Scientists have found a way to improve the performance of 3D-printed aluminum bronze, a metal that could be useful for cooling powerful electronic components in rockets, aircraft and electric vehicles.
Researchers from Skoltech and State Marine Technical University studied how different heat treatments affect aluminum bronze made using 3D printing.
They discovered that heating the printed metal to the right temperature can create a better balance between strength and ductility—the ability of a material to bend or stretch without breaking.
The findings were published in the Journal of Alloys and Compounds.
Modern electronics generate a lot of heat, especially powerful processors and other components used in demanding environments.
Heat exchangers help carry this heat away, preventing sensitive electronics from overheating.
The material used to make these cooling systems needs to conduct heat effectively while also being mechanically strong. This becomes especially important in rockets, aircraft and electric cars, where components may experience vibration, shocks and repeated changes in temperature and mechanical stress.
Copper might seem like an obvious choice because it conducts heat extremely well. However, pure copper can be difficult to 3D-print using conventional infrared lasers. Its high thermal conductivity quickly carries heat away from the printing area, while its highly reflective surface makes it difficult for the laser energy to be absorbed. Copper is also relatively soft, meaning thin structures can deform under mechanical loads.
One possible solution is aluminum bronze, an alloy containing copper mixed with about 10% aluminum and 1% iron. The alloy is easier to print and mechanically stronger than pure copper, although its thermal conductivity is lower.
But 3D printing creates another problem. Metal cools and solidifies extremely quickly during printing, which can produce uneven chemical compositions and unstable microscopic structures. These tiny differences can affect how strong or flexible the finished component is.
After examining 3D-printed aluminum bronze under a scanning electron microscope, the researchers suspected that heat treatment after printing could improve its internal structure.
They placed samples in an electric furnace for three hours at three different temperatures: 300°C, 400°C and 500°C. They then tested the samples and compared them with aluminum bronze that had received no heat treatment.
The temperature turned out to be crucial.
Heating the metal at 300°C or 400°C actually made its properties worse. These temperatures encouraged the formation of unstable phases within the material, reducing its ductility and making it more brittle.
The results were very different at 500°C. At this temperature, atoms were able to move and redistribute more effectively within the alloy. This reduced chemical irregularities and created a more stable microscopic structure. The result was a much better balance between strength and ductility.
The researchers say the findings show why heat treatments developed for conventionally manufactured metals cannot simply be applied to 3D-printed materials without careful testing.
The next step is to determine whether heating the aluminum bronze to 500°C affects its ability to conduct heat. If the alloy retains good thermal conductivity, the technique could provide a practical way to manufacture durable, complex cooling components for high-performance electronics used in electric vehicles, aircraft, rockets and other demanding technologies.
