these applications. According to new EU regulations, the carbon dioxide emissions should be decreased by 15 % by 2025, and 31 % by 2030. In order to reach these goals, it is key to increase the usage of light-weight materials for reducing waste and achieving higher efficiency.
At AMEXCI, we offer our customers the possibility to try out new alloys on our ACONITY MIDI machine. This machine offers a huge flexibility and is made for Research & Development. It allows us to easily create Design of Experiments (DoEs) on relatively small powder amounts through our in-house materials lab, which then analyse the samples microstructure, achieved density, tensile strength or hardness. This allows us to continuously improve the part quality until the set goal of our customers is achieved.
We believe that in the future we will see an even more increasing demand for these kind of niche materials, replacing traditional manufacturing with AM processes, still being able to ensure continuous part quality and long lifetimes, while having the advantages and freedom of using Additive Manufacturing for complex structures and components.