MIT researchers developed what might be a revolutionary 3D printable aluminum alloy, and they did so with a very interesting approach.
Aluminum is a popular material because it is a relatively strong metal that is very lightweight. It’s ideal for aerospace applications, where weight counts.
However, there’s a problem with aluminum: it has a very low softening temperature. Typically it should be used in applications where temperatures don’t go much higher than 200C, otherwise you risk softening the metal.
That constraint takes out quite a few potential applications. Pretty much anything that involves notable heat cannot use aluminum.
The MIT researchers were challenged to develop a new aluminum alloy that had a higher softening temperature. This is usually done by mixing in other elements that end up as precipitates within the alloy as it cools. The researchers attempted a number of different combinations, but none seemed to do the trick.
Then they came upon a new approach: machine learning. They collected the relevant information and set up a machine learning system that could process over a million possible combinations using simulation. They ended up with 40 different options that showed promise.
These were then physically tested, and they ended up with a single alloy formulation that actually worked.
Here’s the interesting part: for the alloy to be most effective, the precipitates should be as small as possible. However, this doesn’t tend to happen with traditional casting, where cooling is quite slow. That extra time allows the precipitates to collect and form larger particles.
Instead they turned to LPBF 3D printing, where small amounts of powder material are fused instantly. The cooling takes place rapidly, keeping the size of the precipitates small, and optimizing the properties of the metal alloy.
In other words, this new aluminum alloy works best when 3D printed, and does not work very well when cast.
How well does it work? The researchers found that metal samples were stable at extremely high temperatures, up to an incredible 400C. That would put it somewhere between copper and steel as far as thermal properties go.
This could unlock a huge number of high temperature applications, particularly in the aerospace industry.
Via MIT
