MIT engineers have broken another record by developing an innovative 3D-printable aluminum alloy boasting outstanding strength and capable of producing lighter, stronger, and more heat-resistant aircraft components. The alloy, made with a combination of machine learning and laser powder bed fusion (LPBF) 3D printing, is five times stronger than conventionally manufactured aluminum, remaining stable at temperatures up to 400 degrees Celsius.
The project began in 2020, as part of a materials design course taught by Professor Greg Olson. Students were challenged to design a stronger printable aluminum alloy, but conventional simulation approaches stalled. “At some point, there are a lot of things that contribute nonlinearly to a material’s properties, and you are lost,” said Mohadeseh Taheri-Mousavi, project lead at MIT. “With machine-learning tools, they can point you to where you need to focus.”
As an alternative to searching through more than a million possible compositions, the machine-learning model enabled the team to narrow the field to just 40 promising mixtures of aluminum and other elements. Once printed, the alloy formed extremely small, densely packed nanoscale structural features called “precipitates” – a process behind the record strength.
To manufacture the alloy, the team used LPBF, a 3D printing process where metal powder is laid down in thin layers and melted with a laser. The rapid heating and cooling help lock in the microstructure. “3D printing opens a new door because of the unique characteristics of the process, particularly, the fast cooling rate,” said John Hart, head of MIT’s Department of Mechanical Engineering.
The scientists say this alloy could replace heavier, costly materials, such as titanium, in jet engine fan blades or similar parts. The innovation will hopefully take flight soon, quite literally. According to the team, their dream is that one day passengers would look out their airplane window and see fan blades made from this aluminum alloy.
